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.
Although it is often stated that man is the only primate that can talk, it is rarely noted that he is also the only one that can sing. Since singing is a simpler system than speech, with only pitch as a distinguishing feature, I suggest that he could sing long before he could talk and that singing was in fact a prerequisite to speech and hence language. Marler (1970a) has used the terms call and song to distinguish innate and learned signals in birds, and while the alarm or danger signal is usually a call, the territorial or mating signal is most frequently a song and is also more often uttered with non environmental stimulus. The learned nature of the territorial/mating song had resulted in more rapid evolution and in the evolution of bird dialects, which can be isolating mechanisms (Nottebohm 1970). Birds can also recognize individuals by vocal signals, and Thorpe (1968) has stated that some nesting birds can recognize their own family in a group of 2,000; this seems to imply an open semantic system. Haldane (1955) suggested that naming of persons and objects was the function of human vocalization that led to the development of language and symbolizing. Thus, it would seem that songs as group or personal names may have been the function of human vocalization that resulted in the opening of the call system. ... Much of primate vocalization occurs during territorial displays or encounters, and Rowell and Hinde (1962) do suggest that there may be rhesus dialects that are learned. (Livingstone, FB (1973) Did the australopithecines sing? Current Anthropology 14: 25)