Sustaining the potential for cooperation as female competitive strategy.

The lower female competitiveness often found in economic experiments presents a puzzle. If accumulating wealth and reaching high status affords women essential benefits for themselves and their children, why do women appear less competitive? By looking at behavioural strategies from a cooperative breeding perspective, we propose that women may have evolved an adaptation to strategically suppress competitiveness to elicit cooperation for the benefit of raising offspring. To support this idea, we review the literature that shows that women's behaviour is, in general, more reactive than men's to the social conditions of the different games. In particular, we focus on our experimental work where we show that women are not less competitive than men once the games evoke a parenting frame (by substituting cash with rewards that could benefit the participants' offspring), a gender-typical one (by using vouchers for prizes acceptable as domain of female interests), or include a prosocial option (by allowing winners to share some of the gains with losers). We conclude that, for women, nurturing the potential for cooperation intertwines with competitiveness to produce a complex, adaptive female social strategy. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.

Staying alive includes adaptations for catalyzing cooperation.

The target article interprets women's lower competitiveness than men's as evidence of adaptation to help women avoid physical conflicts and stay alive. This commentary advances the additional hypothesis that strategically suppressing competitiveness, thus signaling egalitarian intentions, could be an adaptation to catalyze cooperative behavior from males and females, turning natural competitors (other women) into allies and men into supportive partners.

Prosocial option increases women's entry into competition.

We provide evidence that women enter competitions at the same rate as men when the incentive for winning includes the option to share part of the rewards with the losers (i.e., when the incentive system is socially oriented). Using an experiment (with N = 238 subjects from three laboratories), we find that about 16% more men than women choose to compete in the standard tournament; this gender gap is eliminated in the socially oriented incentive treatment. While men's choice to compete remains unchanged, at around 52% in both conditions, women increase their entry rate from 35% in the standard tournament to 60% when the incentive includes a socially oriented option.

War increases religiosity.

Does the experience of war increase people's religiosity? Much evidence supports the idea that particular religious beliefs and ritual forms can galvanize social solidarity and motivate in-group cooperation, thus facilitating a wide range of cooperative behaviours including-but not limited to-peaceful resistance and collective aggression. However, little work has focused on whether violent conflict, in turn, might fuel greater religious participation. Here, we analyse survey data from 1,709 individuals in three post-conflict societies-Uganda, Sierra Leone and Tajikistan. The nature of these conflicts allows us to infer, and statistically verify, that individuals were quasirandomly afflicted with different intensities of war experience-thus potentially providing a natural experiment. We then show that those with greater exposure to these wars were more likely to participate in Christian or Muslim religious groups and rituals, even several years after the conflict. The results are robust to a wide range of control variables and statistical checks and hold even when we compare only individuals from the same communities, ethnic groups and religions.

Competing for the benefit of offspring eliminates the gender gap in competitiveness.

Recent advances have highlighted the evolutionary significance of female competition, with the sexes pursuing different competitive strategies and women reserving their most intense competitive behaviors for the benefit of offspring. Influential economic experiments using cash incentives, however, have found evidence suggesting that women have a lower desire to compete than men. We hypothesize that the estimated gender differences critically depend on how we elicit them, especially on the incentives used. We test this hypothesis through an experiment with adults in China (n = 358). Data show that, once the incentives are switched from monetary to child-benefitting, gender differences disappear. This result suggests that female competition can be just as intense as male competition given the right goals, indicating important implications for policies designed to promote gender equality.

War's enduring effects on the development of egalitarian motivations and in-group biases.

In suggesting that new nations often coalesce in the decades following war, historians have posed an important psychological question: Does the experience of war generate an enduring elevation in people's egalitarian motivations toward their in-group? We administered social-choice tasks to more than 1,000 children and adults differentially affected by wars in the Republic of Georgia and Sierra Leone. We found that greater exposure to war created a lasting increase in people's egalitarian motivations toward their in-group, but not their out-groups, during a developmental window starting in middle childhood (around 7 years of age) and ending in early adulthood (around 20 years of age). Outside this window, war had no measurable impact on social motivations in young children and had only muted effects on the motivations of older adults. These "war effects" are broadly consistent with predictions from evolutionary approaches that emphasize the importance of group cooperation in defending against external threats, though they also highlight key areas in need of greater theoretical development.