Are men more competitive than women? Answering this question is complicated by the fact that men and women pursue differing goals and employ different competitive strategies. In this study, we examined reported reactions to married women and men with children who vary in specific resources. Results of the present study show that participant-observers from three nations reported that based on their experiences, the women that they knew would respond more negatively to a same-sex target with a valuable characteristic than would men in the same situation. In other words, women react more negatively to resource asymmetry among same-sex peers than men do, but not to resource asymmetry with other-sex peers. In fact, participant-observers report that women are actually less negative than men are towards other-sex peers. Thus, it is not the case that women are more distressed than men by resource asymmetry in general, rather this difference is only present with same-sex peers. These results suggest that the motivation for competition over resources is greater in 25–45-year-old married women with children than in their male counterparts. This extends findings from previous studies that have found few self-reported sex differences in tendencies to compete over mates28,29 or observational studies suggesting when payoffs are high women may compete more than men32,34 to include women and men who are married with children and know others who differ in their physical and social assets.

The implications of the results for understanding human society are important in that they indicate that while women and men employ different competitive strategies and often pursue different goals, women may have an even greater motivation to compete with same-sex peers than men. Thus, it seems reasonable that women may be more envious than men of same-sex peers who are better able to care for their children. This is particularly pertinent when resources involved in competition directly impact same-sex individuals’ and their offspring’s survival. In contrast male-male competition is more likely to impact only sporadic mating behaviors14,94. Further study of competition between mothers seems warranted, as others have recommended95,96. Importantly, these results also demonstrate that women are more positive than men with respect to resource differentials in the other sex. Thus, from a man’s perspective, women are less competitive with men than men are, which might provide a further explanation for the often-cited conclusion that women are the less competitive sex. Although the more negative reactions to resource asymmetry could be interpreted as a form of inequity aversion, this would not change their role as a motivator of competition97. Nonetheless, it would be unlikely that inequity aversion would apply more towards one sex than the other.

Both women and men reported that resource differentials in characteristics that benefitted men would produce more negative reactions compared to characteristics that benefitted women. Although we did not predict this, it is possible that male advantageous characteristics are more consistent with classic measures of group status such as dominance and prestige69 or socioeconomic status98, which have been shown to be desired by and benefit both women and men in terms of survival99. Further, these group status characteristics that may be associated more with men than women may also provoke more negative reactions because universally men hold higher status than women100. More research is needed that focuses on characteristics that may be particularly beneficial to women9.

Limitations of our study include that we had participants from only three countries, and other countries may produce different results. Likewise, all of our participant-observers had access to computers which clearly is not representative of simple societies. A more diverse and larger sample would further buttress the validity of the findings. We also did not include participants or targets who did not identify as women or men, so we cannot generalize these results to non-binary individuals.

Finally, in this study we used a very simple definition of resource differential: possession of a single positive characteristic that has been shown to be beneficial and hence should be desired by others. Although more complex definitions abound, we feel that this nonetheless captures the essential component of competitiveness. Thus, to the extent that intolerance of resource differentials is a major driver of competitiveness, one that is independent of whatever strategy might be employed to attain the resource, our results suggest that at the least between 25 and 45 years of age, married women with children may be more competitive than their male counterparts. While this conclusion requires confirmation using different measures, these results provide a further challenge to the validity of traditional sexual selection theory in which human males are considered more competitive than females.