A Behavioral Approach to Law and Economics
Christine Jolls,* Cass R. Sunstein,** and Richard Thaler***

* Assistant Professor of Law, Harvard Law School. ** Karl N. Llewellyn Distinguished Service Professor of Jurisprudence, University of Chicago. *** Robert P. Gwinn Professor of Economics and Behavioral Science, Graduate School of Business, University of Chicago. We acknowledge the helpful comments of Ian Ayres, Lucian Bebchuk, Colin Camerer, David Charny, Richard Craswell, Jon Elster, Nuno Garoupa, J.B. Heaton, Samuel Issacharoff, Dan Kahan, Louis Kaplow, Lewis Kornhauser, Lawrence Lessig, Steven Levitt, A. Mitchell Polinsky, Eric Posner, Richard Posner, Richard Revesz, Steven Shavell, Jonathan Zittrain, Ari Zweiman, and participants at the American Law and Economics Association Annual Meeting, the Boston University Law School Faculty Workshop, the Columbia University Law and Economics Workshop, workshops at Harvard Law School on law and economics and on rationality, the NBER Behavioral Law and Economics Conference, the NYU Rational Choice Colloquium, and the University of Chicago Law and Economics Workshop. Todd Murtha and Gil Seinfeld provided outstanding research assistance. Nicole Armenta provided helpful material on criminal abstinence programs. This work was finished while Thaler was a Fellow at the Center for Advanced Study in the Behavioral Sciences; he is grateful for the Center’s support.

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INTRODUCTION .................................................................................... I. FOUNDATIONS: WHAT IS “BEHAVIORAL LAW AND ECONOMICS”? ................................................................................ A. Homo Economicus and Real People ....................................... 1. Bounded rationality .......................................................... 2. Bounded willpower ........................................................... 3. Bounded self-interest ........................................................ 4. Applications ...................................................................... B. Testable Predictions ................................................................ C. Partial and Ambiguous Successes of Conventional Economics ............................................................................... D. Parsimony................................................................................ II. BEHAVIOR OF AGENTS ................................................................... A. The Ultimatum Game .............................................................. 1. The game and its sunk-cost variation ............................... 2. Fairness, acrimony, and scruples ..................................... B. Bargaining Around Court Orders ........................................... 1. Coasian prediction............................................................ 2. Behavioral analysis........................................................... 3. Evidence............................................................................ C. Failed Negotiations ................................................................. 1. Self-serving conceptions of fairness.................................. 2. Evidence............................................................................ 3. The role of lawyers ........................................................... D. Mandatory Contract Terms ..................................................... 1. Wage and price effects...................................................... 2. Behavioral analysis........................................................... III. THE CONTENT OF LAW .................................................................. A. Bans on Market Transactions.................................................. 1. Bans on economic transactions ........................................ 2. Other bans ........................................................................ B. Prior Restraints on Speech...................................................... C. Anecdote-Driven Environmental Legislation (With Particular Reference to Superfund) ........................................ 1. Estimating the likelihood of uncertain events................... 2. Superfund .......................................................................... IV. PRESCRIPTIONS .............................................................................. A. Negligence Determinations and Other Determinations of Fact or Law ............................................................................. 1. Background.......................................................................

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Objections to the rational actor model in law and economics are almost as old as the field itself. Early skeptics about the economic analysis of law were quick to marshal arguments from psychology and other social sciences to undermine its claims.1 But in law, challenges to the rational actor assumption by those who sympathize with the basic objectives of economic analysis have been much less common. The absence of sustained and comprehensive economic analysis of legal rules from a perspective informed by insights about actual human behavior makes for a significant contrast with many other fields of economics, where such “behavioral” analysis has become relatively common.2 This is especially odd since law is a domain where behavioral analysis would appear to be particularly promising in light of the fact that nonmarket behavior is frequently involved. Our goal in this article is to advance an approach to the economic analysis of law that is informed by a more accurate conception of choice, one that reflects a better understanding of human behavior and its wellsprings. We build on and attempt to generalize earlier work in law outlining behavioral findings by taking the two logical next steps: proposing a systematic framework for a behavioral approach to economic analysis of law, and using behavioral insights to develop specific models and approaches addressing top-

1. See, e.g., Mark Kelman, Consumption Theory, Production Theory, and Ideology in the Coase Theorem, 52 S. CAL. L. REV. 669 (1979); Duncan Kennedy, Cost-Benefit Analysis of Entitlement Problems: A Critique, 33 STAN. L. REV. 387 (1981); Arthur Allen Leff, Economic Analysis of Law: Some Realism About Nominalism, 60 VA. L. REV. 451 (1974). 2. See, e.g., volume 112, issue 2 of the Quarterly Journal of Economics, which contains 11 articles related to behavioral economics.

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ics of abiding interest in law and economics.3 The analysis of these specific topics is preliminary and often in the nature of a proposal for a research agenda; we touch on a wide range of issues in an effort to show the potential uses of behavioral insights. The unifying idea in our analysis is that behavioral economics allows us to model and predict behavior relevant to law with the tools of traditional economic analysis, but with more accurate assumptions about human behavior, and more accurate predictions and prescriptions about law. Certainly a great deal of work would be necessary to justify a final evaluation of most of the topics pursued here; there is fertile ground for future research, both theoretical and empirical, and one of our principal goals is to suggest the directions in which that research might go. We suggest that an approach based on behavioral economics will help with the three functions of any proposed approach to law: positive, prescriptive, and normative.4 The positive task, perhaps most central to economic analysis of law and our principal emphasis here, is to explain both the effects and content of law. How will law affect human behavior? What will individuals’ likely response to changes in the rules be? Why does law take the form that it does? A superior understanding of human behavior will improve answers to such questions. The prescriptive task is to see how law might be used to achieve specified ends, such as deterring socially undesirable behavior. Much of conventional economic analysis is concerned with this sort of question. Explicit consideration of behavioral factors can improve the prescriptions offered by the analyst. For instance, instead of focusing only on the actual probability of detecting criminal behavior in considering whether offenders will be deterred, the analyst might also want to consider the perceived probability of detection and how it might differ in systematic and predictable ways from the actual probability. The normative task is to assess more broadly the ends of the legal system. In conventional economic analysis, normative analysis is no different from prescriptive analysis, since the goal of the legal system is to maximize
3. The existing legal literature includes several articles that generally catalogue behavioral findings and suggest legal issues to which these findings might be relevant. See Ward Edwards & Detlof von Winterfeldt, Cognitive Illusions and Their Implications for the Law, 59 S. CAL. L. REV. 225 (1986); Melvin Aron Eisenberg, The Limits of Cognition and the Limits of Contract, 47 STAN. L. REV. 211 (1995); Robert C. Ellickson, Bringing Culture and Human Frailty to Rational Actors: A Critique of Classical Law and Economics, 65 CHI.-KENT L. REV. 23 (1989); Cass R. Sunstein, Behavioral Analysis of Law, 64 U. CHI. L. REV. 1175 (1997). The existing literature also includes a number of articles that use behavioral insights to analyze specific topics in the economic analysis of law—primarily the Coase theorem and behavior during bargaining. These articles are relevant to a few of the issues we discuss below, and we will draw on them in analyzing those issues. 4. For a similar distinction between positive, prescriptive, and normative analysis, see David E. Bell, Howard Raiffa & Amos Tversky, Descriptive, Normative, and Prescriptive Interactions in Decision Making, in DECISION MAKING 9 (David E. Bell, Howard Raiffa & Amos Tversky eds., 1988); Sunstein, supra note 3.

on how to maximize social welfare. We attempt to sketch several such models here. Each of these three strands of our project is deeply constructive. with economics. Because of the complexity of these issues. and the prospect that some methods of correction (such as those that . Our topics here include bargaining behavior and the effects of mandatory contract terms. obviously issues of paternalism become central here. This is so because people’s revealed preferences are a less certain ground on which to build. and our goal is to strengthen the predictive and analytic power of law and economics. Part V is more speculative and normative. and prescriptive (in our sense of the term) analysis also focuses. rather it suggests. We briefly outline the main problems—some familiar and others less so—with the idea that the legal system ought always to respect informed choice. which has predictable consequences for behavior. Behavioral economics is a form of economics. the possibility that some institutions—such as populist government—may be particularly bad at attempted correction of citizen error. the departures from the standard conception of the economic agent also alter behavior in predictable ways. Our principal emphasis is on how people respond to information and how this point bears on the role of law. Part I below offers a general framework and provides an overview of the arguments for enriching the traditional economic framework. offering a series of proposals that might seem surprising or controversial from a neoclassical economic perspective but that follow naturally from taking into account features of actual choice behavior. We suggest that many features of the legal landscape that are puzzling from a traditional law and economics perspective follow naturally from behavioral phenomena.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1475 “social welfare. Part III shifts to an explanation of existing legal rules and institutions. Just as people often have imperfect information. Parts II and III of the article involve positive analysis. we emphasize three broad points: the framework that behavioral economics suggests for thinking about issues of paternalism. Part II examines how a behaviorally-informed law and economics analysis can help to explain the behavior of human agents insofar as that behavior is relevant to law. We see this enrichment as similar in spirit to the increased emphasis on asymmetric information in mainstream economic analysis in recent decades. the ends of the legal system are more complex. Part IV of the article examines prescriptive issues. not to undermine it. that behavior is systematic and can be modeled. But from the perspective of behavioral economics. while others may be better. Behavioral economics does not suggest that behavior is random or impossible to predict.” usually measured by people’s revealed preferences. for the conventional economist. and also with the idea that government decisionmakers—who after all are behavioral actors too—can be relied upon to make better choices than citizens.

A. For a further elaboration of this view. in FOUNDATIONS OF RESEARCH IN ECONOMICS: HOW DO ECONOMISTS DO ECONOMICS? 227. FOUNDATIONS: WHAT IS “BEHAVIORAL LAW AND ECONOMICS”? In order to identify. Samuels eds. MITCHELL POLINSKY. Doing Economics Without Homo Economicus. Each of these bounds represents a significant way in which most people depart from the standard eco5. 1996). and its legal implications for markets and other institutions. Gary Becker offers a typical account of those principles: “[A]ll human behavior can be viewed as involving participants who [1] maximize their utility [2] from a stable set of preferences and [3] accumulate an optimal amount of information and other inputs in a variety of markets. and optimal processing of information. See. see Richard H. that general approach underlies a wide range of work in the economic analysis of law. Although some of Becker’s particular applications of the economic approach might be thought of as contentious. rational expectations. As we understand it. bounded willpower.”5 The task of law and economics is to determine the implications of such rational maximizing behavior in and out of markets.. GARY S. and bounded self-interest. . the defining features of behavioral law and economics. as we noted at the outset. it is useful first to understand the defining features of law and economics.7 People can be said to display bounded rationality. BECKER.6 What then is the task of behavioral law and economics? How does it differ from standard law and economics? These are the questions we address below.1476 STANFORD LAW REVIEW [Vol. POSNER. simply stated.. is to explore the implications of actual (not hypothesized) human behavior for the law. 50:1471 focus on debiasing rather than outright coercion) may be acceptable even if one thinks that citizen error is relatively unlikely. I. RICHARD A. e. ECONOMIC ANALYSIS OF LAW 3-4 (5th ed. Thaler. THE ECONOMIC APPROACH TO HUMAN BEHAVIOR 14 (1976). this has begun to change). but they are relatively unexplored in economics (although. Medema & Warren J. stable preferences. How do “real people” differ from homo economicus? We will describe the differences by stressing three important “bounds” on human behavior. bounds that draw into question the central ideas of utility maximization. Homo Economicus and Real People The task of behavioral law and economics. A. 1989). 6. AN INTRODUCTION TO LAW AND ECONOMICS 10 (2d ed. 230-35 (Steven G. 7. this approach to the law posits that legal rules are best analyzed and understood in light of standard economic principles. in a general way. 1998).g. All three bounds are well documented in the literature of other social sciences.

9. and in some cases because of these remedies.8 We have limited computational skills and seriously flawed memories. Herbert A. To deal with limited memories we make lists. minimizing the sum of decision costs and error costs. A Behavioral Model of Rational Choice. They also provide the foundations for new and sometimes quite formal models of behavior. To deal with limited brain power and time we use mental shortcuts and rules of thumb. While the heuristics are useful on average (which explains how they become adopted).. an idea first introduced by Herbert Simon. rules of thumb such as the availability heuristic—in which the frequency of some event is estimated by judging how easy it is to recall other instances of this type (how “available” such instances are)—lead us to erroneous conclusions. Bounded rationality. 1. 11 (Daniel Kahneman. As stressed in the pathbreaking work of Daniel Kahneman and Amos Tversky. Actual judgments show systematic departures from models of unbiased forecasts. and actual decisions often violate the axioms of expected utility theory. People can respond sensibly to these failings. for example. Bounded rationality. . in JUDGMENT UNDER UNCERTAINTY 3. and thus each of the three bears on generating sound predictions and prescriptions for law. The departures from the standard model can be divided into two categories: judgment and decisionmaking. that the probability of an event (such as a car accident) is greater if they have recently witnessed an occurrence of that event than if they have not. Nonetheless. Simon. thus it might be said that people sometimes respond rationally to their own cognitive limitations. Even when the use of mental shortcuts is rational. it can produce predictable mistakes. refers to the obvious fact that human cognitive abilities are not infinite. human behavior differs in systematic ways from that predicted by the standard economic model of unbounded rationality. While there are instances in which more than one bound comes into play. 69 Q. each of the three bounds points to systematic (rather than random or arbitrary) departures from conventional economic models.9 What is especially important in the work of Kahneman and Tversky is that it shows that shortcuts and rules of thumb are predictable.J. This means that someone using such a rule of thumb may be behaving rationally in the sense of economizing on thinking time. at this stage we think it is best to conceive of them as separate modeling problems. People tend to conclude. But even with these remedies. Judgment Under Uncertainty: Heuristics and Biases. they lead to errors in particular circumstances. but such a person will nonetheless make 8. Amos Tversky & Daniel Kahneman. 1982). Paul Slovic & Amos Tversky eds. A major source of differences between actual judgments and unbiased forecasts is the use of rules of thumb. 99 (1955).May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1477 nomic model. ECON.

as has been known since the early experiments by Allais and Ellsberg. conclude that expected utility theory performs fairly well. As Kenneth Arrow has explained. [A]ny coherent theory of reactions to the stimuli appropriate in an economic context . “[T]here is no general principle that prevents the creation of an economic theory based on other hypotheses than that of rationality. and the Savage Axioms. Hogarth & Melvin W. Reder eds. in RATIONAL CHOICE: THE CONTRAST BETWEEN ECONOMICS AND PSYCHOLOGY 201. called prospect theory.12 We emphasize that bounded rationality is entirely consistent with modeling behavior and generating predictions based on a model. 14. ECON. seems to do a good job of explaining many features of observed behavior. see Camerer.”13 Arrow’s example here is habit formation. in line with the methodology of conventional economics. in HANDBOOK OF EXPERIMENTAL ECONOMICS 587. . LITERATURE 669. Kenneth J. The model offered by Kahneman and Tversky. Id. John D. and so we draw on that model (whose main features we summarize in Part IV. 50:1471 forecasts that are different from those that emerge from the standard rationalchoice model. .B below) here. he says. Daniel Ellsberg.. This theory would strike many lay observers as plausible. 62 ECONOMETRICA 1291 (1994). the final bundle [of goods] purchased will not be the same as the initial [bundle]. While the axioms of expected utility theory characterize rational choice. For further discussion. Investigating Generalizations of Expected Utility Theory Using Experimental Data. Why Bounded Rationality?. 75 Q. Ambiguity. at 626-43. could in principle lead to a theory of the economy.J. An alternative to prospect theory for modifying expected utility theory is offered by Itzhak Gilboa & David Schmeidler. ECON. 622-24 (John H. For a survey of empirical tests of this and other models. it is different from utility maximization. for example. Individual Decision Making. 1987). Daniel Kahneman & Amos Tversky. Roth eds. 110 Q. 605 (1995).1478 STANFORD LAW REVIEW [Vol.10 Just as unbiased forecasting is not a good description of actual human behavior. Kagel & Alvin E. can be incorporated into a theory by supposing that people choose goods with an eye towards minimizing changes in their consumption. but they do not consider prospect theory as an alternative. ECON. Hey & Chris Orme. 671.. 619-20. if prices and income return to their initial levels after several alterations. 47 ECONOMETRICA 263 (1979). Arrow. 34 J. 13. 1995) (describing the Allais paradox). 12. See Colin Camerer. Rationality of Self and Others in an Economic System. . supra note 11. . .11 There has been an explosion of research in recent years trying to develop better formal models of actual decisionmaking. 682-83 (1996). . Case-Based Decision Theory. expected utility theory is not a good description of actual decisionmaking. yet it is not rational as economists have used that term. 202 (Robin M.14 10. Prospect Theory: An Analysis of Decision Under Risk. 11. actual choices diverge in important ways from this model. Risk. 643 (1961). that behavior. see the recent survey of results in John Conlisk. Though there is an optimization in this theory.J.

) Our notion is distinct from simple altruism. Weiss. and the bound operates in ways different from what the conventional understanding suggests. L. See Deborah M. 1275 (1991). we use the term bounded self-interest to refer to an important fact about the utility function of most people: They care. people often display bounded willpower. Most smokers say they would prefer not to smoke. and many pay money to join a program or obtain a drug that will help them quit. 899. consider “cooling off” periods for certain sales and programs that facilitate or even require saving.15 Thus. Bounded self-interest. we will draw on those models here. in some circumstances. As a result of these concerns. and they don’t keep tempting desserts around the house when trying to diet. As with bounded rationality. but rather the common assumptions about what that entails. we are not questioning here the idea of utility maximization. the demand for and supply of law may reflect people’s understanding of their own (or others’) bounded willpower. Formal models have been used to show how people deal with both fairness and unfairness. In some cases they may vote for or support governmental policies. people care about being treated fairly and want to treat others fairly if those others are themselves behaving fairly.16 Self-interest is bounded in a much broader range of settings than conventional economics assumes. POL. Douglas Bernheim. .May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1479 2. which conventional economics has emphasized in areas such as bequest decisions. (Thus. 99 J. even strangers. ECON. CHI. many people recognize that they have bounded willpower and take steps to mitigate its effects. the agents in a behavioral economic model are both nicer and (when they are not treated fairly) more spiteful than the agents postulated by neoclassical theory. Paternalistic Pension Policy: Psychological Evidence and Economic Theory. In many market and bargaining settings (as opposed to nonmarket settings such as bequest decisions). about others. or act as if they care. such as social security. 3. See B. How Strong Are Bequest Motives? Evidence Based on Estimates of the Demand for Life Insurance and Annuities. Bounded willpower. In addition to bounded rationality. to eliminate any temptation to succumb to the desire for immediate rewards. This term refers to the fact that human beings often take actions that they know to be in conflict with their own long-term interests. They join a pension plan or “Christmas Club” (a special savings arrangement under which funds can be withdrawn only around the holidays) to prevent undersaving. 899-900 (1991). Finally. 16. 58 U. REV. 15.

A. but not so spare that its predictions about behavior are often incorrect (as we will suggest is the case with conventional law and economics in some contexts).C). bounded rationality as it relates to decisionmaking behavior will come into play whenever actors are valuing outcomes. prior restraints on speech (Part III.A). Yuval Rottenstreich & Amos Tversky. mandatory contract terms (Part II. It also indicates the law and economics issues we analyze under each category.B).B). 25 J. When is each bound likely to come into play? Any general statement will necessarily be incomplete. Mark Kelman. The three bounds we describe do not (at least as we characterize them here) constitute a full description of human behavior in all its complexity. Although we will have more to say about parsimony below.C). 50:1471 4. Bounded willpower is most relevant when decisions have consequences over time. Second. Many interesting features of behavior discussed by psychologists but not emphasized by our framework may also play a role in explaining specific forms of behavior relevant to law. Our applications here include bargaining behavior (Part II. 93 MICH.B). LEGAL STUD.1480 STANFORD LAW REVIEW [Vol.B) and laws banning market transactions (Part III. . bounded self-interest (as we use the term) is relevant primarily in situations in which one party has deviated substantially from the usual or ordinary conduct under the circumstances. and risk assessments (Parts IV. Applications. but some broad generalizations can be offered. and risk assessments (Part IV. First. We discuss many examples below. Finally.. the endowment effect. 107 (1994) (finding effects of “equity seeking” and “reactive devaluation” on settlement behavior). we will say for now that our goal is to sketch out an approach spare enough to generate predictions across a range of contexts.D). bounded rationality as it relates to judgment behavior will come into play whenever actors in the legal system are called upon to assess the probability of an uncertain event.17 And it can be illuminating to attend in some detail to the role of social norms in 17. a prominent example here is loss aversion and its corollary. negligence determinations (Part IV. L. 287 (1996) (describing effects of “compromise” and “contrast” behavior on jury decisionmaking). The appendix summarizes some key features of each of the three bounds on human behavior just described. including environmental legislation (Part III.B and V.). where the benefits are generally immediate and the costs deferred.g. Russell Korobkin & Chris Guthrie.A). REV. e. our example is criminal behavior (Part IV. Context-Dependence in Legal Decision Making. The goal of this article is to show how the incorporation of these understandings of human behavior bears on the actual operation and possible improvement of the legal system. in such circumstances the other party will often be willing to incur financial costs to punish the “unfair” behavior. See. Psychological Barriers to Litigation Settlement: An Experimental Approach. which we discuss in connection with bargaining behavior (Part II.

For similar reasons. B. at 4. on these points. empirically documented phenomena that have reasonably precise implications for legal issues. Economics & Norms. There are few if any documented cases of Giffen goods (goods that are consumed more heavily at high prices. 4-6 (1962). valid. They also differ. 21. L. CHOOSING THE RIGHT POND (1985).May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1481 various contexts18 and to the place of shame. McAdams. 62 U. Richard H. 144 U. pride. See id. in their predictions about how law (as well as other forces) affects behavior. Law.J. Becker. quite conventional. however. FRANK. due to the fact that the price increase makes people unable to afford goods that are even pricier than the good in question).23 This 18. 1643 (1996). 20. See Symposium. and we will refer to these variables only occasionally and in passing. rather than to give full descriptions of individual motivations and self-understandings. consider the three “fundamental principles of economics” set forth by Richard Posner in his Economic Analysis of Law.20 in a discussion that is. 1 (1992). See Lawrence Lessig. such patterns would not generate distinct predictions (although they would of course matter to a full account of individual behavior). Relative Preferences. is to provide predictions. POL. we do not emphasize behavioral patterns that depart from standard economic assumptions but fail to point in systematic directions. 102 YALE L. . 943 (1995). REV. CHI. of course. in testable ways. Testable Predictions Behavioral and conventional law and economics do not differ solely in their assumptions about human behavior. L. As Becker has shown. Our focus here is robust. Gary S. McAdams’ work draws on ROBERT H. The Regulation of Social Meaning. even people choosing at random (rather than in a way designed to serve their preferences) will tend to consume less of a good when its price goes up as long as they have limited resources.22 This prediction is. To make these differences more concrete. However. See id. (Posner’s discussion represents an application of the basic economic methodology set forth by Becker above.19 especially insofar as an understanding of these variables helps give content to people’s utility functions in ways that bear on the uses of law. Irrational Behavior and Economic Theory. 1. 22. POSNER. 19. supra note 6.21) To what extent would an account based on behavioral law and economics offer different “fundamental principles”? The first fundamental principle for the conventional approach is downward-sloping demand: Total demand for a good falls when its price rises. 23. and status. Our principal purpose here. PA. confirmation of the prediction of downward-sloping demand does not suggest that people are optimizing. ECON. 70 J. at 3. REV.

