Comment of the Day: I had always thought that the "male variability" hypothesis was really a "male skewed lower tail" hypothesis, and has nothing to say about the upper tail of males. It's the small Y-chromosome—the missing genes that make males overwhelmingly susceptible to color-blindness, hemophilia, the autism spectrum, may play a role in reduced life expectancy, and other things. But that male variability is greater because males are genetically weak says little or nothing about a possible genetic upper tail: Paul Reber: Patriarchy & Gender: "On Patriarchy & Gender... it's worth noting that a consequence of the Y-chromosome bottleneck 5000 years ago is that the 'fat tails' hypothesis that Pinker and Baumeister suckered Larry Summers with is obviously wrong. That is, the hypothesis that men exhibit genetically-dependent higher IQ variability, leading to more men on the upper tail of the distribution (and lower) which leads to over-representation in highly IQ-selective subsets such as professors at Harvard/MIT/etc....
...A collapse in diversity reduces variability, so any sex-linked aspect of intelligence/IQ would end up with substantially lower variability in men compared to woman after a more recent sex-specific genetic reduction (die off). The "evo psych" explanation never really made any sense anyway—Baumeister originally claimed men had to compete to mate which would somehow increase variability (it wouldn't, it would reduce variability and increase the mean). But it really doesn't make any sense given the existence of these genetic bottlenecks.
I always thought it was a shame that a really smart guy like Summers got tarnished by a bad idea like that. I use the example in my lab to teach my students of the dangers of working outside your own area—lack of domain knowledge makes you even more vulnerable to confirmation bias which you might catch in your area of expertise...
#commentoftheday
