  We implement nonparametric revealed-preference tests of subjective expected
utility theory and its generalizations. We find that a majority of subjects'
choices are consistent with the maximization of some utility function. They
respond to price changes in the direction subjective expected utility theory
predicts, but not to a degree that makes them consistent with the theory.
Maxmin expected utility a dds no explanatory power. The degree of deviations
from the theory is uncorrelated with demographic characteristics. Our findings
are essentially the same in laboratory data with a student population and in a
panel survey with a general sample of the U.S. population.
