Submitted for the workshop Logic and Music at the 6th World Congress on Universal Logic, June 21-26, Vichy, France.
Musical Activity as the Basis for the Evolution of Joint Intentionality and Nonlinear Grammar
The perfection of singing, drumming and dancing, performed in unison, may have driven our evolutionary ancestors to develop joint intentionality, nonlinear grammar, and additional traits which distinguish us, as humans, from the other great apes.
As Tomasello has persuasively argued, what seems to distinguish us from the great apes is our joint intentionality. Chimpanzees play different roles in hunting a monkey. But each will abandon the team if distracted by something more rewarding. One-year-old human infants, on the other hand, persist until everyone on their team receives their reward. Our ability to be an ad hoc "we" makes us human.
Humans typically manifest this solidarity physically through body language. We exhibit a "sixth sense" by which we unconsciously orient ourselves towards those present around us. We synchronize all of our movements. When we slow down a video of people, they seem to be dancing. Other great apes may lack this joint synchronicity.
Musical activity could have fostered such joint synchronicity. It may have started with identical twins. Rhythmic unison - singing, drumming and dancing together - may have attracted mates, and engendered a virtuous cycle of rapid evolutionary change. This would have fostered that "sixth sense" but also improved vocal chord control. For the group, musical activity could have heightened the sense of "we" before and after a shared activity, such as a hunt. Work songs fostered a sense of shared work. As the repertoire of songs grew, they could influence language.
In linguistics, Jackendoff has noted that syntax must have arisen after a protolanguage with a linear grammar which was quite robust. Such a linear grammar is used by sailors speaking pidgin; second language users who never develop fluency; people with certain brain injuries; deaf children who develop their own gestures; but also the great apes. It consists of strings of words for which there are no rules. Word order is simply determined pragmatically in context.
Joint musical activity demands a perfection of all and at all times. It thus legislates rules. Sounds or words must be annunciated exactly. Rituals develop. Words and concepts become categorized, as Levi-Strauss observed. People develop a sense of right or wrong, in-tune or out-of-tune, grammatical or ungrammatical. Rules must be followed in creating new words. Syntax arises as rules which may not be broken, and is distinct from pragmatic constraints.
Language arises from pragmatic activity. Nonlinear grammar arises with the division of labor such that we can perform a task that we do not completely understand, as when using a new word, or playing our own part in a greater musical whole. This fosters our ability to hear what others are saying as well as what we ourselves are thinking. Whereas perhaps other apes can only think one perspective at a time. Thus they can answer questions but they never ask them. Musical activity teaches us to be "I" and "you" and "they" and "we", in parallel.