How culture leads to hairlessness

I recently wrote a summary article about why humans are hairless. The content is broadly similar to my much longer 2011 article on the topic, "Memes and the evolution of human hairlessness". Please refer to that article for references.

Why do humans differ from other great apes? They have stable and open-ended cross-generational cultural inheritance - in addition to the more common DNA-based inheritance. Apes have cumulative cultural evolution too, but with a low complexity ceiling. This cultural difference leads to most of the other differences, from walking and swimming to talking, large brains and ultrasociality. How does culture affect hairlessness? In three types of ways:

• It allows humans to compensate for the disadvantages of missing a genetic adaptation with cultural adaptations. Bedding, housing, clothing, baby slings, and so on all become possible with cultural inheritance.

• Another way is by changing the intensity of selection pressures that favor hairlessness. One pathway is via ultrasociality and parasites. Larger group sizes with more social contact (which are facilitated by culture) may lead to more opportuities for parasites to spread, and may also result in more grooming opportunities. Bathing, wading and swimming may also affect hairlessness. As might the odd and no doubt culturally transmitted human habit of using pack hunting and long distance running to exhaust their prey.

• Lastly, hairlessness is a sexually dimorphic trait. It is associated with neoteny, which seems to have been favored as a mechanism for other reasons during human evolution. Neotoney facilitates our culturally-magnified large brain fitting through the human pelvis - among other things. At some stage in human evolution, youthful, hairless females had benefits in terms of sexual attractiveness. Hairy women were not so favoured. Being visibly free from ectoparasites abd other disease may have been part of it. The effects of female hairiness may have spread over to men too, since men and women share many genes. Sexual selection seems to have been be a factor in promoting human hairlessness.