It seems to be widely held that human body hair, being too thin to provide thermal insulation, is essentially functionless. It's my contention that it's probably multifunctional and that it's primary function is sensory. It may still have a role in thermal regulation for those who retain a lot of it and may have a role in carrying pheremones, perspiration as well as water away from the skin - with some impact on how well perspiration cools - however I want to focus specifically on hair's sensory function. I believe it's widely overlooked and I'm interested in how so many people, who live constantly with the sensory input these humble mechano-receptors provide, can fail to consider that function relevant to discussions on the evolution that led to our current (relative and variable) state of sparse hair cover, rather than fur covered, skin.
I think it is certainly vestigial, but there could be some functionality with it that nature has co-opted, like chaffing. I don't think the role is as pronounced as you theorize for the simple fact that certain humans have less hair than others. Are Asians, Africans and women then less adapted for sensory input than exceptionally hairy people, like many caucasians?
No doubt the evolutionary trend is that each successive generation is likely to be statistically less hairy than the one before it. If it served a vital and highly advantageous function it wouldn't be deleted from the gene pool and yet evidently it is.
Edited by Hyroglyphx, : No reason given.
"Men never do evil so completely and cheerfully as when they do it from mistaken conviction." — Blaise Pascal