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.
"The need to hunt large animals may have been a main stimulus in the development not only of many physical features but also of social life and language. There is little evidence to go on but it is easy to imagine that the populations that survived contained genes ensuring co-operation among individuals, as well as efficient tool-making and tool-using. Hunting may well have been difficult for females and young and this would have led to the formation of stable social groups, with specialization of functions and sharing the results of the chase. This could be achieved by development of tendencies to co-operate, of which there are considerable signs already in monkeys and apes, though not usually for the purpose of getting food. Co-operation to drive, trap, and kill large prey such as antelopes or even elephants requires a reduction of competitive and aggressive behavior between individuals. In a sense this could be said to involve in man the continuation throughout life of the characteristic features found among juveniles of monkey and other animal communities. There are indeed several signs that the evolution of man had involved a process of 'juvenilization' or even 'foetalization'. Such a change, technically called neoteny (or paedomorphosis), has in fact occurred often in the course of the evolution of diverse animals (De Beer 1958). It is not difficult to understand how a delay in the rate of development of the reproductive system relative to the rest of the body could be produced by even a small genetic change; for instance , one affecting the pituitary gland. The result might be a striking alteration in the age structure of the population and hence in the psychology of its members." (Young, J.Z. (1971) An Introduction to the Study of Man: Clarendon Press, Oxford p. 478-9)