Review: Pragmatics; Psycholinguistics; Semantics: Sassoon (2013)
Editor for this issue: Joseph Salmons
Luca Sbordone <ls593
Vagueness, Gradability and Typicality
SUMMARYSassoon's book offers the results of a comprehensive analysis of linguisticgradability in the interpretation of adjectival and nominal predicates. Thebook is primarily aimed at scholars in formal semantics, but becausepsychological literature is discussed thoroughly and a fruitful conciliationbetween psychological and linguistic approaches is explicitly attempted, itwill also be of great interest for researchers in cognitive psychology andcognitive pragmatics.
Part I is intended as an introduction to the topics of vagueness, gradabilityand typicality, both from a linguistic and a psychological perspective andwith an eye on highlighting the divergences between the two approaches. Thediscussion of the various theories is mainly critical: extant accounts arepresented and then criticized in detail. The sum of the objections is intendedto open a theoretical space for Sassoon's own proposal which is presented inthe second part of the book. Part II is a gradual introduction to the author’scomplex and complete model. The theory hinges on the proposed distinctionbetween nominal and adjectival predicates. While both are shown to beassociated with sets of dimensions, the processing of such dimensions isdemonstrated to depend on completely different strategies: a version ofprototype theory is integrated for processing nominal dimensions, whilelogical rules are invoked in the case of adjectives. With such a dichotomy,claimed to be reflected in grammar, Sassoon shows how problematic linguisticdata laid out in the first part can be accounted for. In the same way,psychological findings thought to contradict standard semantic analyses areshown to be straightforwardly predicted by the proposed model.
Chapter 1 introduces basic notions and summarizes the individual chapters.
Chapter 2 defines and explores the notions of vagueness, gradability andtypicality, including an extensive overview of the linguistic andpsychological literature, aimed at highlighting both commonalities andespecially points of contrast between the two fields. The linguisticphenomenon of vagueness is defined classically and understood as a ‘pervasivefeature of adjectives’ (21) while it is noted that usually most nominalpredicates are regarded as sharp. Gradability is a property of most adjectivalpredicates, enabling entities to possess the properties denoted by thepredicate by different degrees. Empirical tests for gradability are listed,the most prominent being compatibility with degree morphology. A crucialdistinction is made between dimensional and multidimensional gradableadjectives.
The correlation between polarity and gradability is introduced (concerninge.g. different patterns of combination with degree modifiers in positive andnegative predicates). It is shown that adjectives are typically morefelicitous than nouns in within-predicate comparison ('the table is longerthan the sofa') while conversely nouns license between-predicate comparison('the table is longer than the sofa is wide') more freely.
In line with the findings of many psychological studies, nominal predicatesare also shown to be vague, conceptually gradable (i.e. they show typicalityeffects) and associated with sets of dimensions. Sasson thus argues that thesimilarity between nouns and adjectives is stronger than the linguisticliterature usually acknowledges.
Prototype theory is supported as a better theoretical alternative to explainthe existence of nominal dimensions as compared with classic (definitional)theory of concepts.
Chapter 3 is a survey of the dominant extant accounts of gradability andtypicality and their interconnections from a linguistic perspective. Thischapter presents the popular view in formal semantics of gradability asvagueness-dependent, and shows how the semantic analysis of gradablepredicates is approached in simplified vagueness models making use ofsupervaluations. A number of problems arising from vagueness-based approachesto gradability are discusses: importantly, the morphological complexity of thecomparative form with respect to the positive form of gradable adjectives isleft unexplained. Also, the very idea that gradability is vagueness-dependentis questioned following the distinction between absolute (and presumablynon-vague) and relative (vague) gradable predicates (Kennedy (2007) Kennedyand MacNally (2005)).
Concerning the nature of the degrees associated with gradable predicates, twomain families of approaches are discusses: the ‘ordinal scale’ analysis andthe ‘interval scale’ analysis. Several problems concerning the adequacy ofboth these alternatives are raised.
Furthermore, the chapter presents treatments of polarity effects in gradablepredicates. The so-called 'extent theory' is presented and criticized andLandman's (2010) 'Supremum theory' is introduced as a more convincing (if notunproblematic) alternative.
Moreover, it is contended that standard formal semantics approaches assumethat nouns are non-gradable and that this assumption must be abandoned inlight of 'robust and pervasive' (114) evidence to the contrary. Then, theauthor turns to the critical discussion of one remarkable but still inadequateexception to this consensus view, i.e. Kamp and Partee's (1995) 'Supermodeltheory'.
Chapter 4 is a comprehensive overview of the family of psychological prototypetheories of concepts. The chapter introduces and criticizes various extantviews concerning the appropriate representation and computation of relevantconceptual dimensions in the prototype structure. In relation to classicprototype theory, competing categorization criteria are introduced.Standard-based categorization predicts the link between likelihood ofcategorization of an entity and its similarity to the prototype.Categorization based on a contrast-set accounts for the facts that sometimesmembership likelihood may be not monotonically related to similarity.
