Is men’s risk proneness still subject to sexual selection in modern environments?

– by Yohsuke Ohtsubo

Men are riskier than women, which is one of the most robust findings in psychology. When compared to women, men tend to report that they seek more risks in psychometric studies. In laboratory studies, men tend to show riskier behaviors, such as expanding a computerized balloon to the point of exploding to earn more money. Outside of the lab, men tend to drive faster (often causing more traffic accidents), engage more in extreme sports (e.g., cliff diving), and more often become involved in homicidal conflicts.

A common evolutionary explanation for this robust sex difference is sexual selection: Men’s risk proneness was selected for because it conferred upon men (but not women) fitness advantages in intrasexual competition and/or intersexual mate choice. However, sexual selection is associated with at least two “contradictory” predictions. Men in good conditions who are able to take risks (e.g., cliff diving) appeal to women by taking the risks. Thus, it is expected that risk-seeking men enjoy higher reproductive success (i.e., having more children). Alternatively, it is possible that men in poor conditions who have less to lose are more likely to take risks (e.g., crimes). In this case, risk-seeking men, due to their poor conditions, should have fewer children than men in better conditions, but they are still better off taking the risks because they would otherwise end up childless.

In our study, we were interested in whether risk-prone men tend to have more offspring than risk-averse men in modern environments (i.e., contemporary Japan and the US). However, we were aware of the possibility that we could end up with null results (i.e., no association between men’s risk proneness and reproductive success) because sexual selection operated in the past—our species’ ancestral environments. If modern environments are so much different from the ancestral environments, risk proneness may no longer confer any fitness advantage on men.

Given the possible evolutionary mismatch between the modern and ancestral environments, one may find this investigation itself a risky endeavor. However, as we acknowledged in the paper, we had preliminary evidence—our unpublished study involving middle-aged Japanese men showed that their retrospective reports of risk proneness were positively correlated with the number of children they had. That said, this investigation might have been risky because, partly due to the low reliability of recall data, the correlation was quite small (approximately 0.15).

Nevertheless, our curiosity outweighed the fear of null results. We collected data from 1,205 Japanese individuals (601 men and 604 women) aged 45 to 55 years old. Among other things, we measured their retrospective risk proneness during their 20s and 30s and the number of children they had. We assumed that the number of children reported by this age group comes very close to their lifetime reproductive success because less than 5% of fathers and only 0.19% of mothers of newborns in Japan are 45 years and older. We successfully replicated the small correlation for men. The retrospective risk proneness × number of children correlation was small but significant in men (0.123), while it was virtually zero in women. More importantly, the difference between men’s and women’s correlations (0.123 vs. 0.001) was significant (many thanks to an a priori power analysis!).

Encouraged by the Japanese results, we went ahead with another round of data collection in the US. This successfully replicated the Japanese results—men’s retrospective reports of risk proneness were significantly correlated with the number of children they had (0.143), while the same correlation for women was not significant (−0.002). And, again, the men’s correlation was significantly larger than the women’s!

In both countries, we used the domain general risk proneness score in the main analysis. Sample items included “I took risks regularly” and “I preferred to avoid risks” (reverse-coded item). However, for exploratory purposes, we also included domain-specific risk measures, which measured respondents’ willingness to take different types of risks: recreational risks (e.g., rock climbing, scuba diving), health risks (e.g., smoking), career risks (e.g., quitting a job without another to go), financial risks (e.g., gambling), safety risks (e.g., fast driving) and social risks (e.g., publicly challenging a rule or decision). Interestingly, only recreational and safety risk-taking consistently exhibited a similar pattern as the domain general risk proneness: men’s, but not women’s, recreational and safety risk scores were significantly correlated with reproductive success.

These results are generally consistent with the notion that men in good conditions take more risks, and their risk-proneness is associated with higher reproductive success. However, isn’t it possible that risk proneness is associated with higher reproductive success because only successful risk takers are involved in our data? Unsuccessful risk takers might have died in risky activities, such as rock climbing and cliff diving. The unmeasured cost of dying and the measured reproductive benefit may cancel each other out. Our unpublished follow-up data collected in Japan may have some clues on how to address this problem. It shows that men with good records in high school and college sports reported being more risk-prone during their school days than a control group of average achievers. Physically fit athletic men may engage in risky behaviors, such as extreme sports, while experiencing a lower risk of injury. Obviously, this issue needs more studies.

Despite certain limitations, the evidence from our research is useful for evolutionary psychologists to respond to a common criticism against evolutionary psychology. It is sometimes criticized as being a “just-so-story”—there is no direct evidence that this behavioral trait underwent sexual selection. That’s true. However, it is certainly more persuasive to say, “We know this is the case in modern environments, so perhaps it was like this in the past” than to say, “Perhaps it was like this in the past.” Although our research is admittedly a small first step, we think it still increased our knowledge about the role sexual selection has played (and seemingly continues to play) in men’s risk proneness.

Read the original article: Sakamoto, R., & Ohtsubo, Y. (2025). Men’s but not women’s risk proneness in early adulthood is associated with lifetime reproductive success: Evidence for sexual selection in modern environments. Evolution and Human Behavior, 46(1), 106654.