The traditional assumption about sunk costs also generates invalid predictions. 1327 tbl.27 the decision would be made purely on the basis of the benefits and costs from that moment forward. to go out” on the evening of a particular performance. Here is one: A theater patron who ignores sunk costs would not take into account the cost of a prepaid season pass in deciding whether to “rou[se] [him]self . and they will ignore sunk costs (costs that cannot be recovered. . But each of these propositions is a frequent source of predictive failures. Thaler. Experimental Tests of the Endowment Effect and the Coase Theorem. the opportunity to sell one’s possessions) to out-of-pocket costs (such as costs incurred in buying possessions). 7. in a study of theater patrons. some of whom were randomly assigned to receive discounted prices on prepaid passes. the patrons who received discounts were found to attend significantly fewer performances than those who did not receive discounts. POSNER. evidence of downward-sloping demand is not evidence in support of optimizing models. . despite the fact that (due to random assignment) the benefit-cost ratio that should have mattered—benefits and costs going forward—was the same on average 24. such as the cost of nonrefundable tickets). estimates of the ratio of selling prices to buying prices are often at least two to one. 24-25 (1995). ECONOMIC CHOICE THEORY: AN EXPERIMENTAL ANALYSIS OF ANIMAL BEHAVIOR 8. decisionmakers will equate opportunity costs (which are costs incurred by foregoing opportunities—say. Indeed. POL. 98 J. See Daniel Kahneman. at 6. yet would also be unwilling to sell at this price.”25 Thus. 25. these results are just what behavioral analysis suggests. yet the size of the transaction makes it implausible in these studies to conclude that wealth effects explain the difference. according to traditional analysis. Jack L. 17-19. 50:1471 behavior has also been demonstrated with laboratory rats. supra note 6.’” and “‘[s]unk’ (incurred) costs do not affect decisions on prices and quantity. as is well known. in the absence of important wealth effects. ROBERT NOZICK. buying prices will be roughly equal to selling prices.24 Thus. ECON. THE NATURE OF RATIONALITY 22 (1993).1 (1990) (summarizing studies).26 As described below. The equality of opportunity costs and out-of-pocket costs implies that. . 1325. 26. JOHN H. This is frequently violated. The second fundamental principle of conventional law and economics concerns the nature of costs: “Cost to the economist is ‘opportunity cost. Many people holding tickets to a popular sporting event such as the Super Bowl would be unwilling to buy tickets at the market price (say $1000). 27. However. Knetsch & Richard H. KAGEL. RAYMOND C. BATTALIO & LEONARD GREEN.1482 STANFORD LAW REVIEW [Vol.

Careful empirical study. Here behavioral analysis generates a prediction distinct from standard economic analy28. Half the students were endowed with tokens. those without tokens should (and do) buy tokens if they can get one at a price below their assigned value. if there were really no transaction costs (and no wealth effects). 3 J. supra note 26. 29. it can lead to inaccurate predictions. Those with tokens should (and do) sell their tokens if offered more than their assigned value.32 let us offer an interpretation geared to the particular context of economic analysis of law. initial entitlements alter the final allocation of resources. & ECON. See id. R. The Problem of Social Cost. BEHAV. Markets were conducted for tokens. The subjects were forty-four students taking an advanced undergraduate course in law and economics at Cornell University.28 In short.31 That is. sunk costs mattered. The equilibrium price was always exactly what the theory would predict. Each student (whether or not endowed with a token) was assigned a personal token value. identical to the first except that now half the students were given Cornell coffee mugs instead of tokens. life is generally not about tokens redeemable for cash. See Kahneman et al. The third fundamental principle of conventional law and economics is that “resources tend to gravitate toward their most valuable uses” as markets drive out any unexploited profit opportunities. this yields the Coase theorem—the idea that initial assignments of entitlements will not affect the ultimate allocation of resources so long as transaction costs are zero. again. however.H. POSNER. & HUM. supra note 6. Coase. shows that the Coase theorem is not a tautology. 30. and if an alternative allocation of resources would make some agents better off and none worse off. DECISION PROCESSES 124. 127-28 (1985). and the tokens did in fact flow to those who valued them most. Arkes & Catherine Blumer. 32. the standard prediction proved invalid.30 Many economists and economically oriented lawyers think of the Coase theorem as a tautology. these assigned values induce supply and demand curves for the tokens. then of course the agents would move to that allocation. while those with tokens could sell. 31. at 1329-42. Thus another experiment was conducted. L.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1483 in the two groups. The Psychology of Sunk Cost. Hal R. indeed. However. These token markets are a complete victory of economic theory. 35 ORG.29 When combined with the notion that opportunity and out-of-pocket costs are equated (see fundamental principle two). which emphasizes the difference between opportunity and out-of-pocket costs. at 11. even when transaction costs and wealth effects are known to be zero. 1 (1960). Those without tokens could buy one.. . Consider the following set of experiments conducted to test the Coase theorem. These results are predicted by behavioral economics. the price at which a token could be redeemed for cash at the end of the experiment.

Unlike the case of the tokens. Was this prediction correct? Yes. willpower. outcomes can diverge substantially from those predicted by economic theory. we offer some examples below. Even naive subjects participating at low stakes produce outcomes indistinguishable from those predicted by the theory when trading for tokens. And those who were endowed with mugs asked more than twice as much to give up a mug as those who didn’t get a mug were willing to pay. The foregoing discussion illustrates the point with which we began this section: The difference between conventional and behavioral law and economics is not just a difference in the validity of the assumptions about human behavior. . when agents must determine their own values (as with the mugs). even in the mugs markets. These lessons can be applied to other markets. While the assumptions of unbounded rationality. First. fewer trades for mugs than for tokens). That is. there was just not as much trading as the theory would predict. even when they exist and have considerable importance. and mugs were randomly distributed). those endowed with mugs should be reluctant to part with them even at prices they would not have considered paying to acquire a mug had they not received one. in ESSAYS IN POSITIVE ECONOMICS 3. instead only fifteen percent of the mugs traded. there was trading. markets are indeed robust institutions. Markets were conducted and mugs bought and sold. What are we to make of these findings? There are at least three important lessons. the force of behavioral economics comes from the difference in its predictions (for example. In this sense.33 We share this view (or at least will accept it for purposes of this arti33.1484 STANFORD LAW REVIEW [Vol. these departures will not be obvious outside an experiment. our analysis is consistent with the precept originally proposed by Milton Friedman: Economics should not be judged on whether the assumptions are realistic or valid. This effect is generally referred to as the “endowment effect”. Whereas the Coase theorem would have predicted that about half the mugs would trade (since transaction costs had been shown to be essentially zero in the token experiments. The students who were assigned mugs had a strong tendency to keep them. but rather on the quality of its predictions. The Methodology of Positive Economics. Third. and self-interest are unrealistic. 14-16 (1953). the assignment of property rights had a pronounced effect on the final allocation of mugs. See MILTON FRIEDMAN. 50:1471 sis: Because people do not equate opportunity and out-of-pocket costs for goods whose values are not solely exogenously defined (as they were in the case of the tokens). it is a manifestation of the broader phenomenon of “loss aversion”—the idea that losses are weighted more heavily than gains—which in turn is a central building block of Kahneman and Tversky’s prospect theory. This result did not change if the markets were repeated. Second.

That is. no plausible value of risk aversion could explain such a big difference. BONDS. there are often significant costs of arbitrage in equity markets. 35. As predicted by this theory. 111 Q.37 Although the theory gets the sign right in this case. See Jeffrey Pontiff. PERSP. Prescott. See Jeremy J. (3) the positive correlation in financial markets between risk and expected return. as with tests of downward-sloping demand curves. C. Unfortunately. 192. . 11 J. See POSNER. supra note 6. for a discussion. 37. at 191. which we discuss just below.”35 The equity premium is the difference in returns between equities and riskless assets.. stocks (equities) earn higher returns (on average) than do riskless assets such as treasury bills. Anomalies: The Equity Premium Puzzle.34 The problem with the first three examples is that. Andrei Shleifer & Robert W. ECON. for the theory may misstate the magnitude of the effect. Mehra and Prescott therefore ask whether it can possibly be explained by investor risk aversion. The Equity Premium: A Puzzle. 35 (1997). Thaler. Costly Arbitrage: Evidence from Closed-End Funds. (And note that arbitrage. But what can we say about the magnitude? Is this difference in return roughly what the theory would predict? This is precisely the question posed by Rajnish Mehra and Edward Prescott in their well-known paper on the “equity premium puzzle. they are quite undemanding. MONETARY ECON. Partial and Ambiguous Successes of Conventional Economics What of all the well-known successes of conventional economics? Do they show that predictions about law based on the conventional assumptions tend to work? Consider some examples of the successes: (1) the inverse correlation between price ceilings and queues. STOCKS. The Limits of Arbitrage. 15 J. would not be expected to eliminate the equity premium. Vishny. at 18. they ask simply whether the theory gets the direction of the effect right—and it does. See IBBOTSON ASSOCIATES.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1485 cle). Siegel & Richard H. FIN. Rajnish Mehra & Edward C. the positive relation between risk and return in financial markets. the equity premium has been roughly six percent per year over the past seventy years. they often do not. (2) the inverse correlation between rent control and the stock of housing. In the United States. as we have emphasized. Winter 1997. 38. But this is not a complete vindication of the theory. the magnitude of the effect suggests that the theory is wrong. 145 (1985). while a dollar invested in treasury bills would have accumulated to less than $15. 36. Consider (3). ECON. 1135 (1996). be worth over $1800. (4) the relation between futures prices and spot-market prices. A behavioral analysis would be of much less interest if conventional economic models did a satisfactory job of predicting the behavior of agents insofar as relevant to law. This difference is remarkably large. our principal interest is predictive in character. at the end of 1997. 52 J. BILLS AND INFLATION: 1997 YEARBOOK.38) 34.J.36 This implies that a dollar invested in stocks in 1926 would. They conclude that it cannot.

the relation between spot and futures contracts for foreign exchange are good forecasts of movements in exchange rates. the markets in which these professionals operate offer frequent opportunities for learning. then investors can make sure profits by buying the contract that is too cheap and selling the one that is too expensive. and except possibly for organized crime. First. it suggests that while human beings often display bounded rationality. . those who engage in low-payoff activities lose utility but do not create profit opportunities for others. Thaler. If spot and futures prices get out of line. THALER. THALER. The Relevance of Quasi Rationality in Competitive Markets.1486 STANFORD LAW REVIEW [Vol. 248-49 (1991). 185-86 (1992). See Kenneth A. However. 41. such as futures trading. Criminal Law and the Optimal Use of Nonmonetary Sanctions as a Deterrent. QUASI RATIONAL ECONOMICS 239.” Finally. the decision to enter a life of crime is not one that is made 39. Outside of financial markets (and not always there). and self-interest. So. does better on magnitudes. Foreign Exchange. arbitrage is possible. See. THE WINNER’S CURSE: PARADOXES AND ANOMALIES OF ECONOMIC LIFE 182. The point is important. in RICHARD H. Froot & Richard H. Under these circumstances. See Thomas Russell & Richard H. in RICHARD H. then there is no way for anyone else to profit directly from his behavior. 85 COLUM. Consider the proposition that a potential criminal will commit some crime if the expected gains from the crime exceed its expected costs.41 Suppose a criminal mistakenly thinks that the expected gains outweigh the expected costs. First notice that no arbitrage will be possible in this situation. 50:1471 Example (4) above.) Being a bad criminal is rarely fatal. 1232. For example. e. If someone is unfortunate enough to commit a crime with a negative expected value. willpower. Second. Then the question becomes when. Third. when in fact the opposite is true. these forecasts are systematically biased. this case is special in several respects. 40. consider GM. L. in some (fairly unusual) circumstances. REV. Thaler. do market forces make it reasonable to assume that people behave in accordance with those assumptions? What circumstances apply to most of the domains in which law and economics is used? In this regard it is instructive to compare the market for futures contracts with the market for criminal activity. this context is one in which most of the activity is undertaken by professionals who will quickly lose their money and their jobs if they make frequent errors. markets can sometimes lead to behavior consistent with conventional economic assumptions. 1235 (1985). Nor do they typically disappear from the market.g. there is little opportunity for “hostile takeovers. Spot and futures prices are very closely related. markets tend to work very well. market forces are strong enough to make the three “bounds” irrelevant for predictive purposes. (Even poorly run firms can survive for many years. Steven Shavell.39 though not perfectly. in a rational market.40 Essentially. these conditions render agents who do not conform to the standard economic assumptions irrelevant (because they will be bankrupt). In fact. the relation between spot and futures prices.. exactly.

Once a teenager has dropped out of high school to become a drug dealer. is to take the core insights and successes of economics and build upon them by making more realistic assumptions about human behavior. One cannot look at the current state of antitrust law. In fact. We wish to retain the power of the economist’s approach to social science while offering a better description of the behavior of the agents in society and the economy. and perhaps that picture will make prediction more difficult. But conventional . it would be highly desirable to come up with a model of behavior that is both simple and right. as we see it. in short. or the use of market-based regulation in environmental law (to name just two of many examples). offers the potential to be law and economics with a higher “R2”—that is. Everything can be explained in an ex post fashion—some tool will be found that is up to the task—but the elegance. Shouldn’t analysts proceed with simple tools? We offer two responses: First. We will try to highlight some of that potential (and suggest cases where it has been realized) in this article. Because law and economics is frequently applied to criminal behavior. so special care should be taken not to push the standard economic model too far. it is difficult to switch to dentistry.) The project of behavioral law and economics. generalizability. a behavioral perspective offers a more complicated and unruly picture of human behavior. those who would argue that rent control helps tenants must contend with the obvious long-run supply effects of such laws.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1487 repeatedly with many opportunities to learn. At least—the objection goes—it provides a theory. greater power to explain the observed data. By contrast. and predictive power of the economic method will be lost. This is by no means to say that conventional law and economics has had no victories. economic analysis of law seems to be a branch of economics in which the limits of arbitrage are particularly powerful. Parsimony A possible objection to our approach is that conventional economics has the advantage of simplicity and parsimony. precisely because behavior is more complicated and unruly. simplicity and parsimony are indeed beneficial. D. Attention to incentive effects can often reveal a great deal. Many advances in the positive and prescriptive understanding of law have come from the conventional assumptions. We think that the same analysis applies to many of the domains in which law and economics has been used. Behavioral law and economics. Often this approach points in the right direction and identifies flaws in noneconomic reasoning. without acknowledging the important advances produced through the conventional approach. (Thus. the above argument is obviously germane.

the term “rationality” is highly ambiguous and can be used to mean many things. Mark Perlman & Christian Schmidt eds. that is.42 Indeed. behavioral research shows that people sometimes behave in an inconsistent manner by. See. PHILLIPSON & RICHARD A.” in which choices define preferences. We observe departures from most of these definitions. or (5). thus. or (5) is effective in achieving her goals. but Y over X if asked to give their willingness to pay for each option. Social Norms and Social Roles. The person who drinks castor oil as often as possible is rational because she happens to love castor oil.) can be explained on similar grounds. to the extent that conventional economics achieves parsimony. L. 50:1471 economics is not in this position.. See Cass R. indicating a preference for X over Y if asked to make a direct choice. POSNER. Rational Theory and Constructive Choice. 96 COLUM. 1996). . if the actor changes her behavior when the costs and benefits are altered. without some specification of what counts as a cost and a benefit. 45. PRIVATE CHOICES AND PUBLIC HEALTH: THE AIDS EPIDEMIC IN AN ECONOMIC PERSPECTIVE 4 (1995). to generate predictions it must be more fully specified. Thus the idea is ambiguous between the notion of “revealed preferences.. 44. suicide. in THE RATIONAL FOUNDATIONS OF ECONOMIC BEHAVIOUR 185. Second. TOMAS J. whatever the relationship between those goals and her actual welfare.46 42. (4) promotes her own welfare. 43. for its predictions are often wrong.g. 46. Arrow. 189-91 (Kenneth J. (3) is internally consistent. for example. REV. By itself the notion of “rationality” (the centerpiece of traditional analysis) is not a theory. A person might be deemed rational if her behavior (1) conforms to the axioms of expected utility theory. Enrico Colombatto. Its goal is to provide a unitary theory of behavior. Other self-destructive behavior (drug addiction. Sunstein. (2) is responsive to incentives. often through the use of auxiliary assumptions. etc.1488 STANFORD LAW REVIEW [Vol. the idea of responsiveness to incentives is empty. As for (2). people’s decisions sometimes do not promote their welfare or help them to achieve their own goals.44 Many of our examples will thus show that people are frequently not rational if the term is understood to mean (1). 903. It is not even clear on this view whether rationality is intended as a definition of “preference” or as a prediction. and the notion of a maximization function that lies behind and helps explain choices. it often does so at the expense of any real predictive power. 931-38 (1996). If rationality is used to mean simply that people “choose” what they “prefer” in light of the prevailing incentives. and with respect to (3). Both notions raise many difficult issues. supra note 13.45 then the notion of rationality offers few restrictions on behavior.43 With respect to (4) and (5). Amos Tversky. We will encounter many examples in addition to those already discussed. (4). See notes 11-12 supra and accompanying text. and prospect theory seems to predict behavior better. scholars have documented departures from expected utility theory for nearly fifty years. e. with respect to (1). See Arrow. at 205-06. a goal which may be impossible to achieve. (3).

What follows should be taken partly as a proposal. A useful first example of this bound is agents’ behavior in a very simple bargaining game called the ultimatum game. (“Fairness” is not. but to show the promise of behavioral economics in casting light on a wide range of questions. that more people voted simply because voting seemed especially valiant in those circumstances (so much for predictions based on this form of rationality). The Ultimatum Game 1. what does the assumption predict? Does it merely predict that people will respond to changes in conditions—for example. we believe. on this view. the Pro- . II. the third bound described above. perhaps in the spirit of the early economic analysis of law. after an unusually large vote amidst the storm. A theory with infinite degrees of freedom is no theory at all. For example. For example. In this game. The game and its sunk-cost variation. BEHAVIOR OF AGENTS A. the prediction is not bad. in the case of “fairness. We believe that a behavioral approach imposes discipline on economic theorizing because assumptions cannot be imported at will. fewer people will vote when it is snowing? If so. In a behavioral approach.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1489 If such a notion of rationality allowed for good predictions. however. but those predictions are often inaccurate. and those forms provide stronger predictions in some cases. Our purpose is not to settle all of them. so much the worse for the rationality assumption. We begin with bounded self-interest. if it is not a paradox.” specifically defined and empirically verified patterns of behavior are used to generate predictions in new contexts. A great deal of work would be necessary to justify authoritative judgments on most of these questions. one player. This approach. We now turn to positive.) This is the approach we advocate for economic analysis of law. is that so high a degree of flexibility leaves the theory with few a priori restrictions. simply a catch-all to explain any observed behavior. produces a better understanding of law and a better set of predictions about its effects. and normative issues. prescriptive. If it is a paradox. consider whether it is a paradox (as many economists think) that so many people vote (despite the virtual certainty that no one person’s vote will alter the outcome). but surely it would be possible to say. Conventional economics sometimes turns to stronger forms of rationality in response. assumptions about behavior should accord with empirically validated descriptions of actual behavior. the problem. as described above and as illustrated by the examples considered below. for a research agenda to be carried out with a new set of tools. then perhaps there would be no reason for complaint.

) We do not see behavior moving toward the prediction of standard economic theory. Anomalies: Ultimatums.49 (Of course. Daniel Kahneman. Spring 1995. An Experimental Analysis of Ultimatum Bargaining. since a penny is better than nothing. at S291 tbl. 588 fig. 3 J. supra note 47. 865. What would happen if the stakes were raised substantially. ECON. however.3A. Economic theory has a simple prediction about this game. the average minimum amount that Responders say they would accept is between twenty and thirty percent of that sum. . at 573. 375 tbls. 210-11. ECON. supra note 47. Roth. The Proposer will offer the smallest unit of currency available.000. or he can reject the offer. 66 ECONOMETRICA 569. Thaler. and the Responder will accept. Vesna Prasnikar & Alvin E. supra. To a first approximation. This is a form of bounded self-interest.J. 367. even at a financial cost to themselves. 873-75 (1992). is asked to propose an allocation of a sum of money between herself and the other player. as we learned in a study conducted for this 47. S291 tbl..1490 STANFORD LAW REVIEW [Vol.2. 9 J. although they are still far above what the standard analysis would predict. the Responder. the factors that many economists thought would change the outcome of the game did not. He can either accept the amount offered to him by the Proposer.000. so reputations and future retaliation are eliminated as factors. PERSP. Roth. 49. Raising the stakes from $10 per pair to $100. When repetition is combined with very high stakes. Fairness and the Assumptions of Economics. they typically offer a substantial portion of the sum to be divided—ordinarily forty to fifty percent. Considerations of Fairness and Strategy: Experimental Data from Sequential Games.47 Responders are thus willing to punish unfair behavior. leaving the rest to the Proposer. say a penny. neither of these factors changes the results in any important way. Neither player knows the identity of his or her counterpart. Robert Slonim & Alvin E. and the players will play against each other only once. ECON.2 (1986). See Werner Güth. BUS. or the game was repeated several times to allow learning? In this case. See Slonim & Roth.4 & 5. 59 J.. we know the answer. 573 (1998).4 & 5 (1982). But. This turns out to be a very bad prediction about how the game is actually played. and Manners. 371-72. the same is true of repeating the game ten times with different partners. at 209. in which case both players get nothing. 107 Q. Knetsch & Richard H. Jack L. or even to more than a week’s income (in a poor country) has little effect. Rolf Schmittberger & Bernd Schwarze. 50:1471 poser. See Colin Camerer & Richard H. 375 tbls. Dictators. offers decrease somewhat. at 371-72. And this response seems to be expected and anticipated by Proposers. 48. Kahneman et al. & ORG.. Responders typically reject offers of less than twenty percent of the total amount available. Thus. at some point raising the stakes would matter. See Güth et al. Learning in High Stakes Ultimatum Games: An Experiment in the Slovak Republic. S285. Thaler. probably few people would turn down an offer of five percent of $1. The Responder then has a choice. BEHAV.48 Economists often worry that the results of this type of experiment are sensitive to the way in which the experiment was conducted.

when the $10 to be divided was provided to subjects by the experimenter. which the bargainers forfeit if the Proposer’s offer is rejected). 61% of the MIT students demanded at least $4.00. and 32% demanded a full refund of their $5. we anticipated that Responders would feel that they had an “entitlement” to the $5 they had contributed to the experiment and would therefore be reluctant to accept less. Although economic theory says that the sunk-cost variation of the ultimatum game will have no effect on behavior (since the $5 collected from each student is a sunk cost and should therefore be ignored by the players). we predicted that in this domain sunk costs would matter. The UC Law students were slightly less extreme: 47% demanded at least $4. the average demand was $3.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1491 article.94. does have an effect. Students were given a form asking them how they would play both roles in an ultimatum game in which the $10 to be divided was contributed half by the Proposer and half by the Responder. Do sunk costs alter behavior in the ultimatum game? To find out. 50.00. 67% demanded at least $4.” we conducted another experiment right after in which the winner of a game was awarded any profits earned by the experimenter in the first round. This is precisely what we found. Each of these means is significantly different from the control value of $1. and 23% demanded $5.21 for a group of MIT MBA students. In the sunk-cost version. but in fact decisionmakers often do not behave in this way. and $3. so they had to decide first what offer to make if they were chosen to be a Proposer and then what minimum offer they would be willing to accept if they were a Responder. $3. To solve this “problem. In the original version of the game. economics predicts that decisionmakers will ignore sunk costs in making their choices (see fundamental principle two above).94 under any conventional measure of statistical significance. namely the introduction of a sunk cost. a factor that economic theory predicts will not have an effect.00. Looking past means. where the students each paid $5 to participate. For UC MBA students. As noted above. and 40% demanded $5.00.73 for a group of University of Chicago (UC) MBA students. . This experiment is profitable for the experimenter if any offers are rejected by Responders (because the experimenter has collected $10 from each pair of bargainers. we asked classroom volunteers to bring $5—what would become a sunk cost for them—to class.35 for a group of UC Law students.00.00. In particular. They were told that their role would be determined by chance.50 We also ran a version of the standard ultimatum game (without sunk costs by the students) as a control. the average minimum amount demanded by Responders was $1.

