I mentioned this persistent idea that male variability explains their “superior” intellectual abilities in my last post. There’s another example of the prevalence of this odd, unsupported idea going around — a twice-retracted paper that purports to find a mathematical basis for a sex difference.
The variability hypothesis generally states that the males of a species vary more widely in physical and physiological traits than the females. This theory is controversial because, since the beginning of the 20th century, it has mostly been used to refer to cognitive abilities—the purported greater frequency of both lower and higher extremes in intelligence among human males compared with females.
As Penn State University professor of psychology and women’s studies Stephanie Shields covered in her 1982 historical review (and in a follow-up 2016 review), scientists in the early 1900s asserted that there was a difference in the variability of mental traits between the sexes and attributed this difference to genetics, not considering environment and societal factors.
Again, I don’t find the idea credible at all. It’s entirely based on wishful thinking and a strange idea that nature is fair, and tries to support it with an unsupported belief that all biases must be symmetrically distributed. This paper was rejected for more specific, detailed problems, though.
The major flaw in the paper, according to Mark Kirkpatrick, a mathematical geneticist at the University of Texas at Austin who has published models of the evolution of mating preferences and selected traits, is that the rules of inheritance are not taken into account. “The paper’s conclusions are simply wrong,” he says. “The genes of the successful individuals in a population are transmitted to the offspring and [Hill’s] model does not have any equation that links up the genes of one generation with the genes of the next generation.”
Reed Cartwright, a computational evolutionary geneticist at Arizona State University, agrees. “My primary issue with Hill’s model is that it lacks any notion of genetics, and you cannot ignore genetics and make evolutionary conclusions,” Cartwright writes in an email to The Scientist. The model also ignores the role of gene-environment interactions, which are particularly important for complex traits, according to Cartwright. “Hill did not appreciate that if the difference between his two populations of males was due to environment and not genes, then his conclusions would be invalid.”
Yeah, if you invent an evolutionary model that handwaves away that awkward necessity of a mechanism of inheritance, you’re going to find that biologists are unimpressed. It reminds me of the time I attended a lecture by a mathematician/computer scientist on epidemiology, and she had tested her hypothesis with a simulation of viruses that she started by explaining that her model was the first one that used male and female viruses. Nope nope nope nope.