In March 2017, a retired 73-year-old maths professor called Theodore (“Ted”) Hill was delighted when a paper of his was accepted at the Mathematical Intelligencer, an academic journal. The subject of the article, which he co-authored with another mathematician at Pennsylvania State University, was the “Variability Hypothesis” (VH) which states that there is more variation among the male sex when it comes to some traits than the female sex. Dr Hill had constructed a mathematical model to show how this might have come about via a process of natural selection.
The greater variability of males than females is something that generally holds true across the animal kingdom and was first noted by Charles Darwin in The Descent of Man (1871). But there’s one aspect of the hypothesis which has always made it controversial: it seems to apply to human intelligence. When you look at scores in intelligence tests, there are more men than women at either end of the statistical distribution curve, meaning more geniuses and more idiots. For instance, among those scoring in the top two per cent of America’s Armed Forces Qualification Test, men outnumber women by a ratio of almost 2:1. Men also outnumber women in America’s federal prisons — 13:1. It’s possible that this gender imbalance is entirely due to sociocultural factors, but when you put it alongside Darwin’s observations it begins to look at least partly hardwired.
Ted Hill must have known he was playing with fire by defending the VH, even if his model was intended to explain the greater variability phenomenon across a vast range of different species, not just homo sapiens. In 2005, Lawrence Summers, then the President of Harvard, got into trouble when he mentioned it as a possible explanation for why there aren’t more female professors in the maths and sciences at Ivy League colleges. This was at a conference on Diversifying the Science and Engineering Workforce and it wasn’t received well. Didn’t Summers realise that it was entirely to do with straight white men discriminating against women to perpetuate their privilege? One of the female professors in the audience walked out in disgust and it snowballed from there. Distinguished alumni withheld donations, Harvard’s Graduate School of Arts and Sciences passed a motion of no confidence in Summers and he was forced to apologise — over and over again — like a supplicant at a Chinese re-education camp. At one particularly fraught meeting, Nancy Hopkins, a biology professor at MIT, said that if she had to listen to him say another word she would be physically sick. In the end he had to resign. (To read more, click here.)