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.
"Furthermore, drummers apparently know by intuition the most potent brain-stimulating rhythms. According to Neher, the predominant drumming rhythm used in a number of African dances as well as in Haitian voodoo dances is a fast 7 to 9 beats per second---and that happens to be about the same rhythm produced naturally by "brain waves" in the auditory cortex itself, groups of neurons charging and discharging in electrical unison. It seems that properly synchronized drumbeats drive the brain, force it into heightened activity. They work in phase with brain waves, amplifying them the way timed pushes impart more and more momentum to a swing, creating hallucinations and intense feelings of dissociation." (Pfeiffer JE (1982) The Creative Explosion. Harper & Row: New York p. 212)
"The prevalence of twilight-state thinking, our very susceptibility to the condition, argues for its [drum dance] evolutionary importance. In extreme cases it results in pathology, derangements and delusions, persisting hallucinations and fanaticisms. But it is also the driving force behind efforts to see things whole, to achieve a variety of syntheses from unified field theories in physics to blueprints for utopias in which people will live together in peace. These must have been an enormous selective premium on the twilight state during prehistoric times. If the pressures of the Upper Paleolithic demanded fervid belief and the following of leaders for survival's sake, then individuals endowed with such qualities, with a capacity to fall readily into trances, would out-produce more resistant individuals." (Pfeiffer JE (1982) The Creative Explosion. Harper & Row: New York p. 213)