Neoteny and Two-way Sexual Selection in Human Evolution: Bibliographical Excerpts
|"But now let us return to the situation among humans. We have seen that Homo sapiens has a queer arrangement in which both sexes must compete for partners, and both, in turn, must choose. The stage is set for trait-runaway by sexual selection to take place in an unusual two way mode -- acting not only on males, but on females as well.
Human runaway sexual selection? At first glance we would seem too sensible a species for anything like that. We don't appear to have been saddled with burdensome exaggerations like antlers or bright tails. Or have we?
Consider the greatest exaggeration of them all... our powerful, out-sized brains. Not only do large infant craniums put human mothers in great stress while giving birth, the brains within strike some biologists as extremely perplexing. In their cups, philosophical anthropologists can sometimes be heard wondering why humans "overshot" the mental capacity we needed in order to become masters of the planet -- in other words, competent hunter-gatherers with stone tools and fire. That was enough to remove a lot of environmental stress, and should have led to a period of equilibrium. Instead, change only accelerated, until in short order we produced encephalization capable of conceiving mathematics, spacecraft design, and music more precise than any bird or whale could ever produce." (Brin, D (1995) Neoteny and Two-way Sexual Selection. web link.)