Cooperation and the In-Group-Out-Group Bias: A Field Test on Israeli Kibbutz Members and City Residents

The in-group-out-group bias is among the most well documented and widely observed phenomenon in the social sciences. Despite its role in hiring decisions and job discrimination, negotiations, and conflict and competition between groups, economists have paid little attention to the in-group-out-group bias. We question the universality of the bias by conducting field experiments to test whether it extends to the cooperative behavior of one of the most successful and best-known modern collective societies, the Israeli kibbutz. The facts that kibbutz members have voluntarily chosen their lifestyle of cooperation and egalitarianism, the ease with which they could join the surrounding capitalist society and their disproportionate involvement in social and national causes suggest that if ever there was a society of individuals whose cooperativeness extends equally to members and non-members, the kibbutz is it. Nonetheless, our results indicate that kibbutz members display higher levels of cooperation when paired with anonymous kibbutz members than when paired with city residents. In fact, when paired with city residents, kibbutz members-observed levels of cooperation are identical to those of the city residents. Moreover, we show that self-selection rather than kibbutz socialization largely accounts for the extent to which kibbutz members are cooperative.cooperation, in-group-out-group bias, field experiment, self-selection, socialization, kibbutz

Does It Pay To Pray? Evaluating the Economic Return to Religious Ritual

Time-consuming and costly religious rituals pose a puzzle for economists committed to rational choice theories of human behavior. We propose that religious rituals promote in-group trust and cooperation that help to overcome collective-action problems. To test this hypothesis we design field experiments to measure the in-group cooperative behavior of members of religious and secular Israeli kibbutzim, communal societies for which mutual cooperation is a matter of survival. Our results show that religious males (the primary practitioners of collective religious ritual in Orthodox Judaism) are more cooperative than religious females, secular males and secular females. Moreover, the frequency with which religious males engage in collective religious rituals predicts well their degree of cooperative behavior. We use our results to understand differences in the return to religious observance in capitalist and developing economies.economics of religion, field experiment, religious ritual, cooperation, signaling, kibbutz

Stability of Groups with Costly Beliefs and Practices

Costly signaling theory has been employed to explain the persistence of costly displays in a wide array of species, including humans. Henrich (2009) builds on earlier signaling models to develop a cultural evolutionary model of costly displays. Significantly, Henrich's model shows that there can be a stable equilibrium for an entire population committed to costly displays, persisting alongside a no-cost stable equilibrium for the entire population. Here we generalize Henrich's result to the more realistic situation of a population peppered with subgroups committed to high-cost beliefs and practices. The investigative tool is an agent-based model in which agents have cognitive capacities similar to those presupposed in Henrich's population-level cultural evolutionary model, and agents perform similar fitness calculations. Unlike in Henrich's model, which has no group differentiation within the population, our model agents use fitness calculations to determine whether to join or leave high-cost groups. According to our model, high-cost groups achieve long-term stability within a larger population under a wide range of circumstances, a finding that extends Henrich's result in a more realistic direction. The most important emergent pathway to costly group stability is the simultaneous presence of high charisma and consistency of the group leader and high cost of the group. These findings have strategic implications both for leading groups committed to costly beliefs and practices and for controlling their size and influence within wider cultural settings.Costly Signaling, Credibility Enhancing Displays, Cultural Transmission, Religion, Charismatic Leader, Agent-Based Model

Do religious contexts elicit more trust and altruism? An experiment on Facebook

We design a decision-making scenario experiment on Facebook to measure subjects’ altruism and trust toward attendees of a religious service, a fitness class and a local music performance. Secular and religious subjects alike display significantly more altruism and trust toward the synagogue attendees than participants at the other two venues. By all measures of religiosity, even the most secular subjects behave more prosocially in the religious venue than in the comparable non-religious settings. We also find that secular subjects are just as altruistic toward synagogue and prayer group members as religious subjects are. These findings support recent theories that emphasize the pivotal role of religious context in arousing high levels of prosociality among those who are religious. Finally, our results offer startlingly little evidence for the widely documented religious-secular divide in Israel.religion, trust, altruism, religious context, religious-secular conflict