Many of Robert Ellickson’s examples in his pathbreaking book. however. allowing one to test directly for fairness. cannot be explained on grounds of reputation. 437 (1993). for example. presumably at some cost to the remaining firms. ECON.00 32% 40% 23% MIT MBA UC MBA UC Law Note that our emphasis here.52 The fairness results obtained in various experimental settings.1 (1996) (finding that Proposers typically offered no more than 10% of the sum to be divided—and over 60% offered nothing—when (1) the Responder had no choice but to accept the Proposer’s offer and (2) anonymity was guaranteed). The parties are interacting anonymously and in a one-shot fashion. 653. Does Fairness Prevent Market Clearing: An Experimental Investigation. Order Without Law. firms that violate the norms of an industry are ostracized. ROBERT C. not on affirmative concerns for fairness on the part of Proposers. their behavior appears fully consistent with financially maximizing responses to Responders’ fairness behavior.51) We do know. partly because of a rational fear that the offending party might be untrustworthy. other experimental results support this conclusion. 653-54 & fig. even when the punishment is costly to administer (as when Responders turn down small offers).73 $3. (As noted above.53 Often it is impossible to disentangle the two effects. Social Distance and OtherRegarding Behavior in Dictator Games. The value of the experimental method is precisely that situations can be created in which the reputational factor is absent (because the transactions are anonymous and one-shot). is on the fairness behavior of Responders.J. 108 Q. REV. many real-world situations may reflect a combination of reputational and fairness factors. Thus. See Elizabeth Hoffman. 86 AM. Kevin McCabe & Vernon L. Smith. Thus. 53. and partly because of a spiteful tendency to punish unmannerly behavior.35 Percent Demanding $4. ORDER WITHOUT LAW (1991). ECON. 50:1471 ULTIMATUM GAME RESULTS Average Demand $3. 51. for instance. The ultimatum game results show that we find it: People will often behave in accordance with fairness considerations even when it is against their financial self-interest and no one will know.00 61% 67% 47% Percent Demanding $5.1492 STANFORD LAW REVIEW [Vol. ELLICKSON. See Ernst Fehr.21 $3. that in other contexts people appear to display affirmative concerns for fairness. Of course. 52. Georg Kirchsteiger & Arno Riedl. such as the ultimatum game. as well as in the ordinary ultimatum game. . have precisely this flavor.

The box has just a small slit. 1920. Similarly. supra note 40. is a more complicated story of reciprocal fairness. so no one can (easily) make off with the money. not taken out. The farmers also know that if it were easy to take the money. Thaler & Robyn M. common to most economic theorizing. It is also no answer to say that the results of the ultimatum game are readily predictable on the conventional model on the ground that pride and self-conception are part of players’ utility functions. most people driving by a farm do not pull over and stuff two dollars through the mail slot. Fairness. we observe not only apparently “nice” behavior (generous offers) but also “spiteful” behavior (Responders turning down small offers at substantial cost to the Proposers). First of all. so money can only be put in. We think that the farmers who use this system have just about the right model of human nature. How can economic analysis be enriched to incorporate the behavior observed in the ultimatum game and its sunk-cost variant? As we have indicated. ex post additions to the 54. Cooperation. someone would do so. and customers are expected to put money in the box in return for the vegetables they take. Also. in contrast. They feel that enough people will volunteer to pay for the fresh corn to make it worthwhile to put it out there. of “unbounded self-interest. and Responders should accept. What reason is there to believe that these people care about one another? (Most of us give little of our wealth to anonymous strangers whom we have no reason to believe are any worse off than we are. even in Ithaca.54 We emphasize that this is not a story of simple altruism. at 6. Fairness behavior is probably reciprocal. cannot readily be explained on grounds of simple altruism. like the behavior of the Ithaca shoppers. . The problem with this view is not that it is false but that it allows ad hoc. In the ultimatum game. and scruples. Richard H. in THALER.” This assumption implies that Proposers should offer the smallest sum possible. the box is attached to the table. Theoretical considerations. There is a cash box on the table. acrimony. Dawes. people appear simultaneously nicer and more spiteful than conventional assumptions predict. 2. our account. the first step is to relax the assumption.) Second. the games are played between anonymous strangers. A concern for fairness is part of most agents’ utility function. An alternative view is offered in the following account: In the rural areas around Ithaca it is common for farmers to put some fresh produce on a table by the road. such altruism is sometimes recognized in conventional economics.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1493 most people leave tips in out-of-town restaurants that they never plan to visit again. As noted above. The results of the ultimatum game.

55. these desires compete with others in a world of scarce resources. and in addition they have preferences about (c) the well-being of some strangers whose interests are at stake. We don’t recommend that Mercedes dealers adopt the road-side stand selling technique. in such a way as to deprive the conventional model of the ability to make any predictions. Matthew Rabin. The sort of balanced conception of human nature suggested by the ultimatum game results and the practices of farmers in Ithaca need not be informal or ad hoc. (d) their own reputation. and (e) what kind of person they wish to be. A person’s willingness to cooperate or to help others can be seen as a function of these variables. REV. ROBERT AXELROD. 57. people are willing to sacrifice their own material well-being to help those who are being or have been kind. Generalizing from Rabin’s treatment. 56.1494 STANFORD LAW REVIEW [Vol. bearing on the appropriate role of law. ROBERT AXELROD. An elegant formal treatment is offered by Matthew Rabin in a model of fairness. at 1282.57 Rabin’s theory can be viewed as a theory of manners and principles. 1281 (1993). Stated simply and nonformally: (A) People are willing to sacrifice their own material well-being to help those who are being kind. such as the desire to be fair (to those who have been fair) and also to be spiteful (to those who have not been fair). the desire to think of yourself as an honest. principled person helps explain why most of us (though not all) do leave tips in strange restaurants and would leave money in the box at the road-side stand. we might say that people can be understood as having preferences for (a) their own material payoffs and (b) those of some others they know well. 83 AM. Of course. 50:1471 utility function. (B) People are willing to sacrifice their own material well-being to punish those who are being unkind.55 Rabin’s framework incorporates three stylized facts about behavior. Incorporating Fairness Into Game Theory and Economics. . ECON. Related work.56 Rabin shows how these assumptions about behavior can explain the behavior observed in the ultimatum game as well as other games of cooperation such as the Prisoner’s Dilemma. THE COMPLEXITY OF COOPERATION (1997). The last factor is important and especially easy to overlook. THE EVOLUTION OF COOPERATION (1984). As Rabin says. Id. in a rigorous analysis. (C) Both motivations (A) and (B) have a greater effect on behavior as the material cost of sacrificing becomes smaller. The goal of the behavioral approach is to go back and forth between data and theory to generate predictions that will generalize. has shown the role of such behavior in helping to produce norms that solve collective action problems. It is possible to incorporate material and nonmaterial motives.

where. Under these circumstances. unfortunately. spiteful behavior—such as rejection of small offers in the ultimatum game—is typically observed in situations 58. Retribution and Related Concepts of Punishment. in the role of Responder in the ultimatum game playing against his soon-to-be-ex-spouse. A loss to another is a gain to oneself. 9 J. even when the small offer is a substantial amount of money. (Divorces that end up in court are. to reject low offers. and after litigation. these are the conditions for spite. 59. the hurting. material or otherwise. Cf. such as during a fight or argument. 71 (1980). during. Sometimes the fact that another person will lose. This is the same behavior that drives boycotts. in a material or other sense. Much protracted litigation— cases that fail to settle early and amicably—may arise precisely because the two sides were unable to deal with matters in a more friendly manner.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1495 Thus behavioral economic agents have manners and scruples that can lead them to be “nice” in some settings. The concepts of revenge and retribution. acrimony is particularly prevalent in many legal settings. for example. 16. it may often be quite relevant. almost by definition. even the idea of thinking of oneself as a certain kind of person (not a doormat or a dupe) can lead in the direction of inflicting losses. Notice that this spiteful behavior is also “principled”: People are willing to pay to punish someone who has been unfair. is a benefit to the agent. as we observe in the ultimatum game. but it has received little attention in law and economics. under bad conditions. Robert Gibbons & Leaf Van Boven. 1997) (unpublished manuscript. not wanting the Proposer to benefit greatly. Thus Responders who receive (relatively) small offers are willing to decline them in order to punish the rude Proposers who tried to grab too much for themselves. have been discussed by Posner. LEGAL STUD. is part of the agent’s gain. (Concern with not establishing a reputation as a doormat or a dupe may also play a role. Posner. Multiple Selves in the Prisoners’ Dilemma (Nov.) We suspect that spiteful behavior is frequently observed in conditions of acrimony even when reputational concerns are unimportant.58 Spiteful behavior is common under conditions of acrimony. even married couples will say and do things to hurt the other party. which are related to spite.59 What is “fair”? Absent acrimony. Conventional economics has sometimes recognized such behavior. where consumers refrain from buying something they normally enjoy in order to punish an offending party. on file with the Stanford Law Review) (finding that subjects are more likely to engage in cooperative behavior in games when they have a positive impression of their opponent than when they have a negative impression). But. people can also be provoked to be spiteful. acrimonious. . An agent may calculate that the costs of benefiting another person argue strongly against a deal. See Richard A.) This is of course the converse of circumstances of cooperative behavior. we think that the average contestant in a divorce case that ends up in court would be likely. Unfortunately. before. even if the agent would benefit materially.

at 729-30.63 Norms. See Daniel Kahneman.60 When the interactions are between bargainers dividing a sum of money to which neither is more entitled than the other (and this is common knowledge). REV. Thus far the discussion has emphasized fairness. See Elizabeth Hoffman & Matthew L.61 And if the parties are a consumer and a firm in the market. supra note 60.62 We will have much more to say about this last context in Part III below. restaurants. recycling. Entitlements. A better understanding of the ingredients of individual utility could help a great deal with both the positive and prescriptive analysis of law. For now our goal is simply to offer our general definition of what is “fair” and to make clear that we do not view the term as a vague and ill-defined catch-all. and automobiles. through purchasing books. 729-30 (1986). in contrast to the more market-oriented contexts we consider. & ECON. L. LEGAL STUD. it might help us understand more about (and be better able to predict in related contexts in the future) the massive changes 60. most people regard an offer of. we view it as having a reasonably well-specified meaning that can generate useful predictions across a range of contexts. the “reference transaction” is something like an equal split. 17 INT’L REV. Spitzer. punished by Responders. 728. . accordingly. 259. the “reference transaction” is a transaction on the usual terms for the item in question. Jack L. discriminating on the basis of race and sex. at 582.” This raises an obvious question: What is “fair”? In the ultimatum game. See Kahneman et al. id. Rights. 575 (1997). suits. then the “reference transaction” is a split that favors the more-entitled party. because. a penny to the Responder as “unfair. vacation spots. 261 (1985). But fairness-related norms are a subset of a large category of norms that govern behavior and that can operate as “taxes” or “subsidies. Knetsch & Richard Thaler. say. or through smoking. Rather.” as Lando ultimately concludes. 76 AM. ECON.” This perception is an illustration of a more general pattern: People judge outcomes to be “unfair” if they depart substantially from the terms of a “reference transaction”—a transaction that defines the benchmark for the parties’ interactions. and Fairness: An Experimental Examination of Subjects’ Concepts of Distributive Justice. there is no clear “reference transaction” in the tort context. For a recent effort to incorporate a more general notion of “fairness” into the economic analysis of tort law. substantial departures are viewed as unfair and. For example.” An analysis like that above could be undertaken for many decisions in which people care not only about material self-interest but also about their reputations and their self-conception—for example. 62. 14 J. 50:1471 where one party has violated a perceived “norm of fairness. Fairness as a Constraint on Profit Seeking: Entitlements in the Market.1496 STANFORD LAW REVIEW [Vol. An Attempt to Incorporate Fairness into an Economic Model of Tort Law. The relevant “fairness” notions there may be somewhat more “ad hoc.. see Henrik Lando. and we will stress this factor throughout. or through choosing friends. If parties are bargaining over the division of money and both have reason to view one side as more entitled than the other. 63. 61.

in SMOKING POLICY: LAW. AND CULTURE 69 (Robert L. the parties are likely to bargain to a different outcome if that outcome is preferable to what the court did and the transaction costs and wealth effects are small.1 (summarizing studies). since this would increase the surplus to be shared between them. Skolnick.. Willingness to Accept: Legal and Economic Implications. Bargaining Around Court Orders 1. and thus an instance of bounded rationality).65 This conclusion is suggested by the mugs experiments described in Part I. the parties should bargain for a lower damage level. 99 (1993). Rabin & Stephen D. Spitzer. Mug owners had become mug owners just minutes before the markets were run. See. which says that the assignment of a legal entitlement will not influence the ultimate allocation of that entitlement when transaction costs and wealth effects are zero. See Robert A. the assignment of a legal entitlement may well affect the outcome of bargaining.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1497 in behavior that have followed largely unenforced bans on smoking in public places—the phenomenon of “compliance without enforcement. Influenced by behavioral economics. 1993). Elizabeth Hoffman & Matthew L. (Thus. Behavioral analysis. Coasian prediction. many legal commentators have observed that in light of the endowment effect described in Part I (an aspect of prospect theory. L. Compare that with a homeowner who has been endowed with the right to have her homestead protected from noxious fumes being emitted nearby. A straightforward application of this idea is that when a court enters a judgment.66 The mugs results were obtained in circumstances that were the most favorable to the predictions of the conventional theory. See Kahneman et al. if the court enters a prohibitively high damage award but the activity in question is efficient. Sugarman eds. . 71 WASH. 66. at 1327 tbl. Transaction costs were zero and the sort of emotional attachments that can grow over time in the real world were absent. are irrelevant to the ultimate allocation of the entitlement in these circumstances. 65. Willingness to Pay vs. Kagan & Jerome H. 64. even when transaction costs (as conventionally defined) and wealth effects are zero. and how it is protected (by a property rule or a liability rule). 59.) To whom an entitlement is allocated after litigation. U. whether in the form of an injunction or a damage award.. Banning Smoking: Compliance Without Enforcement.. 2.g. for instance.Q. an important aspect of law and economics is the Coase theorem. As noted above.”64 B. e. POLITICS. supra note 26. as well as by a substantial body of other evidence on the endowment effect.

Even if communication is possible. 7 J. transaction costs would have been assumed to be zero as long as the two sides could easily negotiate. For all of these reasons. Bounded self-interest. deals are unlikely to occur. If “transaction costs” are defined in this broader way. and litigants are often not on speaking terms by the end of a protracted trial. 159-61 (1994). This observation illustrates an important general point. DECISION MAKING 157.1498 STANFORD LAW REVIEW [Vol. it can often be incorporated into economic analyses using standard concepts such as transaction costs. Once the behavioral analysis is understood. Source Dependence in the Valuation of Objects. This should not be taken to imply. First. Such a person may also believe strongly that this outcome is fair. however. and which thus produce court orders. Note that another way of phrasing this conclusion is that the concept of transaction costs is broader than conventional analysis assumes. 50:1471 Although the endowment effect suggests generally that the assignment of a legal entitlement may affect the outcome of bargaining. it is difficult to bargain without communication. the cost of assembling all of the relevant parties). such an effect is especially likely when the entitlement is in the form of a court order obtained after legal proceedings between opposing parties (our focus here). But that does not mean they are unimportant objects of study for purposes of positive 67. . and specifically the acrimony notions developed above. Experimental evidence suggests that there is an especially strong endowment effect when a party believes that he has earned the entitlement or that he particularly deserves it. so that those which do not. bargains are unlikely to be struck when both sides take pleasure in making the other side worse off. Even if there are financial gains from making a deal. See George Loewenstein & Samuel Issacharoff. that the behavioral analysis is superfluous. Under the usual account.67 Of course someone who has received a court judgment in his favor will believe that he has earned it. may be atypical in some respects. provide an additional reason we might expect less bargaining in real world settings than in law and economics texts. The costs of a transaction include not only the conventionally recognized ones (for example. behavioral research suggests that injunctions and damage awards may stick even with low transaction costs (as conventionally defined). hence. based on the self-serving bias discussed in the following section. It is of course true that most cases settle. for the reasons given above. the process of going through litigation may strengthen the endowment effect. they will very often be substantial in the case of bargaining around court orders. BEHAV. in such circumstances it can be difficult to reach agreements on settlements even if they would substantially improve the lot of both parties. then. This is so for several reasons. but also costs such as the discomfort or displeasure of dealing with an adversary.

REV. different outcome—favoring the other side—would also have been efficient). See A. is whether spite ought to count in the efficiency calculus. Morality and the Theory of Rational Behaviour. there is also a tricky normative issue: When people fail to reach bargains that would be reached in the absence of endowment effects and spiteful behavior. Mitchell Polinsky & Steven Shavell. 46 STAN. There is a large body of literature on this topic. Some of the most prominent utilitarian philosophers believe that it should not. Hay & Kathryn E. For a discussion of various approaches to this question in the context of endowment effects. 69. Mitchell Polinsky and Steven Shavell have acknowledged this view in their analysis of punitive damages as a response to the socially illicit gains obtained by certain defendants. behavioral analysis is concerned with the fact (and the consequences of the fact) that some cases proceed to trial.) The behavioral theory predicts that even in such cases. across the board. 675-97 (1994). in UTILITARIANISM AND BEYOND 39. See John C. there will often be no recontracting. it should be possible to test these differing predictions.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1499 analysis. if the parties do not contract around a court-ordered outcome for these reasons. 663. With conventional law and economics. In these circumstances. Litigation and Settlement. is there any problem from the standpoint of efficiency?69 On one view. 70. data gathered by Ward Farnsworth suggest that there is much less post-trial bargaining than the eco- 68. An underlying question. What happens once a court judgment has been entered? How often do the parties bargain to a different outcome? Consider the set of cases where the court has assigned an entitlement to the party who values it less. 908-10 (1998).. 55-56 (Amartya Sen & Bernard Williams eds. Even without this detailed type of information. L. Punitive Damages: An Economic Analysis.68 Although our focus in this section is on positive analysis. 869. Spier. Note. These theories can therefore be tested with empirical evidence. REV. Policymaking and the Offer/Asking Price Gap: Toward a Theory of Efficient Entitlement Allocation. L.70 3. Evidence. (The possibility of asymmetric information is discussed below in connection with the existing empirical findings. Harsanyi. Conventional economic theory and behavioral analysis thus generate distinct predictions about what happens after trials. then the outcome must be efficient (even if another. Conventional law and economics attributes failures to settle primarily to informational differences among parties. 111 HARV. uniquely efficient. the standard theory would predict contracting around the court order whenever transaction costs (as conventionally defined) and wealth effects are small. A. 1982). the answer is no. see Russell Korobkin. Since it is unlikely that court orders are. . in THE NEW PALGRAVE DICTIONARY OF ECONOMICS AND THE LAW (forthcoming 1998). which is summarized in Bruce L. however.

It is frequently remarked that law and economics is primarily theoretical or analytic. thus acrimony combines with the endowment effect to produce an absence of negotiation. for all. (This last point also means that the no-bargaining result cannot be explained by supposing that the court orders entered were uniquely efficient. 713. See. We think that before victory can be declared for either conventional or behavioral law and economics. the fit of the theory with the available evidence must be assessed. Once people have received a court judgment. and even when an objective third party might think that there was considerable room for mutually advantageous deals. A good aspiration for both conventional and behavioral 71. Having invested a great deal of resources in pursuing the case all the way to court and through a trial. what sort of study might be most useful. it is not enough to build a model consistent with behavior observed in an experimental setting (such as behavior in the ultimatum game or the mugs experiments). . In not a single case of those Farnsworth studied did parties even attempt to contract around the court order.1500 STANFORD LAW REVIEW [Vol. These tendencies are reinforced (according to the lawyers in Farnsworth’s study) by the presence of acrimony between the parties. and they are unlikely to give that right up. Bargains are unlikely in the extreme. Conventional analysis might attribute failures to reach an ultimate agreement to asymmetric information. of the tea in China. For behavioral analysis. REV. 734 & n. Ward Farnsworth. 72. the model must be compared and tested against what we observe in the world. Their investment in the entitlement gives it a distinctive character.) The lawyers’ explanations for these results are behavioral in character. It is also interesting to note that the lawyers interviewed said that the parties would not have reached a contractual solution if the opposite result had been reached. they are unwilling to negotiate with the opposing party. on file with the Stanford Law Review). 109 HARV. even when transaction costs were low. the plaintiff and the defendant tend not even to think about them. Victory is often declared based on a dataless model. partly because of an unwillingness by victorious plaintiffs to confer advantages upon their opponents. L.72 but under such analysis it is difficult to explain the complete failure even to negotiate. Here. victors perceive themselves as having a special right to the legally endorsed status quo. e.. if more evidence would be helpful. Do Parties to Nuisance Lawsuits Bargain After Judgment? A Glimpse Inside the Cathedral (1998) (unpublished manuscript. or most. our emphasis is on whether empirical evidence exists to test the predictions of the conventional and behavioral economic accounts. and. as elsewhere in this article. especially to their opponent.g.66 (1996) (discussing economic models in which asymmetric information leads to failed negotiations). Property Rules Versus Liability Rules: An Economic Analysis. and rarely empirical. Louis Kaplow & Steven Shavell.71 Farnsworth interviewed attorneys from approximately twenty nuisance cases in which injunctive relief was sought and either granted or denied after full litigation before a judge. 50:1471 nomic model would predict.