On the other hand, an exemplar theory of concepts gives importance to theseparate dimension sets of entities or subcategories. The section discussesadvantages of exemplar theory (e.g. prediction of the exemplar effects andconcept variability) and its disadvantages (e.g. failure to predictsummary-representation effects). Finally, inconsistent predictions stemmingfrom the two theories are argued to be accommodated in a more comprehensiveapproach.
The problem of the compatibility of psychological theories and formal semantictheories is discussed. Many psychological theories reject the idea oftruth-conditional semantics (Murphy 2002, Lakoff 1987), regarding phenomenasuch as conjunction fallacies, subtype effects, overextension effects ascounterexamples to truth-conditional compositional semantic theories. However,experimental findings suggest that incorporating logical rules makes a theorymore explanatory.
Finally, 'knowledge theory' is presented whereby typicality is not based onstatistical regularities (in contrast with the so called 'probabilistic view')but on prior knowledge. However, there are several problems related to therepresentation of knowledge structures.
The author criticizes experimental data, questioning the idea thatcategorization is based on typicality: she maintains that there is a 'tightcoupling' between typicality and membership, apparent dissociationsnotwithstanding.
Chapter 5 introduces Sassoon's proposed model. In contrast to extantvagueness-based models, this approach assumes a full vagueness modelexplicitly representing partiality of information and the relation betweenlearning and gradability. Degree functions are incorporated into the model ona par with denotations.
The ontology of the model is a dimension space consisting of a set of entitiesand a function mapping these entities to real numbers (degrees). Objects areidentified with 'real' not conceptual/linguistic properties (whose extensionvaries across contexts). In such a framework, proper names are not rigiddesignators, but are identified with positive or negative denotations.
The crux of the model is the characterization of the degree functions: theseare general and not predicate-specific; constrains over the scales followsfrom the characterization of the functions and need not be stipulated. Inturn, predicate dimensions are regarded as normal predicates.
For nominal concepts, prototype theory is integrated into the system. Nominalconcepts map entities to their weighted means in a set of dimensions. Foradjectives a rule-based analysis is incorporated. The distinction betweensimilarity-based and rule-based categories is well supported byneuropsychological data. It is hypothesized that such a distinction isgrammaticalized as two separate categories: nouns and adjectives. As acorollary, the theory correctly predicts that the meaning of the positivepredicate is more basic than that of the comparative.
Chapter 6 presents a vagueness model incorporating dimensions and degrees.First, recursive syntactic and semantics definitions are given. One importantcharacteristic is that the ontology of the language includes a set of mappingsfrom n-tuples of entities to degrees understood as real numbers. In such aview, 'each possible individual-tuple can be described as a unique maximal,consistent assignment of degrees, the degrees assigned to it by all of thepossible degree functions' (200).
The complete vagueness model formalizes the idea that every intermediatecontext in the model represents a possible 'real' context, representing e.g.the knowledge shared by the participants in a certain discourse. Importantly,in the model the interpretation of proper names is not rigid, by contrastpartial information about proper names is represented, making identitystatement informative. Additional notions required for the interpretation of apredicate in a total context (and discussed in the remainder of the book)include functions assigning to the predicate the relevant degree function,transformation value, standard of membership, local domain, dimension set,weight and ideal value of membership.
Chapter 7's main thesis is that the noun-adjective distinction functions as acue to how to process dimensions. Nominal predicates are associated with adimension set which is by default processed as a prototype (i.e. byaveraging). In contrast, adjectival predicates are associated with a dimensionset processed by default as a set of rules (by means of Boolean operations ofunion and intersection). It follows that, unlike nominal dimensions,dimensions of adjectives can be accessed by grammatical operators.
The proposed analysis of adjectives correlates positivity in the adjectivaldomain with universal quantification over dimensions (i.e. dimensions areintegrated conjunctively) and negativity with existential quantification (i.e.disjunctively, signaling the existence of a counterexample).
Sassoon presents results of both corpus studies and judgment experiments. Itis argued that the results generally support the proposal. The proposal iseconomic in that dimensions need to be lexically specified only for positiveadjectives, thereby explaining their cognitive prominence. The negatedcharacter of dimensions in negative adjectives explains their intuitivenegative connotation and relative complexity.
A corollary hypothesis is that, provided that nouns are less cognitivelydemanding in terms of dimension processing, across languages nouns will occurmore frequently than adjectives.
Sassoon sees the present proposal as a cluster theory without the limitsclassically imputed to cluster theories: in Sassoon's model, clusters areimplemented within an intensional and entirely compositional theory.
Chapter 8 introduces and formalizes the learning principle, the idea thatproperties of earlier acquired entities are selected for the dimension set.The choice for a full vagueness model allows to associate predicategradability with the order in which vagueness is resolved, i.e. with the orderin which entities are learnt to be part of the predicate denotation.
Psychological data is provided to support the idea that typicality of entitiesis coupled with such a learning order. Additional data shows that the learningprinciple functions as a cue to specify the relevant degree function of apredicate, especially in nominal concepts. She contends that the learningprinciple is more psychologically realistic as a default strategy ofcategorization than the probabilistic criterion advocated in classic prototypetheory. Also, the learning constraint provides us with means to account forfamiliarity effects and typicality effects in individual concepts (e.g. propernames).
