Charness et al. (2007b) have shown that group membership has a strong effect on individual decisions in strategic games when group membership is salient through payoff commonality. In this comment, I show that their findings also apply to nonstrategic decisions, even when no outgroup exists, and...

This study examines why people initially give to charities, why they remain committed to the cause, and what factors attenuate these influences. Using an experimental design that links donations across distinct treatments separated in time, we present several results. For example, previous...

I discuss the measurement of world poverty and inequality, with particular attention to the role of purchasing power parity (PPP) price indexes from the International Comparison Project. Global inequality increased with the latest revision of the ICP, and this reduced the global poverty line...

We present the results of an experiment that attempts to measure the social value of groups. In the experiment, group membership is induced artificially: subjects interact with insiders and outsiders in trust games and periodically enter markets where they can trade group membership. We find...

We study a collective decision-making process in which people interested in an issue may participate, at a cost, in a meeting, and the resulting decision is a compromise among the participants' preferences. We show that the equilibrium number of participants is small and their positions are...

This paper axiomatizes a utility function for social preferences under risk. In the model, a single parameter captures a preference for equality of opportunity (i.e., equality of exante expected payoffs) relative to equality of outcome (i.e., equality of ex-post payoffs). In a deterministic...