These parties may tend to see things in the light most favorable to them. Of course. this account is difficult to test. By contrast. bargaining may be more likely in that setting because neither side has yet been endowed through a court judgment with a clear entitlement. This is a form of bounded rationality—specifically. what is the appropriate reference transaction)—and thus there will be the opportunity for manipulation by self-interested parties. . 73. child custody. C. equivalently. the existence of such protracted litigation is somewhat of a puzzle. Self-serving conceptions of fairness. fair-minded agents that populate behavioral economics. This form of bias can help to explain the frequency of failed negotiations. while people care about fairness. For often there will be room for disagreement about what is fair (or. This is a separate question. parties should settle more than they do. self-serving bias and conditions of acrimony (as well as the background force of the “ordinary” endowment effect) may still preclude successful bargaining. a judgment error. With a good sense of the expected value of suit. POLINSKY. at 109-11. which may interfere with settlement prospects. most cases settle before trial. It is quite common. Even among the well-mannered. On the other hand. The next section examines the effect of self-serving bias on successful pretrial bargaining (as well as other forms of bargaining) in more detail. It may be possible to explain some of the observed behavior in terms of asymmetric information and signaling.g. e. self-interest is very much alive and well.. the effects of self-serving bias in negotiations have been tested empirically. to see protracted litigation in circumstances in which it might be expected that the parties would be able to reach negotiated solutions (although it of course remains the case that most suits settle). and so it is also important to ask to what degree bargaining is likely to be successful prior to this point. as described below. supra note 6. in cases involving divorce. Failed Negotiations 1. The empirical data and future empirical research discussed in this section concern behavior after a court has entered a judgment.73 However. See. and even commercial disputes. people’s perceptions are distorted by self-serving bias. their assessments of fairness are distorted by their own self-interest. On the standard account.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1501 approaches is careful empirical work that provides reasonably definitive conclusions about predictive failures and successes.

J. at 11. 50:1471 2. instead. Id. if the two sides have different views about comparable districts.633. Linda Babcock. ECON. at 10.78 Thus self-serving biases can explain real-world bargaining impasses. . In those school districts where the average salary of the union’s list is $1000 greater than the board’s list. Do participants in a negotiation choose comparable communities in a rational manner? Babcock. The authors regressed the percentage of previous negotiations that ended in a strike against the difference between the two sides’ lists of comparable districts. bargaining impasses may well occur. Xianghong Wang & George Loewenstein. Evidence. Nonetheless. 77.77 By itself. and Loewenstein hypothesized that they may not. Wang.4% of the average teacher salary in a setting in which the last offers before teacher strikes were typically about one percent apart. The average salary listed by union presidents for comparable districts was $27. at 13. substantial differences between the two sides emerged.1502 STANFORD LAW REVIEW [Vol. Respondents were asked to “list the districts they felt were comparable to their own. The regression showed that this difference had substantial explanatory power.922 for school board presidents. They designed a survey of union and school board presidents in all school districts in Pennsylvania. either to gain an advantage in negotiations or to curry public favor for one’s negotiating position. Id. 75. compared to an average of $26. 78. either as a measure of market conditions or as a characterization of what is fair.76 This difference was about 2.” and impasses may result from such judgments. this difference is highly suggestive. Id. 111 Q. Id. a strike is forty-nine percent more likely than where the average salaries of the two lists are the same.74 A common element of public sector labor negotiations is for both sides to invoke agreements in “comparable” communities. in order to elicit judgments about comparable districts for purposes of salary negotiations. The leading study in this area is one by Linda Babcock. 1 (1996). Choosing the Wrong Pond: Social Comparisons in Negotiations that Reflect a Self-Serving Bias. But do these self-serving views (reported to the authors of the study in response to a survey question) correlate with actual behavior? Yes. 76. 74.”75 Note that there is no strategic incentive here to misrepresent one’s view of which districts are comparable. the only audience for the responses in the study was the study’s authors. Xianghong Wang. and George Loewenstein on the consequences of self-serving bias for negotiation impasse in public school teacher contract negotiations in Pennsylvania. both sides may adopt self-serving judgments about which communities are “comparable.

researchers have conducted experimental studies on the role of self-serving bias in preventing negotiated agreements. For the participants have equal access to the information that defines what is a comparable player.79 The behavioral account seems to exhibit a higher “R2”—a better ability to predict the observed data—than the standard account. Subjects—college and law students—were randomly assigned to the role of plaintiff or defendant. supra note 80. 85 AM. who had reached a judgment between $0 and $100.527 higher than the defendants’. 81.000. 22 J.80 The studies involved a tort case based on real litigation in Texas. Thus behavioral economics appears more likely than the conventional model to predict and account for those negotiations that fail and end up in the hands of an arbitrator. George Loewenstein. at 151. in this role they were asked to negotiate a settlement. A fertile ground for future study of self-serving bias and its relationship to bargaining impasse may be negotiations between baseball players’ agents and team management. The subjects acting as the plaintiffs guessed an average $14. LEGAL STUD.709 higher than those of the defendants.81 Nonsettlement was strongly connected 79. Before beginning to negotiate. Linda Babcock. Samuel Issacharoff & Colin Camerer. They received a short summary of the case and also twenty-seven pages of materials from the original case. . 135 (1993). Loewenstein et al. Self-Serving Assessments of Fairness and Pretrial Bargaining. Biased Judgments of Fairness in Bargaining. They were also asked to say what they considered a fair amount for the plaintiff to receive in a settlement. once again as a measure of market conditions and as a characterization of what is fair. 80. George Loewenstein. and experimental evidence from other studies that points against such an explanation for the results. subjects were asked to write down their guesses about what the judge awarded. ECON.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1503 As already noted. The authors found quite substantial self-serving biases in subjects’ assessments of the judge’s award. strategic behavior does not seem to provide a strong explanation for the empirical evidence on school-district negotiations. and the plaintiffs’ fair settlement values averaged $17. It is common practice in these negotiations for both sides to use the contracts of “comparable” players as reference points. at 17-18. There was no incentive in the study (as there would often be in negotiations with the opposing party) for parties to choose comparable districts in a strategic manner. For a fuller discussion than space here permits of the possibility of strategic behavior. 1337 (1995). Subjects were told that the same case materials had been given to a judge in Texas. Exploration of the impact of this behavioral factor on the success or failure of these negotiations seems far more promising than examining the role of informational asymmetry in this setting. see id. Participants’ selection of which players are comparable may well be colored by self-serving bias.. In addition to the existing data on school district strikes. Colin Camerer & Linda Babcock. Samuel Issacharoff. REV.

979 (1994). as intermediators. Psychology. thirtytwo percent of lawyers report that they never request court-ordered compensation in excess of normal hourly rates. 72 WASH. are relatively less subject to various cognitive biases. U. 83. In the short time that it took to read all the materials. REV. George Loewenstein & Samuel Issacharoff. but the school district study suggests the importance of the bias in such settings. Id.1504 STANFORD LAW REVIEW [Vol. See Russell Korobkin & Chris Guthrie. and which might actually work. 86. 913 (1997). role-playing nature of this study in some ways strengthens the interpretation of the result. SOC. See Linda Babcock. INQUIRY. the fact that roles were only hypothetical. L. it suggests that part of the appropriate role of lawyers may be to counter their clients’ predictable inclination to overstate the fairness of their own cause. serious ethical issues may arise about the lawyer’s obligations. Are real lawyers immune from self-serving biases? There is some evidence that lawyers.3. 3. 84. the fairness of fees. Economics. 50:1471 to the discrepancy in predictions about the judge’s likely award. at 988 tbl. but judges report that only eleven percent of lawyers never make such requests. there is suggestive evidence that self-serving bias does affect lawyers and judges as well as other actors. 77 (1997).84 Thus. L.85 This evidence does not show that lawyers do not reduce self-serving bias in actual litigation. 76 TEX. means that we cannot be sure from these studies alone that parties would display self-serving bias in real-world settings.86 82. for example. This may be difficult since clients are the ultimate decisionmakers and lawyers may have an economic interest in not settling. in ways that can help promote settlement. Thus. A study of 205 bankruptcy lawyers and 150 bankruptcy judges found self-serving biases in responses to a wide range of questions involving how long it takes judges to rule on fee applications. Of course. and the financial stakes small. subjects adopted the point of view of their roles and the bias that comes with it. To the extent that it is possible for clients to be “debiased” by their lawyers. . and Settlement: A New Look at the Role of the Lawyer. 22 J. 85.83 However. Id. The role of lawyers. and lawyers’ fee awards in general. Theodore Eisenberg. To the extent that the bias is reduced through lawyers’ involvement. L. behavioral research provides considerable guidance on which debiasing techniques are least likely to be successful. but it casts doubt on the proposition that this bias is eliminated by the involvement of professionals. Differing Perceptions of Attorney Fees in Bankruptcy Cases.Q. Debiasing Litigation Impasse.82 Note that the hypothetical.

69 CORNELL L. 879. and causing the number of profitable trades to fall. Thus. in the example just given. 517. 890 (1975). a mandate should not be necessary. Some Simple Economics of Mandated Benefits. CHI. will make employers and employees. then the cost must exceed $100. 89. Richard Craswell. Charles J. for example. Rabin. 388-90 (1991). and the level of employment will fall. The conventional argument against mandatory terms such as those just mentioned has two steps. 954-55 (1984).88 we build upon Craswell in emphasizing the employment setting and in drawing upon a recent empirical study of the effects of mandatory contract terms. but. casts doubt on the conventional law and economics claim.1. May 1989. The Revolution in Residential Landlord-Tenant Law: Causes and Consequences. worse off. 88. REV. The second step in the conventional argument is that imposing a mandatory term in these circumstances will operate as a tax on the parties. if a particular employment benefit is worth $100 per year to employees and costs the employer only $90 to provide. then the employer will reduce the wage rate by somewhere between $100 (the value of the benefit to employees) and $110 (the cost of the benefit). Epstein. or landlords and tenants. Meyers.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1505 D. REV. 27 STAN. rules granting employees a particular level of workplace safety. Passing on the Costs of Legal Rules: Efficiency and Distribution in Buyer-Seller Relationships. One of the most frequent claims in the economic analysis of law is that the imposition of mandatory terms on parties to a contract will make both parties worse off. 180-81 & fig. See Lawrence H. . REV. in particular the endowment effect. Edward H. The Covenant of Habitability and the American Law Institute. L. L. 43 STAN. 79 AM. ECON. In Defense of the Contract at Will. First. if the cost of the benefit valued at $100 is $110. the price to rise) by somewhere between the benefit and the cost of the term. at 363. we suggest that bounded rationality. supra note 6. 361. Summers. Papers & Proceedings. L. Mandatory Contract Terms 1. Richard A. at least for the worker group 87. This analysis assumes an upwardsloping (not vertical) labor supply curve. 51 U. REV.. 558 (1984). REV. but if we do not observe the parties agreeing to the benefit on their own. or tenants the right to a habitable apartment. in the case of a habitable apartment. Our analysis here parallels that offered by Richard Craswell several years ago in the context of mandatory product warranties. since the parties did not bargain for the term in question when left to their own devices. Wage and price effects.89 Thus. For example. See POSNER. at 177. 515-17. it will operate as an effective tax on their transaction. the cost of the term must exceed its benefit (otherwise they would have agreed to it on their own). causing the wage to fall (or. 947.87 In this section.

Behavioral analysis. at 623. e. Departures from the assumptions of expected utility maximization by unboundedly rational agents suggest a different account of the effects of imposing mandatory contract terms. As noted above. 93.92 The study also found that the hours of employment of these workers were either unchanged or slightly higher with the mandate and that their probability of being employed was either unchanged or slightly lower. this assumption is clearly reasonable. Id. 630-31. 637. with little effect on net labor input. while the others yielded statistically significant results along the lines described in the text. Gruber performs a number of different regressions. they will not buy one for that price. one set did not yield statistically significant results. which predicts a fall in wages less than the cost of the benefit. 84 AM. “[t]he findings consistently suggest shifting of the costs of the mandates on the order of 100 percent.91 Imposition of the mandatory healthinsurance term—which represented a substantial departure from the usual contractual arrangements prior to the mandate—caused the wages of affected workers (most prominently.93 In sum. SAMUELSON & WILLIAM D. one that is consistent with the empirical findings just described. at 623.”94 These findings are not easy to reconcile with the conventional account. 636. REV. 1989).g. at 623. 91. then some substantial fraction of employers should have offered the benefit even prior to the mandate. married women of childbearing age) to fall by at least the cost of the mandated coverage according to most of the author’s estimates. 94. id.) 2. NORDHAUS. PAUL A. ECONOMICS 681 tbl. Thus. 633. . but if not given a mug. values indicating much more than full shifting of the cost. See. of course. Id. ECON. at 638. 92. (If the wage were going to adjust by the full cost of the benefit.28-2 (13th ed. The confidence intervals for the majority of these results also include values indicating less than full shifting of the cost—but also. Do the data bear out these predictions? The leading study in this area is by Jonathan Gruber. Jonathan Gruber.90 The conventional account thus offers sharp predictions about the effects of imposing mandatory contract terms. 50:1471 discussed below in connection with the existing empirical evidence (female employees).1506 STANFORD LAW REVIEW [Vol. Gruber examines the effects of imposing mandatory coverage of childbirth expenses in employer-provided insurance policies. 633. the fact that an employee (say) chooses not to purchase a particular workplace benefit if he is not granted an entitlement to it does not 90. they will not sell it for three dollars. if given a mug. 622 (1994). Id.. the endowment effect implies that people are often less willing to sell entitlements that are given to them than to buy entitlements that they do not already possess. The Incidence of Mandated Maternity Benefits.

supra note 88. then the wages of the affected worker will fall by as much as or more than the cost of the benefit. This is precisely what the Gruber study of mandated childbirth coverage finds. See. The second qualification is that the endowment effect may not operate in contexts in which the beneficiaries of a mandatory term must give up a preexisting level of income. imagine a labor supply curve prior to the imposition of the mandate. Richard Craswell offers an analogous analysis in the context of mandatory product warranties for consumers.. and the quantity of the good demanded may rise. In addition to Craswell’s discussion of mandatory terms. given the endowment effect. since they may be highly averse to such a loss.95 Three caveats are important here. at 388-90. it is also possible to have less than complete adjustment of the wage or price in the presence of the endowment effect. at 277-79 (arguing that changes in welfare must be evaluated in terms of an initial reference point and that “losses loom larger than gains”). the mandatory term may cause the price paid by consumers to adjust by more than the cost of the term. supra note 91. at 626 n. the endowment effect has been extensively discussed in the legal literature in connection with waivable contract terms and the Coase theorem. It is also possible that conventional economic analysis. Future empirical work could attempt to address the adverse selection possibility by examining the effects of mandatory contract terms in a setting in which (in contrast to the health insurance context) adverse selection is unlikely to be a significant force. In supplyand-demand terms. while the endowment effect is consistent with complete or more than complete adjustment of the wage or price. The corollary of this observation is that imposing a mandatory term may have different effects than the standard analysis predicts. If this occurs.g. and this move may more than compensate for the backward shift in the employer’s labor demand curve as a result of the mandate. As noted above. Hypothetical Bargains: The Normative Structure of Contract Interpretation. As Craswell describes. REV. 1867-68 (1991) (discussing waivable terms). . 97. e. reflecting willingness to work at different wage levels given provision of the benefit. 96. at 678-95 (concerning the Coase theorem). See Gruber. David Charny. L.97 95. See Craswell. supra note 1. by incorporating a market failure such as adverse selection (a possibility generally ignored by the above-mentioned critics of mandatory contract terms). supra note 12.9. 89 MICH. See Kahneman & Tversky. the consequence of the endowment effect may be that this curve is shifted to the right once the mandate is imposed. can explain the empirical findings discussed above.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1507 imply that he would want to sell the entitlement (if he could) once it has been granted. First. it may be just that they would be even less willing to supply labor in the absence of the benefit. 1815. Perhaps workers are not any more willing to supply labor in exchange for a given wage plus the benefit in question once they have an entitlement to the benefit. Kelman.96 Our point is just the modest one that the behavioral account can predict an instance of observed behavior that is inconsistent with the standard law and economics account of mandatory terms.

ECON. concerned with the effects of imposing a mandatory contract term. 50:1471 This qualification applies only to situations in which there is a financial loss relative to some preexisting expectation. from a normative perspective. Second. at 569. The final qualification here is that our analysis in this section is purely positive.99 The positive theory of law reflected in the conventional account predicts that the legal rules we observe will be rules that either maximize social wealth (if they are judge-made rules) or redistribute wealth to interest groups able to influence the legislative process. many laws that benefit farmers and concentrated industries. 99. but the situation without such terms is also efficient. Law and economics scholars who reject this account of the content of law have not offered any alternative account to explain and predict the rules we observe. Stigler.1508 STANFORD LAW REVIEW [Vol. & MGMT. 2 BELL J. The Theory of Economic Regulation. thus it would not apply to. for example. Unlike several of the scenarios discussed in Part V below. See POSNER. for the same reasons given by the standard account. what we wish to suggest is that the conventional view cannot be accepted a priori and that there is reason to think that behavioral law and economics points in helpful directions.98 Such laws can be thought of as solutions to optimal contracting problems with all of the affected parties at the table. 3 (1971). in the sense that they would not be undone (if they could be) once imposed. a consumer’s purchase of a durable good at a higher price due to the inclusion of a warranty. Our emphasis. for example. here there does not seem to be a clear basis for such a decision. THE CONTENT OF LAW One of the goals of law and economics is to explain the content of law— what the law allows and what it prohibits. supra note 6. and there is no obvious means by which the two situations can be compared. laws may be efficient solutions to the problems of organizing society. See George J. Instead. they may be efficient. . in which we think there is often a relatively strong argument for choosing one normative benchmark over another (say because people are likely to underestimate certain objective probabilities based on some form of judgment error). The primary point is that there is a substantial research agenda to test various hypotheses. laws may come about because of the rent-seeking activities of politically powerful actors. III. is the positive question of the effects of imposing mandatory contract terms. First. 98. then. The notion that laws emerge from considerations of efficiency and conventional rent seeking would probably strike most citizens as odd. SCI. The endowment effect does not necessarily imply that. The traditional approach provides two tools for this analysis. have been explained along these lines. mandatory terms are desirable.

We also do not claim that fairness concerns and bounded rationality explain every aspect of the content of law—just that they provide a useful supplement to existing explanations.” Certainly many criminal statutes would be explained without reference to either of the above factors. 1 BUFF. a prime example discussed below is the “availability entrepreneur. Our point is not the general (and rather obvious) one that fairness concerns and bounded rationality may shape the content of law. including views influenced by bounded self-interest and bounded rationality. self-interested legislators will respond. aspects of bounded rationality. 23 (1997) (seeking to explain criminal law based on the availability heuristic and other aspects of bounded rationality). and insofar as statutory rather than judge-made law is concerned) that legislators are maximizers interested in their own reelection. Legislators interested in their own reelection will be responsive to the preferences and judgments of their constituents and those of powerful interest groups. Judicial Choice and Disparities Between Measures of Economic Values. those that prohibit mutually beneficial exchanges without obvious externalities) and seem to benefit groups that do not have much lobbying power (such as the poor or middle class). What’s Law Got To Do With It?. that the purpose of the law is to codify “right” and “wrong. if a mobilized group holds such views.100 The mechanisms underlying our behavioral economic account of the content of law are simple and conventional. As we will try to show. L. Mobilized groups may also attempt to manage and exploit the public’s views. With the existing analysis. We argue that the explanation for the “anomalous” laws is typically a quite simple one: Most people think the result is fair.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1509 we suspect that most members of society—which is to say most of the people who are entitled to elect legislators—hold the view. many laws on the books appear to be difficult to justify on efficiency grounds (for example. and should be banned or regulated. CRIM. to bolster their own efforts. 30 OSGOODE HALL L. . If constituents believe that a certain practice is unfair or dangerous. as posited by the standard account. we seek to show specifically how behavioral analysis has real predictive and explanatory power. legislators’ response will be affected. undoubtedly naively. even if they do not share these views. and Sara Sun Beale. We also suggest that some laws we observe reflect neither efficiency nor conventional rent seeking but. we assume (for present purposes. instead.” who seeks to publicize an event in order to make 100. REV. in much the same way as if the group sought legislation to serve a narrowly defined financial self-interest.J. 737 (1992) (seeking to explain various legal doctrines based on the endowment effect). In this section we argue that law and economics explanations of the content of law need to be modified by incorporating the ideas of bounded self-interest (in the form of fairness norms) and bounded rationality developed above. Likewise. Our analysis in this part is similar in spirit to that offered by earlier work such as David Cohen & Jack Knetsch.

GA. COMP. § . is prohibited by many states in consumer lending transactions. GEN. STAT. § 750. § 518. STAT. 103. which impose constraints on gain101. MISS. STAT. MICH. CONN. § 4:1 (West 1997 & Supp. CODE ANN. is prohibited by roughly half of all states. MINN. § 578. but we do not discuss that point here because for the examples we consider. LAWS ch.. “Fairness entrepreneurs” may play a role. ticket scalping. mobilizing public judgments to serve their (selfish or nonselfish) interests. KY. CONSUMER CREDIT CODE § 2. CODE ANN. § 817. N. BUS.101 Price gouging. & COM. 50:1471 it more “available” to the general public. CONN.103 What accounts for these laws. MO.4 (1997). ANN. which play an occasional role.160 (West 1998).1510 STANFORD LAW REVIEW [Vol.Y. CODE § 8-31-3 (1997). N.201 (1974 Act). We do not mean to defend the laws that we describe. CODE ANN. CAL. LA. CODE ANN. A pervasive feature of law is that mutually desired trades are blocked. REV. MD. ANN. A. PENAL CODE § 396 (West 1998). STAT. § 97-23-97 (1994). or the charging of “grossly excessive” or “unconscionable” prices. ANN. REV. and ticket scalping. ANN. § 501. Bans on economic transactions. including New York (with its heavy theater population).M. GEN.36 (West 1998). ANN. § 4-318 (1992). Fairness norms interact with other forces to produce some of the seemingly anomalous laws we observe. STAT. A puzzle. ANN. STAT. § 5-63-201 (Michie 1997). 1997 ARK.465 (West 1991). REV. ANN. or charging an interest rate above a certain level.102 Finally. FLA. § 53-289 (1997). STAT. § 1746(25) (1998). 102. See UNIF. 140 §§ 185A. or the resale of tickets at prices well above face prices (in excess of a modest margin to cover ticket brokers’ costs). Usury. discussed below—are bans on conventional “economic” transactions. price gouging. § 29:732 (West 1988). LA. ACTS 376. LAWS ANN. such as usurious lending. See ARK. GA. TEX. we suggest more modestly that people’s commitment to fairness is part of the causal mechanism that establishes those laws. STAT. BUS. 185D (West 1994). ANN. STAT.395 (West 1995). § 609. public and interest-group perceptions seem to provide a good (and the most parsimonious) account of the laws we observe. and thus to increase the public’s demand for regulation. MASS. 1998). § 10-1-310 (1997). Perhaps most puzzling amidst this landscape—which includes bans on baby selling and vote trading. We suspect that a full account of the content of law would have to incorporate legislators’ independent judgments about fairness or risk.805 (West 1987). GEN. Bans on Market Transactions This section discusses the demand for the law insofar as that demand is affected by people’s bounded self-interest and in particular by their taste for fairness as they understand it. § 10-1-393. 1. STAT. § 42-232 (1997). is prohibited during “states of emergency” (as after a flood or other natural disaster) in many states that have had recent experience with such events. BUS. CODE ANN. GEN. FLA. See ALA. LAW § 396-r (McKinney 1997-1998). REG. CODE ANN.070 (Banks-Baldwin 1997).

