Women are the proto R-selected human species. Women use white matter to navigate social systems. Men are the proto k-selected human species. They use gray matter to navigate the natural world.
Now then, on to random blather.
Females and males maintain unique brain characteristics throughout life. Male brains, for instance, are about 10% larger than female brains. But bigger doesn’t necessarily mean smarter.
The confound here is because IQ up to 130 is dependent almost entirely on white matter production (scales up geometrically with surface area and cortical folding). Purely visual intelligence like the draw-a-man test is very well-predicted by volume (whereas manipulations require a combination).
Disparities in how certain brain substances are distributed may be more revealing. Notably, male brains contain about 6.5 times more gray matter — sometimes called ‘thinking matter” — than women. Female brains have more than 9.5 times as much white matter, the stuff that connects various parts of the brain, than male brains. That’s not all. “The frontal area of the cortex and the temporal area of the cortex are more precisely organized in women, and are bigger in volume,” Geary tells WebMD. This difference in form may explain a lasting functional advantage that females seem to have over males: dominant language skills.
White matter = verbal IQ. But white matter alone will only get you that far and no further, and the absence of gray matter (scales up exponentially with volume) will produce a “clever silly”. On the other hand, a person with gray matter and no white matter will be unable to access the gray matter properly and will score poorly on IQ tests. Ex. Smart rednecks at the high end and autistics on the low end. A proper genius must have lots of both.
How Males and Females Use Mental Skills
Geary suggests that women use language skills to their advantage. “Females use language more when they compete. They gossip, manipulate information,” he says. Geary suggests that this behavior, referred to as relational aggression, may have given females a survival advantage long ago. “If the ability to use language to organize relationships was of benefit during evolutionary history, and used more frequently by women, we would expect language differences to become exaggerated,” he tells WebMD.
Men who have abnormal amounts of white matter (Vox Day and Koanic, for instance) tend to be “Machiavellian”, but the fact of the matter is that they are probably less so by disposition than the average woman. The only reason they tend to be more successful than women in this regard is the overwhelming force of high testosterone.
As an interesting aside, the overabundance of white matter actually creates visuospatial retardation. This can be explained by an offhand observation in the neuroscience video (skip to ). If the control-freak nature of the will is shut off then most people become better at drawing. That is, the white matter actually over-rides the basic talents of the gray matter, which is to perceive and manipulate visualizations of the environment. More white matter means more micromanaging by the ego, and more visuospatial retardation.
I think the white matter thing also explains the phenomenon of high-IQ narcissists that I call megalomaniacs. Basically, these guys have an overbearing surfeit of willpower (chemical energy available to the white matter network), which adds up to excessive self-consciousness and therefore larger-than-life egos.