Cooperation and the In-Group-Out-Group Bias: A Field Test on Israeli Kibbutz Members and City Residents

The in-group-out-group bias is among the most well documented and widely observed phenomenon in the social sciences. Despite its role in hiring decisions and job discrimination, negotiations, and conflict and competition between groups, economists have heretofore ignored the in- group-out-group bias. We question the universality of the bias by designing field experiments to test whether it extends to the cooperative behavior of one of the most successful and best-known modern collective societies, the Israeli kibbutz. The facts that kibbutz members have voluntarily chosen their lifestyle of cooperation and egalitarianism, the ease with which they could join the surrounding capitalist society, their disproportionate involvement in social and national causes and their revealed willingness to sacrifice for the benefit of Israeli society as a whole suggest that if ever there was a society of individuals whose cooperativeness extends equally to members and non-members, the kibbutz is it. Nonetheless, the findings from our field experiments indicate that kibbutz members display higher levels of cooperation when paired with anonymous kibbutz members than when paired with city residents. In fact, when paired with city residents, kibbutz members’ observed levels of cooperation are identical to those displayed by the city residents. Moreover, we present evidence that kibbutz socialization actually damages the willingness of members to cooperate with one another.cooperation, in-group-out-group bias, field experiment, self- selection, socialization, kibbutz

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'

Social support, nutrition and health among women in rural Bangladesh: complex tradeoffs in allocare, kin proximity and support network size.

Malnutrition among women of reproductive age is a significant public health concern in low- and middle-income countries. Of particular concern are undernutrition from underweight and iron deficiency, along with overweight and obesity, all of which have negative health consequences for mothers and children. Accumulating evidence suggests that risk for poor nutritional outcomes may be mitigated by social support, yet how social support is measured varies tremendously and its effects likely vary by age, kinship and reproductive status. We examine the effects of different measures of social support on weight and iron nutrition among 677 randomly sampled women from rural Bangladesh. While we find that total support network size mitigates risk for underweight, other results point to a potential tradeoff in the effects of kin proximity, with nearby adult children associated with both lower risk for underweight and obesity and higher risk for iron deficiency and anaemia. Social support from kin may then enhance energy balance but not diet quality. Results also suggest that a woman's network of caregivers might reflect their greater need for help, as those who received more help with childcare and housework had worse iron nutrition. Overall, although some findings support the hypothesis that social support can be protective, others emphasize that social relationships often have neutral or negative effects, illustrating the kinds of tradeoffs expected from an evolutionary perspective. The complexities of these effects deserve attention in future work, particularly within public health, where what is defined as 'social support' is often assumed to be positive. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'

A practical guide to cross-cultural and multi-sited data collection in the biological and behavioural sciences.

Researchers in the biological and behavioural sciences are increasingly conducting collaborative, multi-sited projects to address how phenomena vary across ecologies. These types of projects, however, pose additional workflow challenges beyond those typically encountered in single-sited projects. Through specific attention to cross-cultural research projects, we highlight four key aspects of multi-sited projects that must be considered during the design phase to ensure success: (1) project and team management; (2) protocol and instrument development; (3) data management and documentation; and (4) equitable and collaborative practices. Our recommendations are supported by examples from our experiences collaborating on the Evolutionary Demography of Religion project, a mixed-methods project collecting data across five countries in collaboration with research partners in each host country. To existing discourse, we contribute new recommendations around team and project management, introduce practical recommendations for exploring the validity of instruments through qualitative techniques during piloting, highlight the importance of good documentation at all steps of the project, and demonstrate how data management workflows can be strengthened through open science practices. While this project was rooted in cross-cultural human behavioural ecology and evolutionary anthropology, lessons learned from this project are applicable to multi-sited research across the biological and behavioural sciences

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