Posner.Y. For an argument that usury laws can be explained on conventional economic grounds. ANN. Contract Law in the Welfare State: A Defense of the Unconscionability Doctrine. STAT. 1998). R. 1110 (1991) (offering quality-certification argument). John Tierney. S.) The difficulty with this form of argument as applied here is that it cannot explain the application of ticket-scalping laws to perennially popular events whose quality is known from TV and whose attractiveness to the public would not decrease significantly even with some diminution in demand—a category that includes many professional sporting events.I. Usury Laws. GEN. N. 1985). a significant departure from the “reference transaction.A above. 212 (West 1995). 24 J. CONS.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1511 producing transactions for ordinary commodities such as television sets and theater tickets? Not surprisingly. One might argue that ticket-scalping laws are an exception to this last point. GEN. restaurateurs might wish to outlaw it.. 4 PA. N. Dec. the transaction in question is a significant departure from the usual terms of trade in the market for the good in question—that is. and Related Limitations on the Freedom to Contract. for example. (We assume here that self-interested legislators are responsive to citizens’ or other actors’ demand for the content of law. ECON. STAT. TIMES. 283 (1995).Y. By contrast. § 14-344 (1997). economists and economically oriented lawyers often view these laws as inefficient and anomalous. A Note on Restaurant Pricing and Other Examples of Social Influences on Price. and ticket scalping when such activities are prevalent are a straightforward prediction of the theory of perceived fairness developed in Part II. §§ 211. and if a secondary market in restaurant reservations were to develop with very high prices for tables. e.g. see Eric A. Tickets? Supply Meets Demand on Sidewalk. LEGAL STUD.C. § 16-17-710 (Law Co-op. 26. See. 99 J.106 there does not seem to be a general theory or set of theories that can explain all or even most of these laws on traditional grounds. .105 (Thus. See Gary S. LAWS § 5-22-26 (1995). 106. CODE ANN.C. 105. 1992. Our point here is actually a more general one: Although it may be possible to offer efficiency or conventional rent-seeking explanations for certain sorts of laws banning economic transactions.104 The laws also do not generally seem well explained in terms of conventional rent seeking by a politically powerful faction. AFF. on the ground that ticket sellers (who may be politically powerful) might lobby in favor of the laws because moderate prices are necessary to create demand. LAW § 25.” Behavioral analysis predicts that if trades are occurring frequently in a given jurisdiction at terms far from 30-46-1 (Michie 1997). the argument would be that restaurant owners do not raise prices when waits develop for tables. price gouging. 1998) (effective June 1. 1109. which in turn certifies quality and makes the product more desirable. at A1 (quoting New York University economist William J. Peter Diamond has pointed out to us that ticket-scalping laws may be desirable to sports team owners who wish to engage in certain types of dynamic pricing strategies over the course of the season. A behavioral account.13 (McKinney 1984 & Supp. Baumol criticizing laws against ticket scalping). 104. Becker. N.) In the case of each of these bans. POL. ARTS & CULT. laws banning usurious lending.

. Since lumber generally tends to sell for a particular price. A week before Christmas a single doll is discovered in a store room. supra note 60.. price gouging. Note that the prediction is not that all high prices (ones that make it difficult or impossible for some people to afford things they might want) will be banned. so large mark-ups over that amount are judged unfair. for example. Thus. 109.”110 A system in which. at 735. of course. then the lender’s behavior may be viewed as unfair. subjects asked whether a team should allocate its few remaining tickets to a key football game through an auction thought that this approach would be unfair. Kahneman et al. 108. . Consistent with this last suggestion. Kahneman et al. it represents a departure from the “reference transaction. pervasive fairness norms appear to shape attitudes (and hence possibly law) on usury. an economic analysis would judge the auction the most efficient method of assuring that the doll goes to the person who values it most. supra note 60. Tickets to sporting events or the theater often sell for around the face price of the ticket. Kahneman et al. (Of course.1512 STANFORD LAW REVIEW [Vol. since it does not appear to be prevalent.” under which the doll is sold at its usual price. there will be strong pressure for a law banning such trades. what we predict will be banned are transactions at terms far from the terms on which those transactions generally occur in the marketplace. which drives demand sky high. only fans able to pay $3000 could attend the Super Bowl would be a system 107. 110. at S287-88. there would be no need for a law banning such behavior. .” but “[t]he lay public does not share this indifference. 50:1471 those of the reference transaction. if money is loaned to individuals at a rate of interest significantly greater than the rate at which similarly-sized loans are made to other customers. allocation based on who waited in line longest was the preferred solution. waiting in line for tickets is precisely what happens with laws against ticket scalping. are thought unfair. sales at far higher prices in the wake of (say) a hurricane.109 Of course. ..108 Although the auction is efficient.) As in the doll example.107 Nearly three-quarters of the respondents judged this action to be either somewhat unfair or very unfair. “Conventional economic analyses assume as a matter of course that excess demand for a good creates an opportunity for suppliers to raise prices” and that “[t]he profit-seeking adjustments that clear the market are . The managers know that many customers would like to buy the doll. though. They announce over the store’s public address system that the doll will be sold by auction to the customer who offers to pay the most. Id. as natural as water finding its level—and as ethically neutral. and ticket scalping. Consider this example: A store has been sold out of the popular Cabbage Patch dolls for a month. at 735. supra note 47.

Usury seems to be broadly prohibited. behavioral analysis predicts that if trades are commonly occurring with terms far from those of the reference transaction. Private behavior. and ticket scalping laws may be concentrated in states with very popular theater or sporting events. someone either qualifies for a loan at the offered rate or 111. As a positive matter. Ticket-Scalping Laws Protect the Average Fan.and middle-income consumers would be relegated to watching events at home or buying overpriced seats in the nosebleed section”. and ticket scalping laws we observe. TIMES. 1995.Y. Our goal here is simply to suggest the likelihood. . such a system of “entertainment Darwinism” would be a “raw deal” for the average consumer. or that a loan to a riskier borrower is a product different in kind from a loan to a safer borrower). Many of those who think “usurious” lenders are “unfair” might not have thought through the implications of their views (for example. Letter to the Editor. and whether conventional interest-group theories provide an alternative account. from the perspective of behavioral law and economics. Consider first usury: It is a well-known puzzle of lending markets that lenders often refuse to loan money to risky borrowers even at above-market interest rates. that paying an outrageous price for a loan may be better than paying an infinite price. N. More in-depth empirical research would be required to determine if these patterns bear out. price gouging and ticket scalping.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1513 characterized by the sort of severe departure from the reference transaction that people view as intolerable. The same cannot be said of price gouging and ticket scalping. such as the legal restrictions on usury. if such views are widespread. not a prescriptive or normative one about the shape practices or rules should take. they may underlie certain patterns in the content of law. Our claim here is a positive one about the content of the law we observe. It is interesting to note that these transaction-banning laws often mimic. We do not claim to have offered a definitive explanation for the pattern of usury. then legal rules will often ban trades on such terms. As a letter-writer to the New York Times colorfully put it in responding to coverage of ticket-scalping laws: “With legalized scalping. at A26. rather than constrain. rather. in systematic and predictable ways. Still. lower. Russ Haven & Amy Chester. Price gouging appears to be prohibited primarily by states that have recently experienced (or whose neighbors have recently experienced) natural disasters. May 9. that observed laws reflect. each is prohibited only in certain states. the behavior of the firms they regulate.111 We emphasize that we need not (and do not) find these views of fairness necessarily rational or compelling. fairness considerations as well as efficiency and conventional forms of rent seeking. price gouging. so one is not faced with the question of why we observe bans in some states but not others.

Tierney. N.115 More generally. Haddock & Fred S.R.117 For example. but in fact firms routinely do this. 1992. 71 AM. 85 GEO. 258 (1996) (discussing the residential mortgage lending market). when Hurricane Andrew hit Florida and the demand for lumber and other building supplies skyrocketed. and despite the fact that no law banned price increases. e. Happel & Marianne M. Hylton & Vincent D. disaster for Broadway. See Stephen K.116 Likewise. Why Do Firms Contrive Shortages? The Economics of Intentional Mispricing. LEGIS. 23. Credit Rationing in Markets with Imperfect Information. D5. As the head of a major theater company explained.J. “there’s a strong public relations argument” against raising prices for tickets for very popular shows (and presumably sporting events as well)—despite excess demand for seats at the going prices—because the public already believes “that Broadway ticket prices are too high. 1566-68 (1995) (citing Joseph P.”119 Why would it be a “P.”118 “Even though we could sell tickets at $100. See Michael Klausner.R. 118.114 but they cannot easily explain the existence of laws against such behavior. despite the fact that the stock could have been sold at an enormous (short-term) profit. INQUIRY 562. 32 ECON. head of the Shubert Organization). economists have often remarked on the failure of firms to increase prices in response to temporary increases in demand. Home Depot. ECON. See Hylton & Rougeau. .1514 STANFORD LAW REVIEW [Vol. disaster” if the market would allow them to sell 112. Lessons from a Hurricane: It Pays Not to Gouge. supra note 112.112 This is true even when a modest increase in the interest rate would not violate usury laws. 8-9 (1989). N. 116. the Chicago Bulls sold some tickets to the general public at prices that were somewhat higher than regular season games but a fraction of the price the tickets commanded on the (legal in Illinois) ticket broker open market. Why Aren’t Tickets Costlier?.85. Sept.g. 16 J.Y. L. Dec. TIMES. at D1. L. during the 1997 NBA playoffs. supra note 104. 119.. 50:1471 does not qualify for a loan at all. Peter Passell. Econometric Evidence.Y. 1561. at 258 & n. REV. and the Community Reinvestment Act. Stiglitz & Andrew Weiss. 113.” another theater owner said. Assessing the Economic Rationale and Legal Remedies for Ticket Scalping. 114. See. 143 U. at D24 (quoting Rocco Landesman. REPORT TO THE CONGRESS ON COMMUNITY DEVELOPMENT LENDING BY DEPOSITORY INSTITUTIONS 34 (1993) (same). If Scalpers Can Get So Much. continued to sell these goods at its usual prices. 393 (1981)). Jennings. 117. PA. REV. 1. BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM. Lending Discrimination: Economic Theory. for fairness explanations of this behavior. 22. McChesney. 115. 237. TIMES. a major national chain. at D2 (quoting Gerald Schoenfeld. 1993. Keith N. 562-63 (1994) (surveying the economic literature). an interesting feature of ticket-scalping laws is that they will keep prices down only to the extent that firms choose to sell tickets at reasonable prices in the first place.113 (Adverse selection considerations may also explain this behavior.) Price gouging and ticket scalping are similar in terms of private actors’ behavior. Rougeau. See David D. president of Jujamcyn Theaters). Market Failure and Community Investment: A Market-Oriented Alternative to the Community Reinvestment Act. “we’d be cutting our own throats because it would be a P. See Steve Lohr. Thus.

supra note 115. Other bans. 123. See Radhika Rao. It is these actors who are regulated by the law. across a wide range of contexts. People may not buy and sell body parts. Senate Committee OKs Bill to Legalize Scalping of Tickets. In each of the contexts we examine. ELIE R. See Lohr.S. 1077. DAVID E. when sports teams sell playoff tickets to season ticket holders at below-market prices. REV. 1994. CANETTI. 124. 45 UCLA L. L. Mar. None of this is to say that firms never raise prices in an opportunistic fashion. it appears that firms typically support and even lobby for laws against ticket scalping.125 and baby 120. LEBOW & JEREMY B. at 36A. The more powerful mainstream firms will tend to support. 1997. have no reason to keep prices down. at D1.D.. Laws banning economic transactions are just a species of a broader form of regulation of transactions.226 (1998) (citing state statutes). 1117 n.120 Note that this is not a standard reputation story. See Steve Kukolla. 122. 970. Ticket Selling: One Big Unhappy Family. 121. Richard A. REV. . our point is just the modest one that fairness norms often seem to constrain firms’ behavior in much the same way that they shape laws against behavior violating those norms. ASKING ABOUT PRICES: A NEW APPROACH TO UNDERSTANDING PRICE STICKINESS 9-10. who are typically anonymous actors engaged in one-time transactions. Reconceiving Privacy: Relationships and Reproductive Technology.C. Noninstitutional lenders may be willing to lend at exorbitant rates. though. Why Restrain Alienation?. recent evidence of price stickiness shows that firms’ behavior seems to be affected greatly by their customers’ perceptions of unfair price increases. e. 20. Epstein. for instance. rules banning unfair transactions.121 Why then are the laws necessary? Some of the relevant actors will not be constrained by fairness norms in the absence of a law. commercial surrogacy is prohibited. June 20-26.123 They cannot sell their votes. suppliers selling lumber out of the back of pick-up trucks will often charge whatever the market will bear (as occurred after Hurricane Andrew). 125. INDIANAPOLIS BUS.122 ticket scalpers..g. at 2. Consistent with the foregoing analysis. Consistent with our analysis. ALAN BLINDER. 149-64 (1998).124 In some states. that their support would not be predicted by the standard account.) 2. § 274e (1991). (Note. or at least not oppose. ATLANTA CONST. See. J. RUDD.. it may be that the ticket holders paid a premium for the playoff tickets ex ante (through the purchase of season tickets).May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1515 their tickets at $100? We think this would be so because a $100 ticket price for a very popular show would have been viewed as unfair by many members of the public given that the usual price for a ticket was below this. 987 (1985). fairness considerations are the reason that raising prices harms the firm’s reputation. Many deals are blocked. See 42 U. 85 COLUM.

51-52 (1974) (dicta). We make a simple positive point here: Behavioral analysis suggests that pervasive judgments about fairness may account for many such bans on voluntary deals. However. B.. those questions have been well-ventilated. may affect law involves one of the enduring puzzles in First Amendment law: the special judicial hostility to “prior restraints” on 126. 20 (1991). 26 PAC.g. no court to our knowledge has suggested that Gilmer or any other recent case permits people to “sell” their substantive rights not to be subject to race and sex discrimination. e. Is Wrong with Baby Selling?. What. Prior Restraints on Speech Another instance in which fairness-related norms. baby selling) regardless of the existence of a law banning them. 135. In banning certain deals. legislators may be responding to community sentiments about what kinds of things are properly subject to market arrangements. and in addition bounded rationality. what sorts of transactions were generally not engaged in (despite their being technologically feasible—for example. Whether or not those judgments make sense. Gardner-Denver Co. 500 U. in which case the reference point obviously could not account for the existence of the ban. predicts that such transactions will be banned only if a ban is either efficient or favorable to a politically powerful interest group. How could this behavioral theory of law be tested? One idea is to determine. just as the norm or benchmark is the usual or face price of the ticket. If Anything.) Behavioral analysis predicts that such transactions will be legally censured.S. See Margaret Jane Radin. Doubtless reasonable distinctions can be drawn between bans in different areas. . 36.” Departures from that norm are viewed as unfair and are prohibited. as for example through written agreements.126 People may not contract around bans on race and sex discrimination. The specific issue presented in Alexander—the enforceability of agreements to arbitrate discrimination claims— has been considered in more recent cases.127 Blocked trades can be found in every American jurisdiction. 415 U. the norm or benchmark here is “no market exchange. Bans of this variety raise serious normative questions. See Alexander v. they seem to be widespread. or an equal division of the amount to be divided in the ultimatum game. The existing law and economics analysis.. Gilmer v.J. See. 135 (1995). 50:1471 selling is banned in all states. (The importance of looking to a pre-law benchmark is that the existence of a legal ban could itself produce a no-market-exchange reference point. based on historical evidence.S.. and they help to explain the persistence of legislation that is often difficult to explain by reference to an efficiency or rent-seeking account. Interstate/Johnson Lane Corp. by contrast. These transactions could be said to have a no-transaction benchmark. sometimes externalities are readily apparent. 127.1516 STANFORD LAW REVIEW [Vol. The reference transaction in these areas is generally “no transaction”. L.

individuals will typically be reluctant to forego rights granted by such remedies.129 Those defenses urge that the real purpose of the prior restraint doctrine is to ensure that no regulation is imposed without a reliable judgment that the First Amendment does not protect the speech at risk. See Martin H. the injunction might be thought to create the prospect of a greater total punishment for the speech. this account matches the most sophisticated defenses of the special barrier to prior restraints.128 A court may well refuse to issue an injunction against speech even if it would allow subsequent punishment of that same speech. TUSHNET. and the latter are nonetheless more troublesome than the former. 70 VA. CASS R. A criminal statute. many criminal statutes impose greater punishments than many injunctions. 128. L.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1517 speech. SUNSTEIN & MARK V. is likely to produce a different response on the part of the prosecutor. REV. STONE. most notably injunctions. GEOFFREY R. e. Why is a criminal statute any less problematic than an injunction whose violation produces criminal penalties? Conventional economic analysis provides no satisfying answer to this question. CONSTITUTIONAL LAW 1183-96 (3d ed. The Proper Role of the Prior Restraint Doctrine in First Amendment Theory. 55 (1984). LOUIS M. This is apt to be as true for prosecutors as for everyone else. 53. Can behavioral analysis explain the law’s special treatment of prior restraints? As noted in Part I. The puzzle is that a prior restraint involves subsequent punishment too. The doctrine is difficult to explain on conventional economic principles but is a natural inference from behavioral ones. True. A prosecutor who has sought an injunction may be particularly insistent on ensuring that punishment occurs. In any case. Reasonable defendants know the difference. what an injunction means is that a violator will be subject to (subsequent) sanctions.B above. SEIDMAN. . See. but no one has suggested that the First Amendment imposes limits on the severity of punishment for speech that the government is entitled to criminalize. As it happens. 1996). due to the perceived unfairness of that outcome and the type of attachment created by the endowment effect. Hence it is especially important for a court to ensure that any injunction imposed on speech is not issued in advance of an accurate judgment that the speech involved is unprotected by the First Amendment. standing by itself and unaccompanied by an injunction. court-ordered remedies are likely to create special forms of attachment for their beneficiaries.g. 129. Redish..

supra note 3. 131. it can lead to systematic errors in probability assessment. In the context of environmental legislation. TIMES. Extensional Versus Intuitive Reasoning: The Conjunction Fallacy in Probability Judgment. In this section we offer an account of the Superfund statute. 50:1471 C. 1994. N.000-word section of a novel end in “ing” give much larger estimates than individuals asked how many words in such a section have “n” as the second-to-last letter. on how easily such instances come to mind. perhaps the most well-known and popular environmental statute. See. at A1. it encourages the well-known “pollutant of the month” syndrome. Amos Tversky & Daniel Kahneman. 21 OHIO N. .C. Many illustrations come to mind. 15 U. But judgment errors by boundedly rational individuals also play a significant role here. L. REV. made inaccurate by the availability heuristic. Anecdote-Driven Environmental Legislation (With Particular Reference to Superfund) 1. A20. 590 (1995) (referring to an ABC news special on how media reports “heightened anxiety over .133 The same phenomenon may occur in other areas of regulatory law. See Asbestos Hazard Emergency Act of 1986. . 133.131 When beliefs and preferences are produced by a set of probability judgments.132 or the strict regulation of asbestos in schools after a large amount of media attention. REV. In particular. Margo L.. on this ground. Estimating the likelihood of uncertain events. 295 (1983). See Sunstein. that is. Electromagnetic Fields and Cancer: A Legitimate Cause of Action or a Result of Media-Influenced Fear. 90 PSYCHOL. but the error is fully rational—in the sense of reflecting optimizing behavior—for people with limited information. at 1188. Stoffel. Thus far the discussion has focused on the role of bounded self-interest (specifically. 551. Their judgments about probabilities will often be affected by how “available” other instances of the harm in question are.g. May 11. fairness-related norms) and the endowment effect in predicting and explaining the content of law. 293.Y. where regulation is driven by recent and memorable instances of harm. Comment.U. Keith Schneider.1518 STANFORD LAW REVIEW [Vol. asbestos in schools”). consider the outcry over Agent Orange and Times Beach.130 Reliance on how “available” instances of the event in question are is a form of judgment error. Fetal Harm Is Cited As Primary Hazard In Dioxin Exposure. 132. despite the fact that objectively there are more words which satisfy the latter criterion than the former. people seek law in areas such as environmental protection on the basis of their judgments about the probabilities associated with certain harmful activities. e. . §§ 2641-56 (1994).S. Here is a familiar example of availability: Individuals asked how many seven-letter words in a 2. Still. an example here is the move to- 130. legislation will predictably become anecdote-driven.

135 Well-organized groups in the private sector very frequently use this strategy. particularly if the harm in question is highly salient. See Howard Kunreuther. Thus. ANAL. if a particular hazard has materialized recently. then regulation will be demanded. on file with the Stanford Law Review). “Availability entrepreneurs” will thus focus attention on a specific event in order to ensure that this event will be salient and available to many members of the public. Although self-serving behavior by such actors is an element of the conventional economic account. see Colin F. operating strategically to promote their selfish or nonselfish goals. and politicians. even an unlikely one. salience is heavily influenced by the way the event is packaged by the media.. 565. For a discussion of overestimation of the likelihood of lowfrequency events. the role of such factors as availability is not. 243-44 (1976). HARFST. for example. Apart from the nature of the event. 566 (1989). for instance. Sunstein. in DECISION MAKING: AN INTERDISCIPLINARY INQUIRY well as over-regulation.136 many health and environmental risks (such as the health threats from poor diet and exercise) may fit this description with some parts of the population. Availability Cascades and Risk Regulation (Apr. where many children are present. The behavioral account thus predicts a patchwork of environmental laws characterized by both overand under-regulation. Limited Knowledge and Insurance Protection. with the discovery of asbestos in schools. . as when. Camerer & Howard Kunreuther. And this is particularly true if the hazard has a high degree of salience—as. becomes available. 1982). Self-interested politicians may use similar strategies to enhance their reelection prospects.134 What determines how available a particular environmental hazard is? Two factors are particularly important: the observed frequency of the hazard and its salience. thus showing that they are fine behavioralists. 209 (Gerardo R.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1519 ward heavy regulation of school bus safety in the wake of media coverage of school bus accidents in which children were killed. Decision Processes for Low Probability Events: Policy Implications. The Economics of Protection Against Low Probability Events. 1998) (unpublished manuscript. People sometimes (although not always) underestimate the likelihood of lowprobability or low-salience events because these threats simply do not make it onto people’s “radar screens”. organized interest groups. 135. 24 PUB. POL’Y 227. The availability heuristic can lead to under. 26. See JERRY L. But when a particular threat. 134. 235-36. See Timur Kuran & Cass R. asbestos is discovered in schools. MASHAW & DAVID L. These actors are amateur behavioralists. this is what is added by behavioral analysis. & MGMT. Howard Kunreuther. POL. Interested actors in the private and public sectors can be expected to exploit the availability heuristic for their own purposes. 136. people are likely to attach a higher probability to its occurring in the future. Braunstein eds. with over-regulation when a particular risk has recently materialized. THE STRUGGLE FOR AUTO SAFETY 14146 (1990). 8 J. Ungson & Daniel N.

