Hey Jason Aldean: All Humans owe their Big Brains and Survival as a Species to Afro-Textured Hair

Ann Arbor (Informed Comment) – Afro-textured hair has been a frequent object of racist denigration. In April 2007 radio shock jock Don Imus got himself fired for referring to the Rutgers women’s basketball team as “nappy-headed ho’s.” Those formidable women, both scholars and athletes performing at a level Imus could never hope to, did not deserve the casual smear.

And it is hard to read Malcolm X’s account of “conking” his hair to straighten it in the 1940s and 1950s without cringing.

Controversies about race and appearance just won’t go away, as with the pulling of country music star Jason Aldean‘s “Try that in a Small Town,” which if it wasn’t explicitly racist at the least seemed to authorize violence by small town people (mostly white) against urban populations (heavily minorities).

In a recent article, however, Tina Lasisi, James W. Smallcombe, W. Larry Kenney, and George Havenith argued that Afro-textured hair was the evolutionary innovation that not only allowed upright human beings to survive heavy ultraviolet rays in tropical and sub-tropical Africa but allowed the human brain to double in size.

Scientists have found that the prefrontal cortex and the temporal and parietal regions of the brain in humans are unusually large compared with other primates, and that these regions are associated with higher cognition and the higher emotions.

It was the enlargement of these regions of the brain that made homo sapiens so different from the other apes, and if that development was permitted by Afro-textured hair, then we owe pretty much all we are in the way of civilization and science to it.

So the argument of Tina Lasisi and colleagues is that brain is sensitive to heat and as a complex organ has to find ways of cooling down when exposed to direct sunlight. The problem was exacerbated seven million years ago when some primates, such as Sahelanthropus tchadensis began standing up straight so that the sun beat down directly on their heads. The other primates don’t have Afro-textured hair, so it was a later adaptation.

Lasisi et al. write,

“We find evidence for a significant reduction in solar radiation influx to the scalp in the presence of hair. Maximal evaporative heat loss potential from the scalp is reduced by the presence of hair, but the amount of sweat required on the scalp to balance the incoming solar heat (i.e., zero heat gain) is reduced in the presence of hair. Particularly, we find that hair that is more tightly curled offers increased protection against heat gain from solar radiation.”

The poor bald people living at the equator take the full heat of the sun’s ray’s right on their noggins and have to sweat profusely to cool off their brains. People with Afro-textured hair are protected from the penetration of those sun rays down to their scalp, so their brains don’t get as hot and they don’t have to sweat as profusely. They observe, “Tightly curled human hair form does not lay flat on the scalp and therefore increases the distance between the surface of the hair and the surface of the scalp.” They just don’t get as much radiative heating on their scalp.

Remember that the problem of sun rays directly on top of the head was exacerbated by standing upright and that it made it more difficult to have a bigger brain, since that required more sweating and more water intake more often, militating against people being able to hunt or garden for long periods of time away from streams and lakes. Since predators are not as active in the midday heat, any evolutionary advance in humans that allowed them to hunt when it was sunny and hot out would have been an advantage.

We don’t know when Afro-textured hair first emerged. I should think geneticists might be able to clock it if they tried. Lasisi and colleagues admit two possibilities. One is that hominids’ brains increased in size, presenting a problem to which Afro-textured hair and its cooling effect came as a response. The other possibility is that the hair type emerged first, and that allowed the evolution of bigger brains.

Either way, this is a highly exciting and suggestive study. If its findings are further borne out, it shows that instead of being dismissive of Afro-textured hair, we should view it as a key breakthrough that led to human advancement and higher thought, as a gift of our ancient mother Eve.

In fact I have long wondered why people don’t go on pilgrimage to the Origins Museum in Johannesburg, South Africa. People go wild chasing their genealogy back a couple thousand years, but that was where it all started, 150,000 years or so ago. We’re all Africans, and black skin and Afro-textured hair was the default in modern humans until some moved out of Africa and had to adapt to low UV-ray environments where being too cold and getting too little sun and suffering from vitamin d deprivation made it advantageous to become pale with a long nose and straight hair.