Endogenous testosterone promotes behaviours intended to enhance social dominance. However, recent research suggests that testosterone enhances strategic social behaviour rather than dominance seeking behaviour. This possibility has not been tested in a population whose members are known to vary in social status. Here, we explored the relationship between pre-existing social status and salivary testosterone level among members of a rugby team at a Japanese university, where a strong seniority norm maintains hierarchical relationships. Participants played a series of one-shot Ultimatum Games (UG) both as proposer and responder. Opponents were anonymised but of known seniority. We analysed participants’ acquiescence (how much more they offered beyond the lowest offer they would accept). The results showed that, among the most senior participants, higher testosterone was associated with lower acquiescence. Conversely, higher testosterone among the lower-status participants was associated with higher acquiescence. Our results suggest that testosterone may enhance socially dominant behaviour among high-status persons, but strategic submission to seniority among lower-status persons.

Impersonal cooperation among strangers enables societies to create valuable public goods, such as infrastructure, public services, and democracy. Several factors have been proposed to explain variation in impersonal cooperation across societies, referring to institutions (e.g., rule of law), religion (e.g., belief in God as a third-party punisher), cultural beliefs (e.g., trust) and values (e.g., collectivism), and ecology (e.g., relational mobility). We tested 17 preregistered hypotheses in a meta-analysis of 1,506 studies of impersonal cooperation in social dilemmas (e.g., the Public Goods Game) conducted across 70 societies (k = 2,271), where people make costly decisions to cooperate among strangers. After controlling for 10 study characteristics that can affect the outcome of studies, we found very little cross-societal variation in impersonal cooperation. Categorizing societies into cultural groups explained no variance in cooperation. Similarly, cultural, ancestral, and linguistic distance between societies explained little variance in cooperation. None of the cross-societal factors hypothesized to relate to impersonal cooperation explained variance in cooperation across societies. We replicated these conclusions when meta-analyzing 514 studies across 41 states and nine regions in the United States (k = 783). Thus, we observed that impersonal cooperation occurred in all societies—and to a similar degree across societies—suggesting that prior research may have overemphasized the magnitude of differences between modern societies in impersonal cooperation. We discuss the discrepancy between theory, past empirical research and the meta-analysis, address a limitation of experimental research on cooperation to study culture, and raise possible directions for future research.

Today, developing and maintaining sustainable societies is becoming a notable social concern, and studies on altruism and prosociality toward future generations are increasing in importance. Although altruistic behaviors toward future generations have previously been observed in some experimental situations, it remains unknown whether prosocial preferences toward future others are based on equality or joint outcome orientations. In the present research, we exploratorily investigated preferences regarding resource distribution by manipulating the time points (i.e., present/future) of the participants and their imaginary partners. The results indicate that prosocial preference toward future others was as strong as that toward present others and seemed to be based on a joint outcome prosocial preference. Notably, when participants and their partners were at different time points, participants preferred to leave resources for the persons in the future. The findings indicate that the type of altruistic preference toward future others may differ from that toward present others, which is mainly equality.

The Social Value Orientation (SVO) explains individual differences in cooperation attitudes. In this study, we examine whether the SVO affects the time taken, and amount of information gathered, when judging the trustworthiness of other people. Participants were able to choose a partner based on the past allocation patterns of candidates, mimicking how people are able to select with whom they cooperate in their social environments. We investigated the effect of the SVO on the method of gathering information on character and choosing a social exchange partner. The results revealed that participants with a prosocial (cooperative) orientation took less time to choose a partner, gathered less information, and tended to choose partners who behaved equally with everyone, compared to participants with an individualistic (selfish) orientation. Our findings suggest that people with a prosocial orientation prefer partners who treat everyone equally, regardless of the relationship, while people with an individualistic orientation deliberately seek out candidates who are likely to provide a relationship which is beneficial to themselves.

The purpose of this chapter is to review progress in our understanding of human behavior and decision-making relevant to future earth research agenda, and propose Decision Science as a hub of knowledge networks connecting disciplinary and interdisciplinary sciences with the practice of problem-solving. This review is composed of four sections. First, we describe the conceptual framework of “decision science for a sustainable society” and argue that evolutionary biology of the human nature is key to construct this framework. Second, we review how our group decision-making often fails due to various cognitive biases and argue that participatory approaches of co-design and co-production do not guarantee reasonable decision-making. Third, we review success stories of problem-solving in local communities and consider how we can connect those successes in local communities to successful national and global decision-making. Fourth, learning from both failures and successes, we argue that the adaptive learning of society is a process enabling us to transform our society toward a sustainable future. We review some positive global trends toward sustainability and consider the cognitive processes and behavioral mechanisms behind those trends that would provide clues for finding successful ways to transform our society.