762 (1990) (same). But an examination of the history of the statute shows that this explanation is extremely weak.139 Experts contend that in terms of risks to human health. Americans have consistently ranked “abandoned toxic waste dumps” among the three most important environmental problems. We draw here from the more detailed discussion in Kuran & Sunstein. Instead the key actor. RATIONAL RISK POLICY 96 (1998) (discussing role of availability). but they fail to account for Superfund. Superfund was passed with substantial legislative and public support. the fact that the behavioral account predicts the enactment of Superfund.. Noll & James E. as described more fully below. Some Implications of Cognitive Psychology for Risk Regulation. there are at least a dozen problems that are more serious. supra note 135. and second. KIP VISCUSI. and the key mechanism was the availability heuristic. 139. 247. Interest groups played little part in initiating its enactment.137 We wish to add two features to the analysis: first. what is remarkable is how little opposition the statute provoked. 747. Availability provides a convincing explanation of Superfund’s existence and its endurance. Explanations of this kind have had some success. Superfund is no exception. Constitutional Moments. 48 STAN. in light of its crudely drafted character and uncertain empirical support. Superfund. many of them receive less in the way of public (and legislative) support. Some of these groups are sincerely concerned with environmental protection. The basic point that availability may affect the demand for environmental legislation is not new. 50:1471 2. REV. STEPHEN BREYER. 265-66 (1996) (same). a major piece of environmental legislation that is not readily explained on conventional grounds. 19 J. if indeed it qualifies as a serious problem at all. L. Its initial development occurred when officials within the 137. e. What is even more remarkable is that for the last seventeen years. . was the Environmental Protection Agency. Roger G. BREAKING THE VICIOUS CIRCLE: TOWARD EFFECTIVE RISK REGULATION 21 (1993). an understanding of the mechanisms through which the availability heuristic may operate to produce environmental legislation (and here we emphasize the notion of “availability entrepreneurs”). 138. See.1520 STANFORD LAW REVIEW [Vol. LEGAL STUD. Of course it is possible (as it always is) to generate post hoc accounts that show that some groups benefited from legislation. Congress. Cass R. even though experts believe that this is one of the least pressing environmental problems. and to suggest that such legislation was passed because some groups benefited from it. Sunstein. others have economic interests for which environmental issues operate as a smokescreen. these groups can use the law to redistribute resources in their preferred directions. See W.138 Conventional approaches point to the important role of interest groups in shaping environmental law. and the Cost-Benefit State.g. Krier.

There can be no doubt that the Love Canal publicity was pivotal to the law’s passage in 1980. though powerful private groups did not seek the legisla140. national news began to focus on what was soon seen as a “ticking time bomb” at Love Canal. And to this date. 1978. 1657 (1997) (finding that in the presence of divergent information about risks. people place inordinate weight on high risk assessments). The ultimate design of the statute surely owed a great deal to what relevant interest groups were willing to tolerate. A kind of cascade effect occurred. . We do not say that conventional interest-group considerations played no role in the specific shape the Superfund statute took. Time magazine made the topic a cover story. that hundreds of “Love Canals” could be found throughout the country. The publicity continued in 1979 and 1980. By the way. The behavioral account of Superfund is that the availability of “Love Canal” as a symbol for the problem of abandoned hazardous waste dumps greatly intensified public concern. J. the national news was saturated with stories of the risks to citizens near Love Canal. But it is doubtful that the EPA could have succeeded if not for the fact that in August of 1978. The EPA thus became an “availability entrepreneur. and hence in the period between August and October. Polls showed that eighty percent of Americans favored prompt federal action to identify and clean up potentially hazardous abandoned waste sites.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1521 EPA. Cf.” focusing attention on a specific event in order to ensure that this event would be highly available to many members of the public. 1978. very publicly. In that year. In the middle and late 1970s. Within two weeks. consisting of apparent leaks from the disposal of 21. studies of groundwater and cancer incidence appeared to show that the leaks had created serious health risks. W. 107 ECON. Alarmist Decisions with Divergent Risk Information. the prime proponent of the new legislation—the EPA—warned. During crucial periods in the legislative debate.000 tons of chemical waste into the Canal between 1943 and 1952. American presidents and serious presidential candidates of both parties invoke abandoned hazardous waste dumps as a leading environmental problem. to the point where a legislative response became nearly inevitable. Kip Viscusi. Congress responded quickly with the new statute. the crucial years for Superfund’s enactment. to the point where the New York Health Commissioner declared a public emergency on August 2. New York. began to draft new legislation in order to respond to the existence of abandoned hazardous waste sites. no matter what the actual facts might be.140 And there can be no doubt that proponents of Superfund self-consciously exploited the Love Canal incident. it remains unproven that Love Canal created significant health risks at any stage. concerned about an apparent gap in federal law and eager to consolidate their authority over issues of public health. President Carter declared an emergency in the area. and network documentaries followed suit.

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tion, they did influence its content and structure. But the enactment and continued popularity of Superfund are not predicted by the conventional account alone. The behavioral account, in contrast, suggests that the occurrence of an event such as Love Canal, particularly when played up and dramatized by the media and other actors, will produce a legislative response. Superfund is one example; regulatory responses to Agent Orange and asbestos in schools are others. Available instances of risk or threat seem to shape the content of law. IV. PRESCRIPTIONS In this part we shift our focus from the positive to the prescriptive. Instead of seeking to explain what the effects of law will be and why we have the laws we do, we now explore how the law can best be structured to achieve specified ends—deterring socially undesirable behavior through the tort system, encouraging measures that enhance human health, and so on. Our claim in each context we consider is that attention to behavioral insights can improve the law’s ability to move society toward desired outcomes. Our primary emphasis is on problems in processing information, problems that create difficulties both for juries during trials and for those responding to information required by government or coming from government itself. Thus bounded rationality, in the form of both judgment errors and behavior in accordance with prospect theory rather than expected utility theory, are the central emphases in this part. Section A deals with juries, while section B deals with government information campaigns and mandatory disclosure. Section C emphasizes our second bound on human behavior, bounded willpower, and discusses its relevance to prescriptions directed toward deterring crime. This part discusses only a small sample of the many areas in which sound prescriptive analysis may require us to consider possible bounds on jurors’ or other actors’ decisionmaking. Other authors have applied these insights to other topics in the economic analysis of law. Thus, for example, Daniel Kahneman and David Schkade, along with one of the present authors (Sunstein), have challenged the economic prescription for punitive damage awards recently offered by A. Mitchell Polinsky and Steven Shavell: that juries should be instructed to focus on the probability of nondetection of the tortfeasor’s activities in order to achieve optimal deterrence through punitive awards.141 From the behavioral point of view, this prescription fails to appreciate the cognitive and motivational limitations on jury decisionmaking. Because of the hindsight bias and overoptimism problems described below, juries will have difficulty making probability estimates, and in addition they
141. See Polinsky & Shavell, supra note 70, at 887-91.

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appear to come to the task of awarding punitive damages with strong retributive instincts.142 The goal of optimal deterrence may be best achieved through administrative agencies rather than juries.143 Another example of the application of behavioral economics to prescriptive analysis is Thomas Jackson’s discussion of discharge policy in bankruptcy law. Although standard economic ideas of risk allocation would often support nondischargeability of debts, Jackson draws on aspects of what we have termed bounded rationality and bounded willpower to support the “fresh start” policy of discharge and to sketch the specific contours it should take.144 Our goal in this part is to point to some additional topics in the economic analysis of law in which a more accurate understanding of decisionmaking can improve upon conventional law and economics prescriptions. A. Negligence Determinations and Other Determinations of Fact or Law 1. Background. Frequently juries are called upon to determine the probability of an event that ended up occurring; a prominent example is the negligence standard, which (in the formulation favored by the economic analysis of law) requires jurors to assess the costs and benefits of the defendant’s course of action from an ex ante perspective, and thus to determine the probability that harm would end up coming of that action. These determinations are made with the “benefit” of hindsight; jurors know at the time they make their decision that the event in question did in fact occur. Jurors’ determinations are thus likely to be afflicted by “hindsight bias”—the tendency of decisionmakers to attach an excessively high probability to an event simply because it ended up occurring.145 Hindsight bias has been observed in a large number of studies, including studies of “expert” actors such as physicians, who, when asked to assess the probabilities of alternative diagnoses, given a set of symptoms, offer significantly different estimates depending on what they are told the actual diagnosis turned out to be.146 Hindsight bias also appears to occur in the specific

142. Cass R. Sunstein, Daniel Kahneman & David Schkade, Assessing Punitive Damages (with Notes on Cognition and Valuation in Law), 107 YALE L.J. 2071, 2111-12 (1998). 143. Id. at 2122-25. 144. Thomas H. Jackson, The Fresh-Start Policy in Bankruptcy Law, 98 HARV. L. REV. 1393, 1394-95, 1399-1401 (1985). 145. See Baruch Fischhoff, Hindsight ≠ Foresight: The Effect of Outcome Knowledge on Judgment Under Uncertainty, 1 J. EXPERIMENTAL PSYCHOL. HUM. PERCEPTION & PERFORMANCE 288 (1975). 146. Hal R. Arkes, David Faust, Thomas J. Guilmette & Kathleen Hart, Eliminating the Hindsight Bias, 73 J. APPLIED PSYCHOL. 305, 306 tbl.1 (1988).

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context of negligence determinations.147 In the negligence studies, subjects in the role of jurors—armed with knowledge that harm had in fact occurred—were found to attach significantly higher probabilities to harm than subjects in the role of ex ante decisionmakers—those not informed of the occurrence of harm.148 This is a straightforward prediction of the many prior studies on hindsight bias.149 Although the negligence studies asked for individual rather than group probabilities (raising the question whether group interaction on an actual jury could dispel hindsight bias), other studies have found hindsight bias in group as well as individual settings.150 Hindsight bias will lead juries making negligence determinations to find defendants liable more frequently than if cost-benefit analysis were done correctly—that is, on an ex ante basis. Thus, plaintiffs will win cases they deserve to lose. This prediction is consistent with the frequently expressed (though difficult to verify) view that the tort system imposes too much liability.151 A threshold issue raised by the hindsight-bias account of negligence determinations is whether hindsight bias is simply a countervailing weight to a tendency on the part of defendants to underestimate the likelihood of being sanctioned. A common feature of human behavior is overoptimism: People tend to think that bad events are far less likely to happen to them than to others. Thus, most people think that their probability of a bad outcome is far less than others’ probability, although of course this cannot be true for more than half the population.152 If defendants exhibit such overoptimism, then they will be underdeterred by a correct application of the negligence stan147. See Kim A. Kamin & Jeffrey J. Rachlinski, Ex Post ≠ Ex Ante, 19 LAW & HUM. BEHAV. 89 (1995); Susan J. LaBine & Gary LaBine, Determinations of Negligence and the Hindsight Bias, 20 LAW & HUM. BEHAV. 501 (1996). 148. Kamin & Rachlinski, supra note 147, at 98; LaBine & LaBine, supra note 147, at 50910. 149. See, e.g., Arkes et al., supra note 146. 150. See Dagmar Stahlberg, Frank Eller, Anne Maass & Dieter Frey, We Knew It All Along: Hindsight Bias in Groups, 63 ORG. BEHAV. & HUM. DECISION PROCESSES 46 (1995); Ed Bukszar & Terry Connolly, Hindsight Bias and Strategic Choice: Some Problems in Learning from Experience, 31 ACAD. MGMT. J. 628 (1988). 151. See, e.g., JEFFREY O’CONNELL, ENDING INSULT TO INJURY: NO-FAULT INSURANCE FOR PRODUCTS AND SERVICES 42-43 (1975); John G. Fleming, Drug Injury Compensation Plans, 30 AM. J. COMP. L. 297, 311 (1982); Stephen D. Sugarman, Doing Away with Tort Law, 73 CAL. L. REV. 555, 581-82 (1985). 152. See Neil D. Weinstein, Unrealistic Optimism About Future Life Events, 39 J. PERSONALITY & SOC. PSYCHOL. 806 (1980); Neil D. Weinstein, Unrealistic Optimism About Susceptibility to Health Problems: Conclusions from a Community-Wide Sample, 10 J. BEHAV. MED. 481 (1987) [hereinafter Weinstein, Unrealistic Optimism]. For discussion of the distinction between being below the average person’s probability of a negative event and being below the average probability of that event (which could in fact be true for the majority of people), see Christine Jolls, Behavioral Economic Analysis of Redistributive Legal Rules, 51 VAND. L. REV. (forthcoming 1998).

May 1998]

dard; overestimation of the probability of harm based on hindsight bias might then be a desirable countervailing factor. We think that defendant overoptimism is likely to be a much smaller factor for firms than for individual defendants, since firms that make systematic errors in judgment will be at a competitive disadvantage. And for individuals, the role of overoptimism is likely to vary significantly with context. In a case in which the threat of being found liable is highly salient, individuals may tend to overestimate the likelihood of being sanctioned, for reasons discussed in connection with our account of Superfund above. Hindsight bias, in contrast, seems to be an across-the-board phenomenon; it has been observed in a wide range of contexts across many studies and is likely to be present whenever a jury makes a negligence determination. It is also possible that the occurrence of harm itself provides genuine information about the probability of harm; this fact has led some to consider the possibility of an “ex post negligence” standard, under which negligence is assessed based on the information available ex post, rather than ex ante.153 (However, if prospective defendants cannot easily ascertain (ex ante) the information that will be available ex post, then an ex post approach may be inefficient.154) But, even apart from situations in which the fact of harm provides new information about the probability of harm, hindsight bias suggests that decisionmakers will weigh the fact of harm heavily in assessing its probability.155 The findings on hindsight bias provide new empirical support for the old idea that such bias may distort negligence determinations. Despite the vast law and economics literature in the area of torts, no attention seems to have been paid to the potentially significant implications of hindsight bias for achieving optimal deterrence—the goal posited by that literature, and the goal on which we focus here. (Thus, we accept this goal for purposes of our prescriptive analysis; we do not necessarily endorse this goal from a normative perspective.) Law and economics scholars generally approve of the use of the negligence standard for achieving the goal of optimal deterrence; the negligence standard, if applied in an error-free fashion, leads to an efficient level of precaution (although other standards will as well; note that these other standards may be worse or better along other dimensions, such as encouraging victim precautions and inducing optimal activity levels).156 These
153. Guido Calabresi & Alvin K. Klevorik, Four Tests for Liability in Torts, 14 J. LEGAL STUD. 585, 590 (1985). 154. See Omri Ben-Shahar, Informed Courts, Uninformed Individuals and the Economics of Judicial Hindsight, 151 J. INSTITUTIONAL & THEORETICAL ECON. 613 (1995). 155. For an example of a situation in which the fact of harm does not provide new information about its probability, see Calabresi & Klevorik, supra note 153, at 594-96. 156. See STEVEN SHAVELL, ECONOMIC ANALYSIS OF ACCIDENT LAW 8, 11, 14, 23-24 (1987) (analyzing rules of negligence and strict liability).

he never suggested that the expert testimony offered by the plaintiff. Thus.159) But in the area of tort law the existing responses are partial and incomplete at best. 159. See. L. 137. either underdeterrence or overdeterrence relative to correct application of the cost-benefit standard is possible. supra note 158. on file with the Stanford Law Review).g.. REV.”161 Although the judge was very active throughout the trial. 615 (1998) (quoting Graham v. as Jeffrey Rachlinski has recently pointed out. may be imperfectly applied.J. In fact the law in areas such as patent law already takes clear steps to address the problems caused by hindsight bias.. 158. the problem does not have a clear direction. rather than as they may appear in hindsight.S. REV. The litigation involved whether investment decisions involving $100 million in assets had been made in a negligent fashion.1526 STANFORD LAW REVIEW [Vol. Bayesian Fact-Finding and Efficiency: Toward an Economic Theory of Liability Under Uncertainty. we can offer clear prescriptions because the hindsight bias points in only one direction: overdeterrence (again relative to what correct cost-benefit analysis would produce). Rachlinski. 383 U. patent courts are required to guard against hindsight bias in determining whether an invention was “nonobvious” at the time of invention—despite its now (perhaps) seeming obvious—by looking to such “secondary considerations” as “commercial success. While the 157. Johnson. A Positive Psychological Theory of Judging in Hindsight. 161. which focused almost exclusively on the fact that the portfolio had lost money (rather than on the reasonableness of the investment decisions at the time they were made). Jeffrey J. L. 1986). . 1.” the court characterized as “very imaginative” defendant’s offer of testimony that “a decision based on information known at the time the decision was made can be evaluated as good or bad without regard to the outcome. long felt but unsolved need. Kip Viscusi. Rachlinski describes several existing responses. 61 S. See Rachlinski. 571. Johnson v. CAL. Although the court explicitly recognized that “[c]ase law .17 (N. Jason S. [and] failure of others”. at 61518. A colorful example is provided by litigation in which one of the present authors (Thaler) was an expert witness. 266-67 & n. See Reid Hastie & W. ties [this determination] to the circumstances extant at the time in question. it may be difficult for the court (never mind a juror) to recognize or address it.157 In contrast. since as they see it. 154-64 (1987). 515 A. may exhibit hindsight bias—although there is evidence that the bias is less for judges than juries. 160. including the negligence standard.2d 255. 65 U. Super. the law seems to acknowledge that judges. but they do not offer any clear prescriptions for addressing this problem. (Thus. . e. 50:1471 scholars have also analyzed reasons that legal rules. 1998) (unpublished manuscript. John Deere Co.160 Hindsight bias seems to be so deeply ingrained in the tort system that even when it is called to a court’s attention. Johnston. What Juries Can’t Do Well: The Jury’s Performance as a Risk Manager (May 21. In that way the evaluation is not biased by hindsight. 17-18 (1966)). . was off-target or irrelevant.158 this is in effect a limited form of debiasing of the decisionmaker. CHI. like juries.

rather they are told only about the ex ante decision facing 162. Suppose that a foodprocessing company is claimed to have decided in a negligent fashion to use a particular chemical in its production process. BEHAV. 349. 163. 40 ORG. although there is room here for future research on the role of lawyers. Baruch Fischhoff. they will be likely to overestimate the probability of harm from the chemical and. and the other general and giving rise to important avenues for future research. Unfortunately. but limited to certain sorts of cases. See. in this context the effects of hindsight bias may be exacerbated by the fact that the choice made by the defendant is an act of commission. leaving a significant gap between ex post and ex ante decisionmaking. Because of the apparent limits on debiasing. DECISION PROCESSES 40.163) Imagine. See Ilana Ritov & Jonathan Baron. imagine that the chemical ended up causing cancer in a small number of residents who live near the company’s plant. hold the foodprocessing company liable even if liability is not in fact justified under an unbiased application of the cost-benefit standard.162 The findings on the limited effect of debiasing techniques suggest that attempts by lawyers to employ such techniques may also be of limited effectiveness. Perceived Informativeness of Facts. Davies. we propose two alternative prescriptions—one simple and clear-cut. Kamin & Rachlinski. 354-56 (1977). 3 J.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1527 court ultimately accepted the “imaginative” argument of the defendant and ruled in his favor. One means of responding to the problem of hindsight bias in tort cases involves manipulating the set of information given to jurors. 61-64 (1987). & HUM. its evident surprise at the nature of the argument suggests the pervasiveness of hindsight-based thinking in the tort system. supra note 147. DECISION MAKING 263 (1990). . We know that if jurors are told that the chemical was used and ended up causing cancer. that jurors are not told that the company decided to use the chemical. BEHAV.. Martin F. such debiasing techniques appear either to have no effect on decisions or to reduce hindsight bias by only a limited degree. rather than (as would have been the case had the chemical not been used) an act of omission. 2. First prescription: Manipulate the information given to jurors.g. Reduction of Hindsight Bias by Restoration of Foresight Perspective: Effectiveness of Foresight-Encoding and Hindsight-Retrieval Strategies. (Indeed. e. thus. 3 J. The company claims that not using the cancer-causing (as it turned out) chemical would have carried significant risks to residents in terms of bacterial contamination. EXPERIMENTAL PSYCHOL. Reluctance to Vaccinate: Omission Bias and Ambiguity. at 96-98. however. How might the law respond to hindsight bias in tort cases? An obvious response is the use of jury instructions that inform jurors of the bias and tell them to focus on the ex ante situation. Prescriptions.

165. the fact of a suit may provide strong indication that the bridge was not lifted. 16 LAW & PSYCHOL. 73 OR. They learn about the benefits and costs of that strategy and must determine whether either pursuing it or failing to pursue it would have been negligent. In this sort of setting.2d 708 (2d Cir. for example. 587. Schumacher. and witnesses could not be identified as defense-side or plaintiff-side. they would not be led by hindsight bias to overestimate the probability of that harm. so that jurors deciding on liability do not learn any of the details of what happened until an initial determination of liability is made.) In some cases. 105-11 (1992). In this way it might be possible to eliminate the effect of hindsight bias on negligence determinations.1528 STANFORD LAW REVIEW [Vol. Medical Malpractice v. L. (If the decision that the defendant actually made was one that the jury determined to be negligent. could not be revealed. Richard Wiener & Joseph E. in the well-known case of Petition of Kinsman Transit Co. 1964). 50:1471 the company (whether to use the chemical). David B. since then jurors would suspect which choice was made and would tend to engage in hindsight-biased decisionmaking to the defendant’s detriment. It is also important to note that various procedural steps would have to be taken to protect the secrecy of the defendant’s choice if outcome information were to be kept from the jury. 338 F. Schipani. lawyers’ affiliations. (One might worry that the food-processing company’s employees would testify in a way that revealed what choice the company made. the fact of the suit will make clear what that choice was. REV. Poythress. Schopp. 65.164 in which a bridge operator failed to lift the bridge in time to prevent an accident. In this scenario the jurors would be transformed into ex ante decisionmakers: They wouldn’t know whether the “accident” that occurred (prompting the lawsuit) was harm from bacterial contamination or harm from the chemical.165 Although 164. Arkes & Cindy A.) It is important to note the structure of this example: The defendant faced a choice of options. In this sort of case. outcome information could be introduced for purposes of computing damages. a possible prescription (offered previously in the literature) involves bifurcation of trials. Because they would not know what harm ended up materializing. apparently because he was at a tavern. Their probability estimates for each type of harm—and their resulting assessment of whether either decision by the company would have been negligent—would be untouched by hindsight bias. jurors assessing the defendant’s conduct would not know (if they were not told) whether the harm that prompted the suit was caused by choice of the first option or choice of the second. it might not be possible to keep the defendant’s choice from the jury. Reframing the Medical Malpractice Tort Reform Debate: Social Science Research Implications for Non-Economic Reforms. But it would not be in the company’s interests to have its employees testify in such a one-sided fashion. How and When to Correct for Juror Hindsight Bias .. 633-36 (1994). Norman G. For example. Hal R. the Business Judgment Rule: Differences in Hindsight Bias. each of which could have caused harm. REV. Wexler & Robert F.

