Axelrod’s (1986) evolutionary computational model of metanorms was replicated and extended. Results were generally supportive of the original, with extensions increasing the number of generations resulted in increased stability and convergence to levels not achieved in the original. Replications of the groups game (two groups differing in numbers and power) yielded outcomes that were mixed, as ...

Economic theory predicts that abortion laws affect sexual behavior since they change the marginal cost of having risky sex. We estimate the impact of abortion laws on sexual behavior by reported gonorrhea incidence. Our data panel includes 41 countries for which consistent gonorrhea data are available for 1980–2000. Compared with laws permitting abortion only to save the pregnant woman’s life o...

We model network formation when heterogeneous nodes enter sequentially and form connections through both random meetings and network-based search, but with type-dependent biases. We show that there is “long-run integration,” whereby the composition of types in sufficiently old nodes’ neighborhoods approaches the global type distribution, provided that the network-based search is unbiased. Howev...

We present an experiment investigating the effects of having an individual identified as a singleton group. The presence of a singleton group reduces trustworthiness. The majority group members discriminate against the singled out group member when they are not responsible of the distinct status of this person. When the singleton group member is identified based on negative characteristics, he ...

Various authors allege that the theory of group selection is inconsistent with methodological individualism, and therefore analysts must reject at least one of these principles. The present article argues for their compatibility. The meaning of methodological individualism is clarified, and the new version of group selection (articulated by Wilson and Sober (1994, 1998)) is explained. The two p...

This paper examines the effects of a randomized housing-voucher program on individual economic outcomes. Public housing residents who are offered relocation counseling together with housing vouchers that can only be redeemed in low-poverty areas experience a reduction in welfare receipt of between 11% and 16% compared to controls. These effects are not accompanied by changes in earnings or empl...

We study the effect of cultural differences on contributions in a public good experiment, analysing real-time interactions between Italian and British subjects in their home countries. In the first treatment, subjects play in nationally-homogeneous groups. In the second treatment, Italian and British subjects play in heterogeneous groups, knowing the nationality of the group members. In the thi...

Tipping is a multi-billion-dollar phenomenon that challenges the traditional assumption of selfish economic agents who have no feelings and do not care about social norms. This article reviews the early history of tipping and offers an economic analysis of different aspects of tipping. Using the historical evidence, it then addresses two major questions about tipping: why do people tip? And doe...

In line with the widely applied principle of just deserts, we assume that the severity of the penalty on a contract offender increases in the harm on the other. When this principle holds, the influence of the efficiency of the agreement on the incentives to abide by it crucially depends on whether actions are strategic complements or substitutes. With strategic substitutes, there is a conflict ...

We show that although the prominent centrality measures in network analysis make use of different information about nodes’ positions, they all process that information in a very restrictive and identical way. They all spring from a common family that are characterized by the same axioms. In particular, they are all based on a additively separable and linear treatment of a statistic that capture...