evolution of human hair

No, in fact, it doesn't. Each folicle grows for a period of time, goes dormant and the hair falls out. After a rest a new hair starts. The length depends on how fast it grows during the growth phase.I'm inclinded to think that the sexual selection idea might explain it if it actually gets to be an impediment. I'm not sure it does and it may also be that we have had some kind of control technology for a very long time. I wonder how long?

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Common sense isn't

I will continue talking to you even though you have made fun of my disfigurement. (and I'm considering taking it to the 'final solution' when the weather warms ). Skin Beauty - Not FoundTalks about the phases of hair growth (not exactly a primary source but will do for now).My point was that "hair" as a whole doesn't "keep growing". Each hair folicle is doing it's thing. I think some individuals have managed hair to the ground but I'll bet that there is a firm limit no matter how long they go without cutting (the same does not appear to be true of fingernails - and I've seen pictures of grotesque results).That doesn't mean your question about how this could be good (or not bad) is answered. Darned if I know.Do present day hunter gatherers cut their hair? (I'm thinking of, eg, the !Kung ).That site suggests 2 to 6 years is the time period of active growth. That may itself account for the differences in hair length.I just had another thought. (amazing 2 in a week! ). We do know that we lose a lot of energy through our busy little heads (about 25% ). Or conversly we risk getting heatstroke if too much heat is applied.Therefore it is important that we have hair to protect us. (I guess I am one of the "unfit" huh? ). Hair is subject to pretty severe conditions in the wild (not in modern socieity). If it didn't grow fast enough to maintain a covering we could be in trouble.

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Common sense isn't