since (as proponents of bifurcated trials recognize) “the jury will undoubtedly know that they are not being asked simply to engage in an academic exercise. thus. Thus.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1529 we think this is a sensible prescription in such settings. One might imagine counteracting the effects of hindsight bias by raising the evidentiary standard (as an alternative. is that jurors will overestimate the probability that harm will occur (since harm did. occur). The determination of the probability of harm would conventionally be made under a “preponderance of the evidence” standard: If jurors think it more likely than not. either way. cases in which either revealing or failing to reveal suicide threats by a psychiatric patient could have resulted in suicide. SCI. supra note 165. 167. at 494 (emphasis in original).”166 and that (because a trial is being held) “a bad outcome must have occurred. 166. Thus. 485. If hindsight bias is unimportant. in fact. then they might well reach the correct conclusion about liability: They would overestimate the likelihood attached to the critical threshold. in cases in which jurors need not know (because they cannot infer from the fact of a lawsuit) what choice the defendant made. the prescription seems unlikely to do significant harm (from the perspective of the specified goal of achieving correct application of the ex ante cost-benefit standard). And there are many such situations: cases in which either of two options facing a physician could have caused harm or death to a patient. they are to find the defendant liable. as described above. we note that it will not eliminate the effects of hindsight bias. A further feature of our prescription here is that even if we are wrong about the effects of hindsight bias. cases in which either the use or the failure to use a new technology could have led to harm. & L. then whether jurors are told what outcome occurred should not matter. based on the evidence. it may be possible to eliminate the hindsight bias completely. Arkes & Schipani. supra note 165. The result of hindsight bias. 7 BEHAV. to the previous proposal. that the probability of harm was above the threshold level required for liability. Second prescription: Alter the evidentiary standard. but the overestimate might well be below the new required level.”167 In contrast. they should be able to make a correct ex ante determination. underdeterrence). for example. if the jurors were to find the defendant liable only if the evidence suggested at least a seventy-five percent likelihood—rather than merely a fifty-one percent likelihood—that the critical harm probability threshold was met. . the prescription should either have no effect on decisionmaking (if hindsight bias is not a problem) or represent an improvement over the current system (if hindsight bias is a problem). Wexler & Schopp. the two together would produce overcorrection and. at 635. 496 (1989). not in addition. in Mental Health Malpractice Litigation: Some Preliminary Observations.

for example. 50:1471 The highest evidentiary threshold known to our legal system—the “beyond a reasonable doubt” standard—is used only in criminal cases. But with hindsight bias.169 This need not be the case. REV. jurors will overestimate the likelihood that the negligence threshold has been met. we might well tolerate a crude measure that produced some errors so long as it represented an improvement over the current system. in some situations defendants might be found not liable when. suppose that jurors generally overestimate by fifty percent the likelihood that the negligence threshold is met. and this will produce an upward shift in the function we are imagining. 169. 110 HARV. To see this point. 1408. in civil cases an intermediate standard (higher than the preponderance standard. 1531 (1997). and even if it is. L. To fix ideas for purposes of exploring these points. at 606-07. But if that line itself is shifted up by an appropriate amount. supra note 158. See Developments in the Law—The Civil Jury.) This. (Of course. the overestimation of the likelihood that the negligence threshold is met could in theory be precisely offset by a change in the evidentiary threshold.1530 STANFORD LAW REVIEW [Vol. (So. under a perfectly functioning system with no hindsight bias and no heightened evidentiary standard. as a result. In the absence of hindsight bias. Our goal is to suggest the value of research on this issue. too many cases will cross the preponderance line. This standard has been adopted by many states for punitive-damage determinations. the hindsight-influenced function will cross it at precisely the same level of evidentiary strength as the one at which the original function crossed 168. See Rachlinski. they would be found liable. rather than to urge an immediate change in policy based on what we now know.168 and a broadening of its use to all negligence determinations—or at least those in which hindsight bias seems most likely to present a significant problem—might provide a desirable counterweight to the tendency of jurors to overestimate the probability that harm will occur. the function will cross the fiftypercent (preponderance) cut-off at a given level of evidentiary strength. imagine first that hindsight bias produces a similar increase across cases in a juror’s perceived likelihood that the negligence threshold is met. would be likely to be a second-best solution. and all cases in which the evidence is stronger than that should produce findings of liability. there is much room for research focused on determining whether altering the evidentiary threshold would represent a desirable response on balance—either across the board or in particular categories of cases. Most importantly. . of course.) In this circumstance. However. based on the evidence presented. imagine that the likelihood that the negligence threshold has been met is graphed as a function of the strength of the evidence. however. further study would be required before reaching a final conclusion here. but less demanding than the “beyond a reasonable doubt” standard) is the “clear and convincing evidence” standard.

Y. if the likelihood that the negligence threshold has been met is a linear function of the strength of the evidence. 458 F. For instance. and jurors overestimate by fifty percent the likelihood that the threshold is met.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1531 the preponderance standard. United States v.) But as far as the second prescription is concerned. Fatico. then a shift to a higher evidentiary standard might result in underdeterrence of some defendants (specifically those whose actions will not be judged in a particularly hindsightbiased way). 410 (E.170 (Of course. but simply that they want to compensate tort victims.N. The same response may be offered to the objection that jurors’ behavior is not sensitive to the evidentiary threshold—a point on which there is 170. But as long as the increase in the evidentiary standard is modest relative to what hindsight bias in the average case warrants. regardless of a higher evidentiary threshold. But there is no reason to think the existence of a higher threshold will make things worse in this situation. 388. a survey of federal district court judges found that in the judges’ view that standard requires a likelihood of sixty to seventy percent. would have to say that the company was negligent whether it used the chemical or refrained from using it—probably not a likely scenario. And the change from a move to the “clear and convincing evidence” standard would be a relatively modest one. Our first prescription addresses the latter issue as well as the former.D.) One response to this analysis is that the reason jurors tend to find defendants liable even when liability is not legally warranted is not that jurors overestimate the probability of harm. more interesting would be data on how jurors view the two standards. compared to the fifty-one percent threshold under the preponderance standard. half of all cases in the system meet the threshold under the preponderance standard. the problem of compensation-based decisionmaking remains. If hindsight bias produces different degrees of distortion in jurors’ probability estimates across different types of cases. (In the case of the food-processing company discussed above. the change would produce fewer “underdeterrence errors” (findings of no liability for defendants who should be found liable) than corrections of “overdeterrence errors” (findings of liability for defendants who should not be found liable). the jurors. it is difficult for them to engage in compensation-based decisionmaking. So if this is what is going on. jurors may continue to find defendants liable. . 1978). Supp. moving to the higher evidentiary threshold may improve decisionmaking. then a move to a seventy-five-percent likelihood requirement would result in the jurors’ finding negligence in precisely the half of cases in which it should be found. to ensure compensation for the harm that occurred. and so as long as there are some cases in which jurors try faithfully to apply the negligence standard. for if jurors do not know what harm occurred.

173 A public defense of such steps is perfectly intelligible. As just one example. In both private and public life. Other applications. Decisionmakers in such a case are required to make an after-the-fact determination of whether a reasonable ex ante decisionmaker would have thought the prospective issue or problem “material” to the average shareholder based on the 171. so therefore we raise the threshold to clear and convincing evidence. we know that you are likely to think irrationally.1532 STANFORD LAW REVIEW [Vol. whose perceived excesses prompted Congress to enact the Private Securities Litigation Reform Act of 1995. EVID. and that their basis and content must not be secret. JOHN RAWLS. 109 Stat. KADISH & STEPHEN J.). SCHULHOFER.174 In a typical securities fraud case. 174. Compare Dorothy K. Legal vs. roughly. Clark Stanton. 3. BEHAV. 404(b). take steps to ensure against their own tendencies to make mistakes. No. One example is securities fraud litigation.S.) Raising the standard of proof to prevent errors is consistent with much of the law of evidence. in an idea of this sort. which is also designed to respond to cognitive errors. L. 9 LAW & HUM. . and they are required to assess whether a particular issue or problem facing the company.171 as long as an increase in the threshold will matter in some cases. 173.172 The question is whether it is coherent to tell jurors that: Although this case should be decided by the preponderance of the evidence. consider the restrictions on admission of evidence of prior crimes. The discussion to this point has focused on tort cases decided under the negligence standard. R. This issue was raised by Jon Elster in comments on an earlier draft of this article. people. whose disclosure prompted the fall. Quantified Definitions of Standards of Proof. 104-67. that principles of justice must be defensible publicly. or violative of the publicity condition. (We discussed in Part I. FED. Pub. CRIMINAL LAW AND ITS PROCESSES 40 (6th ed. with SANFORD H. which means. We do not believe that there is anything incoherent. A final objection might be that altering the evidentiary standard would not (it is claimed) survive the Kantian-Rawlsian publicity condition. 172. acting individually or in groups. 50:1471 conflicting evidence. 737 (1995) (codified in scattered sections of 15 U. Kagahiro & W. should have been disclosed at an earlier stage (typically before it had become an issue or problem). decisionmakers are confronted with a company whose stock price experienced a dramatic fall. 162-65 (1985) (finding no effect of different evidentiary thresholds).A the steps that people frequently take to deal with problems of bounded willpower. since there is no reason to think it will cause harm in cases in which it does not change jurors’ behavior. 159.C. 1995) (citing studies that find such an effect). the change may be desirable. but similar issues may arise in other areas of law in which juries (or judges) must determine whether an ex ante standard was met while armed with the knowledge that a negative event in fact materialized. A THEORY OF JUSTICE 133 (1971).

ECONOMICS OF THE PUBLIC SECTOR 90-91 (1986). 178.4 (1986). 511-13 (1991). Rubin.175 The problem is that this determination must be made against the backdrop of knowledge that the issue or problem in fact materialized. and produced a large drop in the company’s stock price. L. JOSEPH E. CORPORATE LAW § 8. REV. or through provision of information by the government itself. providing additional information to citizens. not whether the company’s behavior was reasonable from an ex ante perspective.J. B. 144 U. See ROBERT CHARLES CLARK.10. 497. the main predictor of whether a securities fraud action is brought seems to be whether there has been a large change in the company’s stock market value. or the effects of drug use. See. Suppose it is agreed that individuals lack adequate information on a given subject—for example. Do the Merits Matter? A Study of Settlements in Securities Class Actions. PA. in other instances the government may have a specific policy goal (reducing drug use. a decisionmaker will likely find it difficult to see how a reasonable ex ante decisionmaker might have thought the prospective issue or problem other than material. A risk in such suits is that if the allegedly illegal search did in fact produce damaging evidence (say. 175. e. measured the same way177). This will be true even if. 235-36 (1991). 80 GEO. either through a mandate to the relevant private actors (for instance. workplace safety. 903. Background. employers).178 The prescription to “provide more information” is striking in its spareness. STIGLITZ. REV. and it often advocates. Conventional economics acknowledges the possible desirability of each of these goals (the second in the case of phenomena such as externalities). drugs or other contraband). encouraging the use of energyefficient refrigerators). 979-80 (1996). See Janet Cooper Alexander. this behavior would not have been found reasonable. Information Disclosure and Government Advertising 1. 177. which requires lenders to announce interest rates. L. 43 STAN. 93540. 176.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1533 information available at the time.g. 223.176 Another example here involves damage suits for violations of the Fourth Amendment.. from an ex ante perspective (without knowing the eventual outcome). See Edward L. Fraud in the New-Issues Market: Empirical Evidence on Securities Class Actions. then decisionmakers are likely to conclude that the law enforcement agency’s behavior was reasonable. In some such instances the government may seek to foster comparison shopping and informed decisionmaking (as in the federal truth-in-lending law. as a means of achieving them. L. In this situation. appliance energy efficiency. Consistent with this analysis. Legislative Methodology: Some Lessons from the Truth-inLending Act. . Behavioral analysis suggests that this prescription is far too spare. James Bohn & Stephen Choi.

” We discuss several examples of this below. 8. Magat & Joel Huber. Shlomo Benartzi & Richard H. that this will matter a great deal. W. Defined Contribution. 630-36 (1996). See Christine Williamson. W. the Labor Department. but firms are not allowed to offer “advice” as to how to invest. 5.. Consider in this connection a recent study of the division of retirement savings by university staff employees between two different funds. while the other was given a simulated distribution of thirty-year rates of return. and yet we know from much of what has been said already. e. DOL Moves Help Sponsors. 477-78 (1987). one group was given the distribution of oneyear rates of return. 180. See. as well as from empirical work by scholars such as W. An Investigation of the Rationality of Consumer Valuations of Multiple Health Risks. PENSIONS & INVESTMENTS. for example. since there is often no “neutral” way to present information. 181.1534 STANFORD LAW REVIEW [Vol. One is “antiprescriptive”: Prescriptions directed toward fostering comparison shopping—the first government goal mentioned above—will often be incomplete and may even be paralyzing. 1997) (unpublished manuscript. 48 RUTGERS L. Kip Viscusi. has ruled that employers must give employees investment alternatives. . That presentation matters has several implications. Those shown the thirty-year returns elected to invest nearly all their savings in stocks. ECON. Our point is not that one of 179. but this information was displayed in two different ways. a safe one (bonds) and a risky one (stocks). 18 RAND J.g. Individual Rationality. Kip Viscusi. and the Foundations of Tort Law.180 We think that such spare guidelines place employers in a very difficult position. at 27. 2. REV. Feb. It is not enough simply to “provide information. Thaler. 1996. 625. Risk Aversion or Myopia? Choices in Repeated Gambles and Retirement Investments (Nov. 50:1471 “Provide more information” says nothing about the way in which the information will be provided.179 Thus. while those shown the one-year returns invested a majority of their funds in bonds. the relevant government authority. The reason is that the way firms decide to describe and display information on investment alternatives will have a powerful impact on the choices employees make. on file with the Stanford Law Review). we know that people’s perceptions of the probability of uncertain events is influenced by the salience of the presentation of these events. and must provide information about those alternatives (such as risk and returns).181 All the employees were shown actual historical data on the returns of the two funds. Kip Viscusi. Antiprescription. Consider the following example of a government attempt to foster informed decisionmaking: In the case of defined contribution plans such as 401(k)s. The second implication is that effective prescriptive strategies for achieving the second goal mentioned above—discouraging particular types of behavior—must take behavioral factors into account. Wesley A. 465. But New Proposals Raise Concerns at P&I Conference. Hazard Warnings.

at 277-79. The actors subject to the mandate will often have an interest in providing the least scary. one of the central features of Kahneman and Tversky’s prospect theory is that people evaluate outcomes based on the change they represent from an initial reference point. In terms of the shape of the “value function” for decisionmakers (a function giving the value of each outcome–this is prospect theory’s counterpart to the utility function). id. 183. See Kahneman & Tversky. This shape of the value function is further supported by evidence of attitudes toward risk: People appear generally (though there are exceptions) to exhibit risk- . Bertram Scharf & Joseph C. if the goal is accurate knowledge. “exposure to benzene will increase your risk of getting CANCER and other FATAL diseases”).183 The evaluation of outcomes in terms of gains and 182. at 273 (outcomes are viewed differently depending on whether they come in the form of gains or losses from a perceived status quo). Of course. In still other contexts. only with that shape are both gains and losses viewed as less significant the further the decisionmaker is from her reference point. for example. the best message in this case. suppose that the prescription is that certain private actors be required to provide “information”. at 279 (citing Eugene Galanter & Patricia Pliner. rather than based on the nature of the outcome itself.” It is not even clear that there are steady or stable background preferences that might be “informed. 1974)) (losses are weighted more heavily than gains). This is an example in which the prescription to “provide more information” may be paralyzing. this suggests a function that is concave for gains and convex for losses. while regulators might want the most scary. Moskowitz. both for gains and for losses. Thus. both empirically and under prospect theory.” The preferences can themselves be an artifact of the method of informing. she who provides information ends up giving advice. such as ones in which the presentation of information will affect people’s preferences rather than just their perceptions of risk. salient message available (say. Cross-Modality Matching of Money Against Other Continua. Another feature of how outcomes are viewed. Stevens eds. losses from the initial reference point are weighted much more heavily than gains. assuming a reference point of $0. Thus. is that a given change produces less reaction the further a decisionmaker is from her reference point. For instance. most pallid version of the information possible (for example. what does this mean? If it means that those who expose people to a dangerous substance or product in the workplace (say benzene) must provide them with accurate information about the danger.. this leaves open a tremendous range of possibilities. See id. “benzene has been associated with a statistical increase in risk”). it is not even clear in theory what is meant by ensuring “informed decisionmaking.182 This aspect of prospect theory (like its other features) is based on evidence about actual choice behavior. See id.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1535 these outcomes is better. in other instances it may simply be incomplete. may well be somewhere in between. at 278. also. See id. Our point is simply that in the real world. the value difference between $10 and $20 is greater than the value difference between $1000 and $1010. An important goal of the analyst’s task in making prescriptions in this area is to say how the information should be provided— not just that it should be provided. supra note 12. in SENSATION AND MEASUREMENT 65 (Howard R.

Below we develop briefly some specific prescriptions for achieving goals that involve changing people’s behavior. Prescriptions. 185. Kochenberger. Framing the Jury: Cognitive Perspectives on Pain and Suffering Awards. Suppose now that the agreed-upon goal is not to foster “informed decisionmaking.” (Other. First prescription: Exploit loss aversion. means that it matters a great deal whether something is presented as a gain or a loss relative to the status quo. 1341 (1995) (finding effect of gain versus loss framing on magnitude of damage awards). at 268. and these attitudes imply concavity of the value function for gains and convexity for losses. as one possible means. As just noted. there is of course an enormous marketing literature about how best to shape people’s behavior in desired directions. Thaler.1536 STANFORD LAW REVIEW [Vol. Fishburn & Gary A. Spitzer. 91. context-dependent. probably more usual. 184. REV. Amos Tversky & Richard H. 509-10 (1979). conventional economics would again prescribe. though. 278. framing consequences in terms of losses rather than gains is likely to be far more effective in changing behavior. There is nothing surprising about this statement. coupled with the special aversion to losses. 10 DECISION SCI. Kahneman & Matthew L.) Quite obviously. preferences are not preexisting but rather “constructive. a perceived threat of a loss relative to the status quo weighs more heavily than a perceived threat of foregoing a gain. in THALER. Likewise. at 79. some ways of providing information are more effective than others. supra note 40.” but to discourage particular types of behavior. they think they are getting something for their money.185 A well-known illustration of this sort of framing averse attitudes towards gains but risk-seeking attitudes toward losses. Peter C. individuals tend to weight losses far more heavily than gains. . See id. Presumably. And to achieve this goal. L. In such cases it is difficult to say which individual is “informed”—the one who is told of the perceived threat of a loss or the one who is told of the perceived threat of foregoing a gain. These points apply equally to the government. when firms pay millions of dollars to advertising agencies to create splashy new ad campaigns. As a result. means include taxation and regulation designed to discourage the unwanted behavior. See id. 503.184 3. Cf. Conventional economics would view this as a desirable goal at least to the extent that fullyinformed consumers would not engage in the behavior in question. McCaffery. Preference Reversals. “more information. In this and other contexts. This pattern of concavity and convexity has received considerable empirical support. 81 VA. Two-Piece Von Neumann-Morgenstern Utility Functions. 50:1471 losses from an initial reference point.” analogous to the balls or strikes that do not predate the situation of choice and that “ain’t nothing till” the umpire calls them. Edward J. Daniel J. and to an even greater extent if the behavior in question produces externality effects.

LEGAL F. 9. supra note 152 (overoptimism apparent in the general public). L. 863 (1996) (citing Mathea Falco. “this is your brain on drugs. 505 (1987). 1994 U CHI.189 What does this feature of behavior imply about government provision of information? Consider the choice between a safe-driving campaign focused on drivers’ own driving and the ingenuous campaign actually adopted by the government: “Drive defensively: Watch out for the other guy. 18 LOY. The Effect of Message Framing on Breast SelfExamination: Attitudes. but there are significant changes in behavior from pamphlets that stress the negative consequences of a refusal to undertake self-examinations (women who fail to perform such examinations have a decreased chance of finding a tumor at a treatable stage).May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1537 effect is a study involving breast self-examination. Unrealistic Optimism. responded to the fact that most people tend to believe that they are unusually safe drivers.188 This behavior is not specific to the young. RICHARD A. POSNER. . Second prescription: Exploit salience. 52 J. 186. people will tend to respond to it by attaching a higher probability to the event in question. as Richard Posner has suggested. 189. Comment. This sort of information has a high degree of salience. See note 152 supra and accompanying text. 841. Effective prescriptive strategies need to take account of the fact that vivid and personal information will often be more effective than statistical evidence. Third prescription: Avoid the pitfalls of overoptimism. Getting High from South of the Border: Illicit Smuggling of Rohynol as an Example of the Need to Modify U. women who undertake such examinations have a greater chance of finding a tumor at a treatable stage) are ineffective. Thus an antidrug advertisement. 187. a common feature of human behavior is overoptimism. 500.J. INT’L & COMP.186 Note that this example illustrates how the provision of information may be a more natural tool than taxation or regulation for discouraging some forms of behavior (such as the failure to perform a self-examination). pamphlets describing the positive effects of breast self-examination (for example. although it may be diminished as people move beyond middle to old age. L. at 1177. perhaps self-consciously. See Weinstein. Meyerowitz & Shelly Chaiken. 190. Intentions. AGING AND OLD AGE 104-06 (1995).S. See Douglas Herring. as a result of the availability heuristic. See Sunstein.A. Response to International Drug Smuggling After NAFTA. 188. and Behavior. PERSONALITY & SOC.”190 The government’s campaign. and. 15). PSYCHOL.” appeared to have a significant effect on behavior. supra note 3. showing a frying egg with the announcer’s voice claiming. Toward a More Effective Drug Policy. This is a model of the sort of prescriptive approach advocated by behavioral analysis. Beth E. As noted in the previous section.187 Availability suggests that the ad produced a higher perceived probability of negative effects than a flatter ad would have.

plain tickets under the windshield wiper on the curb side of the street. Consider the question of deterring criminal behavior. Another example here is “community policing. convenient for the parking officer to reach). brightly-colored tickets that read “VIOLATION” in large letters on the drivers’ side window. by making more visible and memorable the presence of police (as. so that years in prison far in 191. Behavior of Criminals 1. due to problems of self-control. and this may depend on factors unrelated to the actual probability of the event. of making law enforcement highly visible. at 1235. Mitchell Polinsky and Steven Shavell have recently suggested that potential criminal offenders may have unusually high discount rates. it suggests. by having them walk their beats rather than ride in patrol cars). holding constant the actual probability that offenders will be caught. authorities can. individuals tend to judge the likelihood of uncertain events (such as getting caught for a crime) by how available such instances are to the human mind. while the costs (if they are incurred at all) are spread out over time—often a very long time. increase the deterrence of potential criminals without altering the actual probability of apprehension.” now widely practiced across the country. See Shavell. the good sense of the familiar method of parking-ticket enforcement—sticking large. and A. Economic analysis assumes that such future costs are discounted to present value.191 Potential offenders are imagined to make at least a rough calculation of these costs and benefits in the process of making their decisions. Background. as described above. supra note 41. But even if one assumes that potential offenders can accurately compute the costs and benefits of crime. . A central feature of much criminal behavior is that the benefits are immediate. bounded willpower suggests that they will often behave in ways at odds with conventional economic analysis. Economic analysis of this question typically starts from the premise that potential offenders will be deterred from criminal acts if the expected costs of those acts exceed their expected benefits. from a prescriptive standpoint. Our discussion of prescriptive analysis has thus far focused on bounded rationality. it is suggested. where they are particularly noticeable to drivers passing by—as opposed to a less costly approach (putting small.1538 STANFORD LAW REVIEW [Vol. for example. But bounded willpower may also play a role. This analysis suggests the desirability. Bounded rationality suggests that people may make systematic (as opposed to random) errors in computing these costs and benefits. for example. for example. 50:1471 C.

