This is quite a nice talk by Daphna Joel on male brains and female brains — she’s making the point that there are no such things. There are differential responses by developing brains to the environment that lead to different structures…but because it is a property of interactions between sexual factors and the environment, it’s inappropriate to call the differences simply “male” or “female”.
These are the kinds of interactions that can lead to statistical similarities within a sex, and consistent statistical differences between sexes, which fits with the known data on biological differences in the brains of males and females. Many years ago, I was involved in some microscopical grunt work on analysis of cell sizes in the nucleus magnocellularis of mice — I’d get handed the prepped brain slices, and my job was to sit for hours tallying up diameters. What I’d see is individual variation — some mice had smaller average cells than others — and that there were slight differences on average between the sexes, with a huge amount of overlap. I was doing the counts blind, but I’d also make predictions from the cell size about the sex of the mouse. Alas, I was lousy at it. The differences were not sufficiently discrete to allow one to determine sex from size, although apparently some weak correlations emerged from the stats.
But that’s exactly what you’d expect from Joel’s model. It also means that there may be other factors which play a greater role in determining the brain differences than sex, but because the whole point of this kind of experiment is to minimize the number of environmental parameters that varied, we wouldn’t see them.
I agree with the conclusion of this video — it’s a mistake to assign the cause of brain differences to the sexual genetics of the brain when we can’t distinguish that from the influence of the experiences of that brain.