Preferences and constraints: the value of economic games for studying human behaviour.

As economic games have spread from experimental economics to other social sciences, so too have critiques of their usefulness for drawing inferences about the 'real world'. What these criticisms often miss is that games can be used to reveal individuals' private preferences in ways that observational and interview data cannot; furthermore, economic games can be designed such that they do provide insights into real-world behaviour. Here, we draw on our collective experience using economic games in field contexts to illustrate how researchers can strategically alter the framing or design of economic games to draw inferences about private-world or real-world preferences. A detailed case study from coastal Colombia provides an example of the subtleties of game design and how games can be combined fruitfully with self-report data. We close with a list of concrete recommendations for how to modify economic games to better match particular research questions and research contexts.

Church attendance and alloparenting: an analysis of fertility, social support and child development among English mothers.

Many aspects of religious rituals suggest they provide adaptive benefits. Studies across societies consistently find that investments in ritual behaviour return high levels of cooperation. Another line of research finds that alloparental support to mothers increases maternal fertility and improves child outcomes. Although plausible, whether religious cooperation extends to alloparenting and/or affects child development remains unclear. Using 10 years of data collected from the Avon Longitudinal Study of Parents and Children (ALSPAC), we test the predictions that church attendance is positively associated with social support and fertility (n = 8207 to n = 8209), and that social support is positively associated with fertility and child development (n = 1766 to n = 6561). Results show that: (i) relative to not attending, church attendance is positively related to a woman's social network support and aid from co-religionists, (ii) aid from co-religionists is associated with increased family size, while (iii) fertility declines with extra-religious social network support. Moreover, while extra-religious social network support decreased over time, co-religionist aid remained constant. These findings suggest that religious and secular networks differ in their longevity and have divergent influences on a woman's fertility. We find some suggestive evidence that support to mothers and aid from co-religionists is positively associated with a child's cognitive ability at later stages of development. Findings provide mixed support for the premise that ritual, such as church attendance, is part of a strategy that returns high levels of support, fertility and improved child outcomes. Identifying the diversity and scope of cooperative breeding strategies across global religions presents an intriguing new horizon in the evolutionary study of religious systems. This article is part of the theme issue 'Ritual renaissance: new insights into the most human of behaviours'.

Moralizing gods, impartiality and religious parochialism across 15 societies.

The emergence of large-scale cooperation during the Holocene remains a central problem in the evolutionary literature. One hypothesis points to culturally evolved beliefs in punishing, interventionist gods that facilitate the extension of cooperative behaviour toward geographically distant co-religionists. Furthermore, another hypothesis points to such mechanisms being constrained to the religious ingroup, possibly at the expense of religious outgroups. To test these hypotheses, we administered two behavioural experiments and a set of interviews to a sample of 2228 participants from 15 diverse populations. These populations included foragers, pastoralists, horticulturalists, and wage labourers, practicing Buddhism, Christianity, and Hinduism, but also forms of animism and ancestor worship. Using the Random Allocation Game (RAG) and the Dictator Game (DG) in which individuals allocated money between themselves, local and geographically distant co-religionists, and religious outgroups, we found that higher ratings of gods as monitoring and punishing predicted decreased local favouritism (RAGs) and increased resource-sharing with distant co-religionists (DGs). The effects of punishing and monitoring gods on outgroup allocations revealed between-site variability, suggesting that in the absence of intergroup hostility, moralizing gods may be implicated in cooperative behaviour toward outgroups. These results provide support for the hypothesis that beliefs in monitoring and punitive gods help expand the circle of sustainable social interaction, and open questions about the treatment of religious outgroups.

Human preferences for sexually dimorphic faces may be evolutionarily novel.

A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples.

What does God know? Supernatural agents' access to socially strategic and non-strategic information.

Current evolutionary and cognitive theories of religion posit that supernatural agent concepts emerge from cognitive systems such as theory of mind and social cognition. Some argue that these concepts evolved to maintain social order by minimizing antisocial behavior. If these theories are correct, then people should process information about supernatural agents' socially strategic knowledge more quickly than non-strategic knowledge. Furthermore, agents' knowledge of immoral and uncooperative social behaviors should be especially accessible to people. To examine these hypotheses, we measured response-times to questions about the knowledge attributed to four different agents--God, Santa Claus, a fictional surveillance government, and omniscient but non-interfering aliens--that vary in their omniscience, moral concern, ability to punish, and how supernatural they are. As anticipated, participants respond more quickly to questions about agents' socially strategic knowledge than non-strategic knowledge, but only when agents are able to punish.