May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1539 the future will be discounted very heavily.200 What does hyperbolic discounting imply for effective deterrence of criminal behavior? With this sort of bounded willpower on the part of po192. 195. A GENERAL THEORY OF CRIME 85-120 (1990) (emphasizing role of lack of self-control in criminal behavior). . JON ELSTER. 213.194 This means that impatience is very strong for near rewards (and aversion very strong for near punishments) but that each of these declines over time—a pattern referred to as “hyperbolic discounting. Golden Eggs and Hyperbolic Discounting. James Q. See. 9 JUST.’”197 Richard Posner has recently applied these ideas to issues of aging and old age.”195 Such attitudes reflect “dynamic inconsistency”. See David Laibson. 199.196 In an illuminating overstatement.193 2. this means that the difference between the attractiveness or aversiveness of a reward or punishment today versus tomorrow is the same as the difference between a year from now and a year and one day from now. 193. one’s present desires for the future are at odds with one’s future desires for the future.199 Such a need for justification would not occur with the ordinary discounting assumed by most conventional economic analysis. Wilson & Abrahamse. supra note 189. 112 Q. Prescriptions. 372-74 (1992) (similar). Thaler. A. 443.192 Behavioral economic analysis carries this idea further by incorporating self-control issues often emphasized by criminologists. See id. 1997). 196. 95-96 (discussing studies). at 84-94. Discussion Paper No. ULYSSES AND THE SIRENS: STUDIES IN RATIONALITY AND IRRATIONALITY 71 (1979). at 92.. Jon Elster has referred to this as the “absolute priority of the present”—akin to the “absolute priority [of the self] over other persons: I am I—while they are all ‘out there. As just noted. Wilson & Allan Abrahamse. Economics. supra note 40. at 374. 198. ECON. John M Olin Center for Law. supra note 193. Does Crime Pay?. Intertemporal Choice. Q. at 445. 281-82.198 and their application to criminal offenders is supported by the idea that such offenders often behave “impulsive[ly]” and then have to “exaggerat[e] the benefits of crime” in order to justify their behavior to themselves later.g. supra note 195. 197. See George Loewenstein & Richard H. 359. decisions would not be regretted later because with that form of discounting there is no dynamic inconsistency of preference. 200. MICHAEL R. ON THE DISUTILITY AND DISCOUNTING OF IMPRISONMENT AND THE THEORY OF DETERRENCE 12-13 (Harvard Law School. the existing economic analysis assumes a constant discount rate (although perhaps a high one). 44546 (1997). and Business. GOTTFREDSON & TRAVIS HIRSCHI. 194. See Laibson. POSNER.J. MITCHELL POLINSKY & STEVEN SHAVELL. there is considerable evidence that people display sharply declining discount rates. in THALER. In contrast to this theory. e.

then the ten-year term’s severity would be 325—much closer than the 201. 32 J. under which drug offenders on probation or parole would be swiftly and automatically punished. and thus a lack of self-control in the sense used here. in fact. Coerced Abstinence: A Neopaternalist Drug Policy Initiative.203 Another interesting piece of empirical evidence concerns offenders’ views of sentences of different lengths. 1997). Our analysis is consistent with empirical evidence suggesting that criminal behavior is correlated with high levels of self-control problems. One study found that they view a five-year term of imprisonment as.and ten-year term should be quite small (approximately 6 on the severity measure).5. the five-year term had a perceived severity of 200. say. 202. Id. . 113 (1995). 149. RES. 203. Mark A. 107. 204. 205-08 (Lawrence M. compared to 100 for the one-year term.201 This idea is reflected in policy recommendations such as Mark Kleiman’s “coerced abstinence” proposal. for example. behavioral economic analysis (and basic common sense) tells us that this is not so. for any positive drug result. the difference between not getting caught and being imprisoned for. but with modest sanctions. Cooter. William Spelman. L. Short punishments will thus have much more effect than long punishments as a result of the “priority of the present”. Regulating Traffic Safety. Robert D. CRIME & DELINQ.1540 STANFORD LAW REVIEW [Vol. & ECON. but for a different reason. 203. and Akrasia in Torts and Crimes: Towards an Economic Theory of the Will. 192 (1990). 50:1471 tential offenders. 11 INT’L REV. the difference was 300.25 weight on all years after the first year (so that the five-year term’s severity is 100 + 25 + 25 + 25 + 25 = 200). a year differs dramatically from the difference between being imprisoned for ten years and being imprisoned for eleven years (even apart from any fixed costs that may accompany the fact of conviction). Mead ed. Conflict.R. Michael Trebilcock & Kent Roach.205 This difference is also somewhat higher than hyperbolic discounting would suggest.202 Short punishments are also desirable under Polinsky and Shavell’s approach. The Severity of Intermediate Sanctions. It appears. that drunk-driving behavior is significantly correlated with not wearing a seat belt—itself a behavior that seems to suggest a very high weight on the present. Lapses. on average. Kleiman. in SECURING COMPLIANCE: SEVEN CASE STUDIES 165. if the difference between 100 and 200 represents a . 205. 154 (1991) (concluding that short but highly probable sentences are optimal in a model in which potential offenders experience “lapses” in self-control). See Martin Friedland.. in THE NEW PATERNALISM 182.204 This alone is also consistent with a high discount rate—a rate of roughly 0. only twice as bad as a oneyear term. Cf. adding years onto a sentence will produce little additional deterrence. the difference between a five. While the standard theory says that these two things differ only insofar as the costs of imprisonment in year eleven must be discounted to present value in order to be compared with the loss of wages and personal freedom in year one. But with that discount rate.

Levitt. at 1178. call into question the idea that intervention by government actors. are thought to be the best judges of what will promote their own welfare. Yet many of the instances of bounded rationality discussed above call this idea into question—and also.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1541 206 predicted by the nonhyperbolic approach. NORMATIVE ANALYSIS: ANTI-ANTIPATERNALISM In its normative orientation. however. Levitt. The idea of “consumer sovereignty” plays a large role. although still less than the actual severity rating of 500. Using Electoral Cycles in Police Hiring to Estimate the Effect of Police on Crime. These data are of course only suggestive. citizens. since these harms may not be very salient. 87 AM. The Effect of Prison Population Size on Crime Rates: Evidence from Prison Overcrowding Litigation. Similarly. REV. by creating norms that solve collective action problems even without government intervention.207 We also note (although we do not explore this point here) that while bounded rationality may increase the need for law (if government’s failings are less serious than citizens’).206 A full analysis of criminal behavior would also need to incorporate other factors not considered here (such as the role of community). 207. . In this way bounded rationality pushes toward a sort of antiantipaternalism—a skepticism about antipaternalism.J. we have not shown that the bounded willpower approach leads to improved predictions of actual criminal behavior. the risks from poor diet). but scholars such as Steven Levitt have begun to demonstrate the possibilities in this area. Steven D. ECON. conventional law and economics is often strongly antipaternalistic. assuming they have reasonable access to relevant information. if people are boundedly self-interested. our goal is only to sketch some of the many ways in which conventional economic analysis of criminal law can be usefully extended using the tools of behavioral economics. A standard argument for law under the conventional economic approach is that selfinterested people will create collective irrationality. the effect of salience may lead to substantial underestimation of certain risks encountered in everyday life (for example. overoptimism leads most people to believe that their own risk of a negative outcome is far lower than the average person’s. 206. Empirical work on actual behavior of this sort is notoriously difficult. Citizen Error Many of the forms of bounded rationality discussed above call into question the idea of consumer sovereignty. 270 (1997). 111 Q. supra note 3. can improve matters. Steven D. ECON. See Sunstein. 208. as we will emphasize below. V. this problem may tend to disappear. but not an affirmative defense of paternalism. who themselves may face the same cognitive or motivational problems as everyone else. 319 (1996). bounded self-interest may reduce it.208 A. For example.

for example. New Challenges to the Rationality Assumption. 210. Bazerman. 211. or at least as a proposition that could not be falsified. 917 (1978).210 Even if people can obtain accurate statistical knowledge. but does this mean that disease is a less severe problem than prior attitudes would 209.1542 STANFORD LAW REVIEW [Vol. in HEDONIC PSYCHOLOGY: SCIENTIFIC APPROACHES TO ENJOYMENT. in THE RATIONAL FOUNDATIONS OF ECONOMIC BEHAVIOUR 203 (Kenneth J. through coping mechanisms. supra note 3. Thus. 214. 47 DUKE L. PSYCHOL. they are ones of insufficient ability to process accurately the information one possesses insofar as that information bears on one’s own risks. Mark Perlman & Christian Schmidt eds. Further questions about the idea of consumer sovereignty arise from the gap between “decision” and “experience” utility. (forthcoming 1998). AND BEHAVIOR: THE PSYCHOLOGY OF ENVIRONMENTAL VALUATION AND DEGRADATION 52.. See Paul Slovic. 213. a point that may bear on law and policy in such areas as global climate change.209 but this does not at all imply that they have adequate perceptions of the risks of smoking that they themselves face. it is just that having information per se does not automatically imply optimal behavior. ETHICS. forthcoming 1998).. Predicting Reactions to Environmental Change. in the sense that people are sometimes unable (even apart from the sorts of informational issues recognized by conventional economics) to assess what the experience will actually be like. The utility of actual experience may diverge from the anticipated utility as revealed by people’s decisions. people may underestimate risks substantially. in ENVIRONMENT. .211 It does not follow from this that information is useless. Dan Coates & Ronnie Janoff-Bulman.214 But this suggestion about adaptation raises a complex normative question: Is a person’s measure of welfare after (for example) becoming ill the appropriate measure of value? Perhaps people. Arrow. Wouldn’t It Be Nice? Predicting Future Feelings. at 1184. 64-65 (Max H.. are able to adapt to disease better than they anticipate in advance. for example. Do Adolescent Smokers Know the Risks?. people appear not to predict accurately the consequences of becoming seriously ill or disabled. See Sunstein. See W. Lottery Winners and Accident Victims: Is Happiness Relative? 36 J. KIP VISCUSI. 50:1471 When overoptimism is combined with salience. Norbert Schwartz & Daniel Kahneman eds. SMOKING 4 (1992). See Philip Brickman. Thus. PERSONALITY & SOC. David M. See George Loewenstein & Shane Frederick. Messick. 1997). Ann E.212 The identity of decision and experience utility in conventional economics is often treated as an axiom. 1996). people may have reasonably adequate information about the risks of smoking. But behavioral research shows that people’s judgments about their future experience at the time of decision can be mistaken. statistical knowledge may not be enough to inform actual choices. See Daniel Kahneman. SUFFERING. AND WELL-BEING (Ed Diener.213 They tend to underestimate their ability to adapt to negative changes. George Loewenstein & David Schkade. 212.J. Tenbrunsel & Kimberly A. Enrico Colombatto. We emphasize that these problems are not ones of insufficient information per se. Wade-Benzoni eds.

See Robert C.216 The effects of social interaction may even make government action worse. for example.217) Thus. this phenomenon raises serious problems for the idea of consumer sovereignty. But populist government is not the only worry. Behavioral Bureaucrats Any suggestion that the government should intervene in response to people’s mistakes raises the question whether the government will be able to avoid such errors. based heavily on pressures coming from citizens.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1543 have suggested? On conventional utilitarian grounds. and more dangerous. Government will often be subject to cognitive and motivational problems even if it is not populist. SOUR GRAPES: STUDIES IN THE SUBVERSION OF RATIONALITY (1983). Clark. COMMODITIES AND CAPABILITIES (1985). as the cognitive errors that ordinary people make are replicated in statutory and administrative law. The pollutant-of-the-month syndrome in environmental law is paralleled by many measures responding to the crisisof-the-month. may tend to be subject to the very same biases and errors that afflict citizens. AMARTYA SEN. supra note 137. . and heighten. at 76072. (Thus behavioral analysis complements existing accounts of the problems with populism. REV. But a well-established challenge to utilitarian analysis suggests the possibility of a negative answer. discussed in Part III. the actions of such a government. Elites. These difficulties with populist government also point to problems with the referendum process. See W. The prospects for productive and useful intervention may be smallest in the case of populist government. VISCUSI. irregular perceptions of risk by ordinary people may tend to produce irregularities in regulation. on the ground that subjective experience may not be all that counts. Noll & Krier. the subjective experience is what counts. L. there is a good deal of synergy between behavioral mechanisms and interest group leaders. 216. the answer is probably affirmative. See JON ELSTER. 217. there is no necessary reason to think 215. B. and Traditions in the Making of Corporate Law. at 85-88. by advocating anecdote-driven policy. Contracts. and public sector availability entrepreneurs can take advantage of. FATAL TRADEOFFS: PUBLIC AND PRIVATE RESPONSIBILITIES FOR RISK 149 (1992). 89 COLUM. (Bureaucrats may also lack appropriate incentives to make decisions in the public interest. 94-97. this effect. and on conventional grounds.215 What we mean to suggest here is a simple point: People sometimes do mispredict their utility at the time of decision.) An example of the effects of populism is the Superfund statute. supra note 137. KIP VISCUSI. Thus public choice accounts of legislation can work productively with behavioral accounts. many of whom are amateur (or professional?) behavioral economists. 1703. than individual errors. 1719-20 (1989). Our earlier discussion suggests a possible mechanism: Availability entrepreneurs in the private sector can heighten the demand for regulation.C.

RISK (John D. perhaps distortions in people’s decisionmaking can be overcome by information campaigns falling well short of coercion. Imagine that sunlamps are being sold in an unregulated market and that it is learned that many consumers fall asleep under the lamps.1544 STANFORD LAW REVIEW [Vol. 220. BREYER. consider Justice Breyer’s plea for an insulated body of specialized civil servants. combined with knowledge of behavioral economics. 50:1471 that government officials are. RISK VS. Let’s call this an “unintended risk. a degree of insulation from populist pressures. . able to avoid overoptimism or predict experience utility. Each of the solutions stated in the text may also be attractive to conventional economists on a variety of grounds. Graham & Jonathan Baert Wiener eds. All we suggest is that an important part of the analysis involves asking whether the cost of requiring this safety-promoting feature (twentyfive cents per customer) is less than the cost of the unanticipated burns. might debiasing techniques work to link the statistical evidence with the personal reality? All of the foregoing ideas raise many complexities. rightly conceived. consider the following simple illustration of their application. supra note 139. although perhaps only some failed to appreciate the risks of falling asleep). by virtue of their offices. Application of these ideas to any specific topic in law would require a much fuller development of many issues than the space in this article permits. and that manufacturers have not included this feature because consumers do not anticipate that they will need it. Nor do we address possible distributive issues (all will pay more for sunlamps.. Consumers make this mistake in spite of warnings included on the package and in the instructions. For instance.” meaning a risk that consumers fail to appreciate. for example.218 Howard Margolis’ behaviorally-informed suggestion that government should be required to ensure that all initiatives “do no harm”. understood in a behavioral light as an attempt to overcome biases and confusions in both perception and motivation. DEALING WITH RISK 165-89 (1996). 218. might produce some improvement.220 We also emphasize that government intervention need not come in highly coercive forms. 1995).219 even proposals for cost-benefit analysis. Suppose. at 55-81. 219. burning themselves badly. that an automatic timer can be added to the sunlamp at a cost of twenty-five cents. New institutions may play a role. entrusted with the job of comparing risks and ensuring that resources are devoted to the most serious problems. HOWARD MARGOLIS. The existence of this unintended risk leaves open the possibility of welfareenhancing regulation. in the contexts of risks such as smoking. But we need not leave the ideas in purely abstract form. and we have not even touched upon the complicated philosophical literature on the legitimacy of paternalism. On the other hand. We do not discuss here the issues raised by the possibility that a government mandate of the timer interferes with freedom. perhaps because they fail to anticipate that lying in a warm place with one’s eyes closed is likely to induce sleep.

and assessment of costs and benefits. and this concern and their self-conception can lead them in the direction of cooperation at the expense of their material self-interest (and sometimes spite. should replace assumptions that beg the underlying questions. and one of our principal goals has been to outline areas that could benefit from further work.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1545 A central point of this example is that from the perspective of behavioral law and economics. These assumptions are sometimes useful but often false. It has been said (we believe by Herbert Simon) that economics makes things hard on agents. not questions to be answered on an a priori basis. People also have bounded willpower. People display bounded rationality: They suffer from certain biases. they follow heuristics. even strangers in some circumstances. also at the expense of their material self-interest). does the opposite. but easy on economists. . They are concerned about the wellbeing of others. that lead to mistakes. Most of these bounds can be and have been made part of formal models. We have insisted on the value and importance of using the three bounds in the economic analysis of law. both analytic and empirical. such as overoptimism and self-serving conceptions of fairness. we have explored a series of legal problems in which the bounds may be significant. this is a question to be answered based on evidence. What we are suggesting is that facts. We recapitulate here some of the reasons we think the enriched model is worth the trouble for those interested in the economic analysis of law. and they behave in accordance with prospect theory rather than expected utility theory. They take steps to overcome these limitations. more tentatively. we suggest. Of course the case for intervention is weakened to the extent that public institutions are likely to make things worse rather than better. behavioral economics. CONCLUSION Traditional law and economics is largely based on the standard assumptions of neoclassical economics. In this article we have sketched some of the implications of enriching the traditional analysis by incorporating a more realistic conception of human behavior. people are (fortunately!) boundedly self-interested. such as availability. Solving optimization problems is usually easier than describing actual behavior. We do not doubt that replacing the simple maximizing model of economics with a more complicated psychological treatment comes at some cost. issues of paternalism are to a significant degree empirical questions. No axiom demonstrates that people make choices that serve their best interests. they can be tempted and are sometimes myopic. Obviously there is a great deal of research to be done. Finally.

Some stem from the improved predictions mentioned in point 2 above. 50:1471 1. and that this may be particularly true for certain forms of property-rights assignment (such as court orders). 2. 5. Prominent in this category are the effects of presentation. since economic theory assumes that choices are invariant to the manner in which a problem is framed.1546 STANFORD LAW REVIEW [Vol. namely optimal (or second-best) rules set by judges and rent-seeking legislation determined by selfinterested log-rolling. 4. It is also important to know that even in a world without transaction costs and wealth effects. 3. A behavioral approach to law and economics produces new questions about possible mistakes by private and public actors. it falsely predicts that the language of a media account or advertisement has no effect on behavior. mistakenly. Some of the predictions of the standard model are simply wrong. We have tried to show that many laws which are seemingly inefficient and do not benefit powerful interest groups may be explained on grounds of judgments about right and wrong. We have taken some preliminary steps in suggesting ways to reduce the costs of some of these problems. and that they are likely to think. it raises serious doubts about the reflexive antipaternalism of some economic analysis of law. A behavioral approach to law and economics offers a host of novel prescriptions regarding how to make the legal system work better. For example. people can be both more spiteful and more cooperative than traditional analysis predicts. Standard economic theories of the content of law are based on an unduly limited range of potential explanations. Cognitive difficulties and motivational distortions undermine or alter conventional economic prescriptions about the jury's role. On the other hand. Behavioral economics offers other sources of potential explanation—most prominently. These points bear on the supply of and the demand for law. perceptions of fairness. and on the behavior of agents in their interactions with the legal system. In other cases economics makes no predictions (or incorrect predictions of no effect). On the one hand. holding the information content constant. it raises equivalent questions . most notably in the context of assessing negligence and making other determinations of fact or law. In contrast. These features of the world matter greatly for making predictions and formulating policy. it is well established that people react differently to potential outcomes depending on whether they are perceived as foregone gains or out-of-pocket costs (losses). and this matters a great deal to law. that salient events are more common than equally prevalent but more subtle ones. the assignment of property rights alters the ultimate allocation of those rights.

. Instead we hope that economists and economically oriented lawyers will simply incorporate the useful findings of other social sciences. This approach will use traditional economic tools.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1547 about whether even well-motivated public officials will be able to offer appropriate responses to private mistakes and confusion. that will be needed to flesh out the behavioral approach for which we have argued here. Thirty years from now. transform economics into behavioral economics. we hope that there will be no such thing as behavioral economics. and economic analysis of law into one of its most important branches. both theoretical and empirical. enhanced by a better understanding of human behavior. and in so doing. We hope that this article will encourage others to continue the inquiry and research.

hindsight bias reference: Baruch Fischhoff. The specific behavioral mechanisms we draw upon. 1982). Bounded rationality Judgment errors 1. our applications: bargaining around court orders. they simply reflect the mechanisms we have used here. . government advertising. Winter 1997.. EXPERIMENTAL PSYCHOL. our applications: environmental legislation. failed negotiations. 3. anti-antipaternalism. Paul Slovic & Amos Tversky eds. ECON. availability heuristic reference: Amos Tversky & Daniel Kahneman. 1 J.1548 STANFORD LAW REVIEW [Vol. PERSP. at 109.. do not constitute an exhaustive list of the mechanisms that might be relevant to law and economics. as an overview of or entry to the existing research. A. It also lists the law and economics issues we analyze within each category of the framework. 2. Explaining Bargaining Impasse: The Role of Self-Serving Biases. we refer the interested reader to the text of our article for additional references on each topic. we provide a reference to the literature. Judgment Under Uncertainty: Heuristics and Biases. which are summarized here. 50:1471 APPENDIX: FRAMEWORK AND SUMMARY OF APPLICATIONS This appendix summarizes our framework for behavioral law and economics. HUM. Hindsight ≠ Foresight: The Effect of Outcome Knowledge on Judgment Under Uncertainty. PERCEPTION & PERFORMANCE 288 (1975). in JUDGMENT UNDER UNCERTAINTY 3 (Daniel Kahneman. 11 J. For each mechanism. self-serving bias reference: Linda Babcock & George Loewenstein.

New Challenges to the Rationality Assumption. anti-antipaternalism. Unrealistic Optimism About Future Life Events. PSCYHOL.. our applications: government advertising. 806 (1980). 39 J. Arrow. omission bias reference: Ilana Ritov & Jonathan Baron. 6. overoptimism reference: Neil D. . other determinations of fact or law. BEHAV. PERSONALITY & SOC. Weinstein. 4. our applications: government advertising. Decisionmaking behavior 1.May 1998] BEHAVIORAL APPROACH TO LAW & ECONOMICS 1549 our applications: negligence determinations. Enrico Colombatto. 3 J. Reluctance to Vaccinate: Omission Bias and Ambiguity. 47 ECONOMETRICA 263 (1979). Mark Perlman & Christian Schmidt eds. our applications: negligence determinations. DECISION MAKING 263 (1990). in THE RATIONAL FOUNDATIONS OF ECONOMIC BEHAVIOUR 203 (Kenneth J. inability to predict experience utility reference: Daniel Kahneman. Prospect Theory: An Analysis of Decision Under Risk. other determinations of fact or law. loss aversion reference: Daniel Kahneman & Amos Tversky. 1996). our applications: anti-antipaternalism. 5.

our applications: bargaining around court orders. Knetsch & Richard H. “hyperbolic” discounting reference: David Laibson. Golden Eggs and Hyperbolic Discounting. and Manners. B. Bounded willpower 1. Thaler. prior restraints on speech. prior restraints on speech. 1325. 50:1471 2. PERSP. bans on market transactions. endowment effect (a corollary of loss aversion) reference: Daniel Kahneman. 112 Q. 98 J. ©1998 by the board of Trustees of the Leland Stanford Junior University. mandatory contract terms. C.J. our applications: criminal behavior. Dictators. at 209. Anomalies: Ultimatums.1550 STANFORD LAW REVIEW [Vol. POL. ECON. fairness behavior and spitefulness reference: Colin Camerer & Richard H. 9 J. our applications: bargaining around court orders. Spring 1995. 443 (1997). Bounded self-interest 1. ECON. Experimental Tests of the Endowment Effect and the Coase Theorem. ECON. . 1327 (1990). Jack L. Thaler..

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