According to the evolutionary psychologist Steve Stewart-Williams, almost everyone gets sex wrong. Traditionalists tend to exaggerate the natural differences between men and women. Progressives tend to minimise them, and to assume that nurture and socialisation play a decisive role. He wants to promote a more nuanced, scientifically rigorous public conversation about why and how men and women differ to guide better policymaking.
Some sex differences are relatively pronounced, he claims, such as whether you’re primarily attracted to men or women, upper body strength, height, the likelihood you’ll murder someone and occupational interests. Many, such as ability in maths, or conscientiousness, are much more modest. Such differences are best visualised as two overlapping bell curves. To illustrate this, consider height: the shortest humans are almost all women, the tallest are men, the average man is taller than the average woman, but there is considerable common ground. Knowing that someone is 5ft 8in won’t enable you to guess with any confidence whether they are a man or a woman, for instance.
A professor of psychology at the University of Nottingham Malaysia, Stewart-Williams writes in the careful, pedantic manner of someone who, quite reasonably, expects the reader to jump down his throat at any moment. One paper he wrote, which argued that the under-representation of women in Stem subjects was partly due to inherited differences in cognitive aptitudes, prompted a “minor online controversy” and led to him being reported to his university’s diversity, equity and inclusion administrators (it found that the complainants had misrepresented the paper). I tried, and it was effortful, to set aside my preconceptions and examine my kneejerk reactions while reading this, his second book, which tries to explain various physical, psychological and cognitive sex differences in terms of our evolutionary heritage.
Early on, Stewart-Williams offers a list of common biases in his field. Among them is the “gamma bias”: the tendency to minimise differences that paint men in a better light while highlighting those that do the opposite. One of his recent papers found that, when presented with fictitious studies showing that men draw better, lie less or are more intelligent, people rated them as lower in quality, more harmful and more worthy of being censored than fictitious studies showing that women possessed these positive traits. Another is the “delta bias”, an aversion to traditional sex differences and a preference for the reverse. Oddly, he doesn’t mention bias in the opposite direction, although the idea that women are the inferior sex and belong in the home has shaped much of human history and our inherited institutions.
To be clear, when Stewart-Williams argues that there are innate differences between men and women, he is quick to add that this doesn’t imply that one sex is better than the other, that we have a moral imperative to uphold or enforce sex differences, or that they are completely fixed. What he does believe is that if you give people freedom to choose their jobs and lifestyle, men and women tend to gravitate in different directions. Men tend to prefer working with things, women with people, for instance. Men are more motivated by status, women by relationships. Various studies add weight to Stewart-Williams’s claim by finding that many sex differences – from occupational preference to personality traits – are more pronounced in more gender-equal countries.
So what’s the other evidence that nature, rather than nurture, plays a bigger role than some assume? Stewart-Williams deploys the following arguments: sex differences have persisted historically and cross culturally, they mirror differences in other species, they manifest very early in childhood or become more pronounced during puberty, appear resistant to socialisation and seem to be influenced by prenatal hormonal exposure. They can also be explained in evolutionary terms: because men and women form close pair bonds, and men are more involved in child rearing than many other male animals, human sex differences are often much smaller than those that exist in the animal world. But if the driving force for evolution is the ability to successfully pass on one’s genes, this creates different incentives for men and women.
This book is filled with interesting, counterintuitive findings, studies you might want to discuss with a friend. But evolutionary psychology isn’t always the most useful lens. Stewart-Williams writes, for instance, that domestic violence is best understood as a manifestation of male aggression, rather than of patriarchy, as evidenced by the number of perpetrators who hold anti-patriarchal beliefs. This, he suggests, means that interventions aimed at teaching better self-control are more effective than targeting ideological convictions. That might hold true in gender-equal societies, but domestic and sexual violence is much higher in more patriarchal communities, where such behaviour is tolerated or even accepted. Clearly, an understanding of how socialisation and culture shapes sex differences matters immensely, too.
Stewart-Williams believes an underacknowledged contributor to women’s under-representation in Stem, or in leadership roles more generally, is innate differences in professional ambition and interests. Which I suppose is a more convenient response to the problem of unequal representation than trying to understand how offices, research institutions and leadership roles would be structured if women hadn’t been excluded for much of human history. (I note for example that men’s apparently weaker verbal abilities haven’t held them back in literature.) It’s important to understand the role that nature plays in making us who we are and shaping relations between the sexes – but it’s a small part of a big, complicated story.
