Human evolution theory utilizing concepts of neoteny & female sexual selection
An etiology of neuropsychological disorders such as autism and dyslexia, and the origin of left handedness.
"But such paedomorphic trend could be explained if we could somehow show that it was part and parcel of the overall process of female choice for hunting skills. In fact, this is easier than it seems, because there are good reasons for believing that it would have been young, rather than mature, male hominids who first began to hunt. Experiments in which a colony of monkeys living near a beach were fed first with potatoes and then with rice left on the sand showed that it was a young member of the group who first discovered how to wash the food (as it happens, a female) and that the readiness to adopt this practice varied directly with age, younger individuals being more ready to take it up than older one. In the second place, it seems likely that younger, unmated males, probably associating in loose "all-male groups." would have been much better placed to undertake what must have been cooperative hunts than were older males encumbered with females and young who could not be left unguarded while their "owner" ran off chasing game. If homihid females with a taste for meat were prepared to reward younger, meat-giving hunters with matings, the reproductive success of such younger males would rise relative to that of older ones. This in itself could favor paedomorphosis by way of selection for youth, but it would also have set the scene for the other inevitable consequence of a meat-eating economy, in which greatly increased male parental investment could enable the gradual evolution of more retarded, paedomorphic infants. If we now ask what possible adaptive advantage such a general trend of paedomorphosis could have for human beings, the answer is obvious. It is simple that one, universal feature of paedomorphosis among vertebrates generally is that more immature forms tend to have larger brains relative to the rest of the body than more mature ones. Selection of young hunters by females would thereby have enabled selection for larger brains to come about as an inevitable, bu t unintended consequence." (Badcock, C. (1991) Evolution and Individual Behavior: An Introduction to Human Sociobiology. Oxford: Blackwell.pp. 186-7)
"For instance, one known effect of testosterone is to raise the resting metabolic rate of males by approximately 5 percent as compared to females. Effectively, this means that the male biochemical "engine" is running about one-twentieth faster all the time than is that of a woman, perhaps explaining why it wears out sooner." (Badcock, C. (1991) Evolution and Individual Behavior: An Introduction to Human Sociobiology Oxford: Blackwell. pp. 15)