A New Study Supports Evolutionary Psychology’s Explanation For Why Men And Women Want Different Attributes In Partners

When it comes to the heated subject of differences between how men and women behave, debate in psychology has centered on mate preferences and general interests. The available research shows that when it comes to (heterosexual) mating preferences, men are relatively more interested in physical beauty, while women are relatively more interested in earning capacity. As for general interests, men are more interested in physical things, while women are more interested in people.

Even the staunchest evolutionary psychologists would acknowledge these are partially overlapping bell curves: There are plenty of men who are fascinated by other people, and plenty of women looking for physical beauty in a partner above all else. Yet the findings have been met with fierce resistance in some quarters. One of the more sophisticated rejoinders is known as social roles theory: The differences do exist, but they’re entirely or largely the result of gender roles imposed by society on individuals. However, a new study released as a preprint at PsyArXiv and involving participants from 36 countries has failed to replicate a key finding that’s previously been cited in support of social roles theory.

In its purest form social roles theory can be seen as sitting at the Nurture end of a Nature/Nurture spectrum, according to which sex differences in behaviour arise through cultural tradition. At the Nature end, on the other hand, are various evolutionary psychology accounts which posit that sex differences in behavior were carved into place by evolution. That is, since reproduction means such different things for men and women – men can pass along their genes at very little “cost,” while for women doing so entails gestation and childbirth at the very least – men and women have evolved different preferences for mates.

One of the most noteworthy studies published in support of social roles theory came out in American Psychologist in 1999. Alice H. Eagly and Wendy Wood reinterpreted data originally published by the evolutionary psychologist David Buss (showing average sex differences in mate preferences across cultures) and they reported that in countries with more egalitarian gender relations, the male-female differences were smaller. This suggested that gender equality gives women room to pursue their true romantic and sexual preferences, which aren’t all that far off from mens’.

However, for the new preprint,  Lingshan Zhang and Benedict Jones, and their colleagues at the University of Glasgow, have posed the exact same questions about mate preferences to a new sample (this one featuring 910 men and 2350 women from 36 countries, all of whom had ranked a number of traits in partners from most to least important, or rated those same traits numerically, or both) and their analysis casts serious doubt on the ability of social roles theory to explain these disparities.

The authors explain that in “contrast with Eagly and Wood (1999), who used aggregated data to calculate sex-difference scores at the country level, we used multilevel models to analyze the mate preferences for individual participants,” and they point to two studies which argue, in their words, that “the latter approach is preferable because it takes into account variability in preferences within each country.” (In all three studies – Buss; Eagly and Wood; and the new research – participants completed the same tasks, so it’s an apples-to-apples-to-apples comparison in that sense.)

Zhang and his team found, as per their abstract, that “Although women preferred mates with good earning capacity more than men did and men preferred physically attractive mates more than women did, we found little evidence that these sex differences were smaller in countries with greater gender equality,” as defined by United Nations statistics.

There was “one analysis [which] suggested that the sex difference in preferences for good earning capacity was smaller in countries with greater gender equality, [but] this effect was not significant when controlling for Galton’s problem or when correcting for multiple comparisons.” Galton’s problem is a statistical error that can occur when treating things as statistically independent that in fact aren’t – in this case, cultural practices in countries that are in close geographic proximity to one another.

In the end, after controlling for Galton’s problem, the researchers found just one mate characteristic that has been the subject of some evo-psych theorising – domestic skills like cooking and cleaning – for which the previously documented greater appeal to men than women effectively disappeared in more gender equal countries. Elsewhere, though, the differences were robust, both in the ranked- and rated-trait data, even controlling for gender equality.

In terms of how to interpret these new findings, Benedict Jones – co-author on the new preprint – clarified on Twitter that “the work doesn’t rule out social roles playing a role in mate preferences” and that “we don’t provide any direct evidence for evolutionary explanations of mate preferences and some of our recent work has challenged them. It’s complicated!”

However, the new analyses match up, at least partially, with those of an important 2010 article published by Richard Lippa, who asked a similar set of questions pertaining to sex differences in personality and interests. Summarising “two meta-analyses and three cross-cultural studies on gender differences in personality and interests,” Lippa found “small” to “moderate” sex differences with regard to Big Five personality traits, but “very large” ones with regard to the person–thing divide. “Gender differences in personality tend to be larger in gender-egalitarian societies than in gender-inegalitarian societies,” he found, “a finding that contradicts social role theory but is consistent with evolutionary, attributional, and social comparison theories. In contrast, gender differences in interests appear to be consistent across cultures and over time, a finding that suggests possible biologic influences.”

At the very least, Lippa’s study and the new one from Zhang and Jones et al make it harder for advocates of social roles theory to explain what’s going on. If sex differences in mate attraction were as simple as “Men are conditioned to seek out attractive women, and women to seek out high-earning men,” one would expect gender equality to have some effect on that dynamic. Nature and nurture surely intertwine and interact in myriad ways that humans may never fully disentangle, but for now these new results make it harder, as per Lippa, to rule out a strong role for “biologic influences.”

—Are sex differences in preferences for physical attractiveness and good earning capacity in potential mates smaller in countries with greater gender equality? [this study is a preprint meaning that it has not yet been peer reviewed and the final version may differ from the one that this report was based on]

Post written by Jesse Singal (@JesseSingal) for the BPS Research Digest. Jesse is a contributing writer at BPS Research Digest and New York Magazine, and he publishes his own newsletter featuring behavioral-science-talk. He is also working on a book about why shoddy behavioral-science claims sometimes go viral for Farrar, Straus and Giroux.