My Quillette review of Steve Stewart-Williams’s new book on sex differences in humans

Steve Stewart-Williams has recently published an informative and readable new book (link at the screenshot just below), and my 4000-word review of it for Quillette just appeared (click second screenshot below for the review):

As I implied, my review is laudatory, with only a few (really one) reservations, which is minor. It’s not a “page turner”, either, which means that you have to retain some fairly sophisticated biology in your head as you read it—stuff about sexual selection. This will discourage those people who still actually read books (they will also find my review long, as I have to explain the thesis, the nature of sexual selection, and the data).

As I say in my review, Steve’s point is to suss out the causes of human sex differences “above the neck” (i.e., in aptitudes, behaviors and preferences). The differences could in principle be due to biases, socialization, or genes (“innate” stuff), though males and females have almost exactly the same set of genes save for the crucial SRY “sex-determining gene” on the Y chromosome.  Insofar as sex differences in physiology, behavior, preferences, and morphologyare genetic, they must be due almost entirely to differences in expression of a nearly identical set of genes—expression differences part of a developmental cascade kicked off by whether the crucial SRY gene is expressed.

I’m allowed to quote just three paragraphs here, so here are three I selected:

But the questions [Larry Summers] raised remain, and there are several. First, are there real differences in behaviour and aptitude between the sexes? Although the sexes have obvious physical differences, many “blank-slaters” think that things are roughly equal from the neck up, with no average sex differences in thoughts, preferences, or behaviours. Second, if there are such differences, where did they come from? Are they due to sociocultural influences, like patriarchy and socialisation, or are they largely innate—that is, based on genes? Finally, if some sex differences are inherited, did the genes involved arise by natural selection in our ancestors, with the differences enhancing reproduction? Answering “no” to all of these questions makes you a full-blown blank-slater, while answering “yes” makes you a genetic determinist—perhaps the most damaging label that can be stuck on a liberal thinker.

In A Billion Years of Sex Differences, Steve Stewart-Williams argues that it’s time to engage these questions with data. Summarising existing research, he comes down closer to genetic determinism than to blank-slatism. That is, he sees significant sex differences in thinking, behaviour, and preferences as having a substantial genetic basis, but he recognises too a role for sociocultural influences.

. . . . All of this evidence for innateness—persistence despite discouragement, consistency among cultures and over the ages, developmental trajectories, parallels with other species, and the gender equality paradox—is explained most parsimoniously not by a purely sociocultural hypothesis, but by positing some genetic basis for sex differences. No line of evidence is conclusive by itself, but their “consilience”, the convergence of diverse lines of investigation on innate explanations, is convincing. Stewart-Williams hastens to add that we often can’t rule out some sociocultural basis for large sex differences, but as a whole the pure blank-slate idea just doesn’t hold up. We already knew that for things like height and hairiness; now we also know it for what’s produced by our brains.

Throughout the book, the assumption is, reasonably, that there are just two sexes, and Stewart-Williams doesn’t deal with the faux controversy about the number of biological sexes, nor does he need to. Read my review, if you can, and if you think you’d like the book, get it. Everyone interested in the nature and source of differences in behavior and mentation between the sexes should, I think, be interested in it.