Finally, the learning principle makes an intuitive prediction about negatedpredicates and negative antonyms: it accounts for the fact that the denotationof the negated concept can be contextually restricted and not correspond tothe complement of the positive predicate while retaining the intuition thatordering of entities in positive and negative categories is reversed.
Interaction between the learning constraint and standard logical rules offormal semantic theories helps making correct predictions with respect tophenomena taken to contradict these rules, e.g. conjunction fallacies andemergent features. This shows that a theory which incorporates logical rulesis more explanatory than one which refutes them.
Chapter 9 presents a fully compositional analysis for predicate constructionswith different gradability morphemes. The section thus represents a formalspecification of the proposal aimed at showing that the model is able topredict correct truth-conditions for a number of constructions involvingdegree modifiers.
With respect to polarity effects, the chapter retains the intuition that theentity ordering of a negative predicate is reversed with respect to that ofits positive counterpart. However, it is also shown that the information wehave about the kind of reversing function responsible for producing thedegrees of negative adjectives is very poor. The chapter pursues thehypothesis that the value of such a transformational constant is undetermined.Crucially, indeterminacy of the degree function of negative predicatesexplains linguistic data related to polarity, such as unacceptability ofmeasure phrase modification in negative antonyms as compared with theiracceptability in positive adjectives and in negative adjectives in thecomparative form, and the infelicity of modification with multipliers innegative adjectives.
Chapter 10 presents general conclusions, summing up the main points of theproposed model and highlighting the importance of the analysis of nominalconcepts as incorporating a version of prototype theory in the semanticrepresentation of nominal dimensions. Furthermore, it explores some of themain themes for future research in light of the results of contemporarylinguistic studies on gradability.
The first part of the book is an extremely comprehensive overview of extanttheories of gradability. Sassoon has gone to great lengths to collect, explainand critically discuss an impressive number of contending accounts. The authorexplicitly states that the aim of this first part is to 'serve as a handbookintroduction to the relevant topics' (6). However, the vocabulary is oftenrather technical even in this introductory section: a number of basic notionsare presupposed, for formal semantics and other areas. Moreover, variousextant theories are mostly only sketched, with more space dedicated tocritical discussion and elaboration of relevant objections. While this issurely a helpful strategy for highlighting the advantages of the proposedmodel compared to other accounts, it in places interferes with the clarity ofexposition. All in all, this section is an excellent sketch of a map of theterritory in which Sassoon's own theory inscribes itself and which it helps tofruitfully expand. However, as an introduction to the relevant topics, it issurely best suited for a reader with solid prior knowledge of the subjectmatter; it is hardly intended for undergraduates or beginning graduatestudents in linguistics or cognitive psychology.
Moreover, the book’s central focus is on the notion of gradability(typicality, in the nominal domain). In turn, the assumed notion ofgradability appears to encompass two distinct but related phenomena: theconceptual gradability of predicates (i.e. the potential for a predicate topermit different degrees of its application) and their grammatical gradability(i.e. the compatibility with degree morphology and modification). While theformer is entailed by the latter, and is a property of both vague nouns andadjectives (and, presumably, of arguably vague verbs, e.g. run, Morzyckiforthcoming), the latter is specific of adjectives. Gradability, on such acomprehensive understanding, is regarded as vagueness-dependent and so modeledin a full vagueness model (i.e. a complex context structure based onsupervaluationism which allows for the representation of partiality andgradual learning of information). However, the book's title notwithstanding,the problem of vagueness itself is not specifically addressed. Undoubtedly, adiscussion of the philosophical problem of vagueness and the Sorites paradoxwould have been beyond the scope of the book. Nonetheless, in line withsupervaluationism, vagueness here is reflected in the semantics and theparadoxical conclusion of Sorites reasoning is avoided by means of adjustmentsin the logical meta-theory. Because such a theoretical position is assumedand not justified, the book would have surely benefitted from a proper defenseof supervaluationism and from a critical discussions of competing theoriesconcerning the source of vagueness and its proper linguistic representation.
The second part is a significant contribution to the semantic analysis ofgradable predicates. Sassoon's main thesis is at once extremely simple andextraordinarily explanatory. Moreover, as is frequently noted in the book, thetheory has the advantage of being more economical compared to other analogoustheories, as it hinges on a simple dichotomy between the processing ofdimensions in nominal and adjectival concepts and derives from this hypothesisa straightforward explanation of a large set of linguistic data (e.g. polarityeffects, compatibility with degree morphemes, etc.). The most interestingsections of the second part are Chapter 7 ('A Degree-Function Based Typologyof Predicates') and Chapter 8 ('The Learning Principle and Complex Concepts'),where most of the theoretical hypotheses are introduced and convincinglyargued for. In particular, the introduction of the learning constraint,supported with robust empirical data, allows for an elegant explanation of howlogical rules can be implemented in a similarity-based account of nominaldimensions.
In conclusion, Sassoon's book is a cornerstone for future work on predicategradability and typicality, and more generally for all future researchesaiming to bridge the gap between semantics and psychology.