"researchers have cautioned against oversimplifying this view. A meta-analytic review by McDaniel found that the correlation between Intelligence and in vivo brain size was larger for females (0.40) than for males (0.25).[14] The same study also found that the correlation between brain size and Intelligence differed for age within sex, with children showing smaller correlations.[14] Furthermore, the hypothesis has been put forward that the relationship between larger brain volumes and higher intelligence is facilitated not by the global increase of brain volume, but instead by the enlargement of selective parts of the brain associated with specific tasks.[9] For example, monolingual adolescents learning new words is displayed growth in gray matter density in bilateral posterior supramarginal gyri directly related to the number of words learned.[15] Similarly, learning to juggle increased grey matter volume in the occipito-temporal cortex for subjects who could not juggle previously,[16] indicating that brain volume is dependent on a large variety of things and not a perfect measure for intelligence."

https://en.wikipedia.org/wiki/Neuroscience_and_intelligence

Intelligence might have been extremely important when we were coming down from the trees millions of years ago but that says nothing about whether it has been the main selective pressure in the last 10 - 20 - 30,000 years. This is pure speculation.

Actually brains have been shrinking and we still seem to be just as intelligent - if not more so.

Neanderthals had larger brains than Homo sapiens. I have my doubts that the author believes they were more intelligent given his strong anthropocentric bias.

Wow... the author here accuses Stepehen Jay Gould (legendary evolutionary biologist) of denying that brains evolved. I think he might be misrepresenting him here.

A reasonable explanation for this is that slavery introduced a strong signal of artificial selection in African American populations. The weakest slaves died on the ships crossing the Atlantic, they died of disease and malnourishment. The strongest and tallest slaves were probably prized and given more opportunities to find sexual partners.

This is now known to be false. We shared a last common ancestor with gorillas about 11 million years ago and about half that timespan will separate us from chimpanzees.

Subjective

This is unsubstantiated nonsense. The average genetic distance between modern humans and neanderthals is far greater than the average genetic distance between East Africans and Central Asians. This would imply that the same is probably true of morphological differences.

This seems extremely subjective. I would proffer that while the author is probably adepot at distinguishing people from one another, he is probably not adept at distinguishing chimpanzees from one another.

This is unsubstantiated. Morphological differences could easily have become fixed in small populations due to drift.

10,000 years might leave a mark but it would be pretty much insignificant on evolutionary timescales. By far, the mark left would mostly be in regions of junk DNA which have no effect on phenotype.

Having said that there are small selective differences between populations that have recently diverged such as lactose tolerance and mutations that increase hemoglobin concentration

http://www.sciencemag.org/news/2014/07/tibetans-inherited-high-altitude-gene-ancient-human

What does that mean? "They do not do so evenly?" We can find people where 50% of their genome originates in Northwest Africa and the other 50% originates in Scandinavia. That would seem like a fairly even mix to me.

This is obvious nonsense and I'm not sure how the author can say this. Most people could point to the center of red and agree to label that red but they wouldn't be able to agree on where the boundaries occur.