Wednesday, August 09, 2017


WB and Lee* point out this nice commentary by Scott Alexander on male and female differences. The subject is an article by Adam Grant claiming that Differences Between Men And Women Are Vastly Exaggerated.


Across 128 domains of the mind and behavior, “78% of gender differences are small or close to zero.” A recent addition to that list is leadership, where men feel more confident but women are rated as more competent.


Suppose I wanted to convince you that men and women had physically identical bodies. I run studies on things like number of arms, number of kidneys, size of the pancreas, caliber of the aorta, whether the brain is in the head or the chest, et cetera. 90% of these come back identical – in fact, the only ones that don’t are a few outliers like “breast size” or “number of penises”. I conclude that men and women are mostly physically similar. I can even make a statistic like “men and women are physically the same in 78% of traits”.

Then I go back to the person who says women have larger breasts and men are more likely to have penises, and I say “Ha, actually studies prove men and women are mostly physically identical! I sure showed you, you sexist!”

I worry that Hyde’s analysis plays the same trick. She does a wonderful job finding that men and women have minimal differences in eg “likelihood of smiling when not being observed”, “interpersonal leadership style”, et cetera. But if you ask the man on the street “Are men and women different?”, he’s likely to say something like “Yeah, men are more aggressive and women are more sensitive”. And in fact, Hyde found that men were indeed definitely more aggressive, and women indeed definitely more sensitive. But throw in a hundred other effects nobody cares about like “likelihood of smiling when not observed”, and you can report that “78% of gender differences are small or zero”.

Hyde found moderate or large gender differences in (and here I’m paraphrasing very scientific-sounding constructs into more understandable terms) aggressiveness, horniness, language abilities, mechanical abilities, visuospatial skills, mechanical ability, tendermindness, assertiveness, comfort with body, various physical abilities, and computer skills.

Perhaps some peeople might think that finding moderate-to-large-differences in mechanical abilities, computer skills, etc supports the idea that gender differences might play a role in gender balance in the tech industry. But because Hyde’s meta-analysis drowns all of this out with stuff about smiling-when-not-observed, Grant is able to make it sound like Hyde proves his point.

It’s actually worse than this, because Grant misreports the study findings in various ways [EDIT: Or possibly not, see here]. For example, he states that the sex differences in physical aggression and physical strength are “large”. The study very specifically says the opposite of this. Its three different numbers for physical aggression (from three different studies) are 0.4, 0.59, and 0.6, and it sets a cutoff for “large” effects at 0.66 or more.

On the other hand, Grant fails to report an effect that actually is large: mechanical reasoning ability (in the paper as Feingold 1998 DAT mechanical reasoning). There is a large gender difference on this, d = 0.76.

And although Hyde doesn’t look into it in her meta-analysis, other meta-analyses like this one find a large effect size (d = 1.18) for thing-oriented vs. people-oriented interest, the very claim that the argument that Grant is trying to argue against centers around.

Lumped statistics can be very deceptive. Our cells look and operate very similarly to those of flatworms and fungi.

It's a long post, and I only quoted a bit. I recommend both it and Grant's response.

*Might be a good name for an alt-country band.