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 primary reason for the lack of size change in the skull and face of the pygmies is probably related to a combination of early growth priority and these structures (especially reflected in those measurements incorporating the skull base: basion-nasion and basion-prosthion), plus the fact that in humans overall skull size is negatively allometric to body size and weight. This is even true of the facial skeleton in humans, so that a marked change in body weight may result in little or no alteration in facial size. Evidence to this effect can be seen in the pubertal growth spurt, during which males become significantly larger than females in height and weight, but metric aspects of facial size are still largely indistinguishable (Keen, 1950)." ( Shea, B.T. & Gomez, A.M. (1988) Tooth scaling and evolutionary dwarfism: an investigation of allometry in human pygmies. American Journal of Physical Anthropology 77 (1): pp. 129)