One-shot reciprocity under error management is unbiased and fragile

The error management model of altruism in one-shot interactions provides an influential explanation for one of the most controversial behaviors in evolutionary social science. The model posits that one-shot altruism arises from a domain-specific cognitive bias that avoids the error of mistaking a long-term relationship for a oneshot interaction. One-shot altruism is thus, in an intriguingly paradoxical way, a form of reciprocity. We examine the logic behind this idea in detail. In its most general form the error management model is exceedingly flexible, and restrictions about the psychology of agents are necessary for selection to be well-defined. Once these restrictions are in place, selection is well defined, but it leads to behavior that is perfectly consistent with an unbiased rational benchmark. Thus, the evolution of one-shot reciprocity does not require an evoked cognitive bias based on repeated interactions and reputation. Moreover, in spite of its flexibility in terms of psychology, the error management model assumes that behavior is exceedingly rigid when individuals face a new interaction partner. Reciprocity can only take the form of tit-for-tat, and individuals cannot adjust their behavior in response to new information about the duration of a relationship. Zefferman (2014) showed that one-shot reciprocity does not reliably evolve if one relaxes the first restriction, and we show that the behavior does not reliably evolve if one relaxes the second restriction. Altogether, these theoretical results on one-shot reciprocity do not square well with experiments showing increased altruism in the presence of payoff-irrelevant stimuli that suggest others are watching. (C) 2016 Elsevier Inc. All rights reserved

New methods in quantitative ethnography: economic experiments and variation in the price of equality

Journal ArticleA new method for quantitatively documenting concerns for economic fairness has the potential for identifying variation in prosociality within and across societies. Multiple dictator games conducted in two small-scale societies presented decision makers with a choice between an equitable and an inequitable payoff distribution. The games varied in terms of the type of inequality the decision maker faced and the cost to the decision maker of eliminating inequality. A novel set of statistical models directly links experimental results and player heterogeneity with the formal theory of inequality aversion. The experimental method can be generalized to allow maximum flexibility in data analysis

Pre-existing fairness concerns restrict the cultural evolution and generalization of inequitable norms in children

Many social exchanges produce benefits that would not exist otherwise, but anticipating conflicts about how to distribute these benefits can derail exchange and destroy the gains. Coordination norms can solve this problem by providing a shared understanding of how to distribute benefits, but such norms can also perpetuate group- level inequality. To examine how inequitable norms evolve culturally and whether they generalize from one setting to another, we conducted an incentivized lab-in-the-field experiment among kindergarten (5–6) and second-grade (8–9) children living in Switzerland (4′228 decisions collected from 326 children). In Part 1, we created two arbitrarily marked groups, triangles and circles. We randomly and repeatedly formed pairs with one triangle and one circle, and players in a pair played a simple bargaining game in which failure to agree destroyed the gains from social exchange. At the beginning of Part 1 we suggested a specific way to play the game. In symmetric treatments, this suggestion did not imply inequality between the groups, while in asymmetric treatments it did. Part 2 of the experiment addressed the generalization of norms. Retaining their group affili- ations from Part 1, each child had to distribute resources between an in-group member and an out-group member. Children of both age groups in symmetric treatments used our suggestions about how to play the game to coordinate in Part 1. In asymmetric treatments, children followed our suggestions less consistently, which reduced coordination but moderated inequality. In Part 2, older children did not generalize privilege from Part 1. Rather, they compensated the underprivileged. Younger children neither generalized privilege nor compensated the underprivileged

Investigating the Structure of Son Bias in Armenia With Novel Measures of Individual Preferences

Sex ratios at birth favoring boys are being documented in a growing number of countries, a pattern indicating that families selectively abort females. Son bias also explains why, in many countries, girls have more siblings and are born at relatively earlier parities compared with their brothers. In this study, we develop novel methods for measuring son bias using both questionnaire items and implicit association tests, and we collect data on fertility preferences and outcomes from 2,700 participants in Armenia. We document highly skewed sex ratios, suggesting that selective abortions of females are widespread among parents in our sample. We also provide evidence that sex-selective abortions are underreported, which highlights the problem of social desirability bias. We validate our methods and demonstrate that conducting implicit association tests can be a successful strategy for measuring the relative preference for sons and daughters when social desirability is a concern. We investigate the structure of son-biased fertility preferences within households, across families, and between regions in Armenia, using measures of son bias at the level of the individual decision-maker. We find that men are, on average, considerably more son-biased than women. We also show that regional differences in son bias exist and that they appear unrelated to the socioeconomic composition of the population. Finally, we estimate the degree of spousal correlation in son bias and discuss whether husbands are reliably more son-biased than their wives