Sam Cosaert

Revealed Preference Theory for Finite Choice Sets

The theory of revealed preferences offers an elegant way to test the neoclassical model of utility maximization subject to a linear budget constraint. In many settings, however, the set of available consumption bundles does not take the form of a linear budget set. In this paper, we adjust the theory of revealed preferences to handle situations where the set of feasible bundles is finite. Such situations occur frequently in many real life and experimental settings. We derive the revealed preference conditions for consistency with utility maximization in this finite choice set setting. Interestingly, we find that it is necessary to make a distinction between the cases where the underlying utility function is weakly monotone, strongly monotone and/or concave. Next, we provide conditions on the structure of the finite choice sets for which the usual revealed preference condition (i.e. GARP) is still valid. We illustrate the relevance of our results by means of an illustration based on two experimental data sets that contain choice behaviour from children and young adults. Copyright Springer-Verlag Berlin Heidelberg 2015 (This abstract was borrowed from another version of this item.)

Are the Smart Kids More Rational

We conducted an experiment to collect data on consumption decisions made by children of different age categories. In particular, our experiment involves unsophisticated discrete consumption choices,and we present a rationality test that is specially designed for the resulting choice data. Our firstconclusion is that, in general, the observed childrens consumption behavior is largely irrational. Next, we also investigate the relationship between the degree of rationality and the childrens characteristics.Specically, we use teacher based assessments on several personal characteristics to investigate whether and to what extent smart children tend to behave more rational. Here, our main conclusion is that it is important to recognize the multidimensional nature of intelligence to obtain a balanced insight into the effect of intelligence on rationality.

Nonparametric Welfare and Demand Analysis with Unobserved Individual Heterogeneity

This paper combines revealed preference and nonparametric estimation techniques to obtain nonparametric bounds on the distribution of the money metric utility and demand functions over a population of heterogeneous households. Our approach is independent of any functional specification on the household utility functions. Our method applies the weak axiom of revealed preference to a population of heterogeneous households. Although this does not produce the sharpest bounds, we show that it is computationally attractive and provides narrow bounds. We demonstrate the usefulness of our results by applying it to the Consumer Expenditure Survey, a U.S. cross–sectional consumption data set.

Group Consumption with Caring Individuals

We propose a novel approach to model joint consumption decisions of individuals who care for each other. We assume noncooperative interaction between the different individuals and the within-group consumption outcome critically depends on the degree of caring between the group members. By varying the degree of caring, the model encompasses a whole continuum of group consumption models that are situated between the fully cooperative model (assuming a Pareto optimal outcome) and the noncooperative model without caring (assuming a public good game with voluntary contributions). This feature is used to define a measure for the degree of cooperation within the group, which quantifies how close the observed group behavior is to the fully cooperative benchmark. We also establish a dual characterization of our noncooperative model with caring preferences: we show that the model is dually equivalent to a noncooperative model with non-caring preferences that is characterized by intra-group transfers. Following a revealed preference approach, we derive testable implications of the model for empirical data. Finally, we also use our model to analyze decisions made by dyads of children in an experimental setting. We find considerable heterogeneity in the degree of caring (or cooperation) across dyads, which correlates with assertiveness and the degree of interaction within dyads.