Even the most cursory glance at life in traditional cultures is sufficient to demonstrate that music and dance are essential components of most social behaviours, everything from hunting and herding to story telling and playing; from washing and eating to praying and meditating; and from courting and marrying to healing and burying. Therefore the study of music origins is central to the evolutionary study of human cultural behaviour generally.
Music is yet another of the many ways in which human beings fulfil their creative impulse — objectifying their human essence through the ordering of aspects of the material world.
Despite the new wave of research, the precise origins of music remain opaque. Charles Darwin concluded that “as neither the enjoyment nor the capacity of producing musical notes are faculties of the least use to man in reference to his daily habits of life, they must be ranked amongst the most mysterious with which he is endowed.” Like language, music clearly draws upon diverse variables: the formation of the vocal tract and auditory system, hominid brain expansion, symbolic gesturing, the development of syntax, cultural transmission and many more evolutionary, cognitive and social aspects. Depending upon whom you ask, music is a form of sexual selection; a means of group bonding; a way for parents to communicate with their infants; or conversely a ‘spandrel’ drawing upon capacities that formed for other purposes, with no evolutionary value at all.
Trying to locate music in this or that part of the brain, or such and such an adaptive advantage, is probably futile. A Marxist reading of the evidence suggests that music arose as part of a complicated interaction of processes predicated upon the qualitative uniqueness of human consciousness. Music (and dance) cannot be reduced to a single function, and many of the processes crucial to its formation will have had no direct relationship to musicality at all.
Let us take one example. The physiology of music depends in part upon bipedalism, which allowed a lowering of the larynx and a greater control of sounds in the oral cavity. It also encouraged a 90-degree rotation of the labyrinthine capsule of the inner ear, which affected the morphology of the semi-circular canals responsible for balance and body coordination. In other words, bipedalism (as we touched on in the previous post) had implications for dance, breath control, and vocal expressiveness. Yet bipedalism is not an adaptation ‘for music’ but to life on the African savannah. It is not difficult to see from this that the totality of human music-making is dependent on a great web of evolutionary and cultural processes. Some of these processes will have been far more powerful determining forces than others, and establishing which were most important is the key to understanding music, but this does not mean the others can be ignored. So to explore the origins of music, we must also research the development of language, mind, and body through various scientific fields. This is the dialectical and materialist approach best placed to advance our understanding.
One of the most important characteristics of music is that it is primarily a social and collective activity. Attempts to explain it as a form of individual selection cannot account for why it has predominantly been created by groups. Adaptive theories only work when they are able to explain how music-making humans would have had an advantage over non-music-making ones — the only satisfactory account is that the former had advantages from stronger group cooperation, i.e. music as an adaptation can only work at the level of the social group. Therefore I find Steven Brown persuasive when he argues that “music making is not only about within-group cooperation, coordination, and cohesion, but it is principally about these things.” 
This does not mean of course that we cannot listen to music in solitude. But such behaviour is probably very unusual in the history of music, especially in its prehistory — and even listening in solitude requires, in usual Western practice, a set of musical equipment, such as MP3 players supplied with digital sound files, which has to be manufactured and therefore involve the solitary listener in a network of social labour.
Despite the uncertainty surrounding its origins, on one level music simply follows the same pattern as all the arts. We take the materials we find in nature and transform them through labour into a humanised object. Just as we use minerals to create pigments and make paintings, we take the naturally occurring phenomenon of sound and organise it, transform it and impose an order upon it to create a new ‘object’ in which we see ourselves objectified. Only humans do this. The study of gorillas beating their chests and animal mating calls, etc, is important and interesting, but social communication, group bonding, parent-infant interaction and so on are behaviours displayed by many animal species. Humans bring a particular qualitative ingredient to such activity which allows something new and unique to take off — it is in the extraordinary creativity of human consciousness that music really begins.
My own expectation is that music as we know it was probably a result of the cognitive leap that produced the Human Revolution. We may have had the capacity for making musical sounds for thousands of years, just as we had the capacity to make images on cave walls using tools long before we actually did so, but this could not become true music until our species underwent the enculturating process that made possible the flowering of art. Hence the absence of musical instruments until the Human Revolution was already underway — presumably there must have been other, cruder instruments at the outset around 60–40,000 years ago. How our basic musical capacity developed is still disputed, but whatever that process was, and whatever forms the earliest manifestations of musicality took, only with behaviourally modern, creative Homo sapiens could music flower.
 Wallin, Merker and Brown, ‘An Introduction to Evolutionary Musicology’ in The Origins of Music (2000).
 Charles Darwin, The Descent of Man (1871).
 Steven Brown, ‘The Musilanguage Model of Language Evolution’, from Wallin, Merker and Brown, op. cit.