I recently discovered that others have thought about the evolution of music in this way also and therefore refer to music as “auditory cheesecake:” We evolved a huge appetite for sugar and fat when those nutrients were scarce in our diet but valuable to obtain, so needed high motivation (an affinity for the taste of these nutrients) to assure we identified sources and consumed them. That evolved taste for sugar and fat drives us to consume cheesecake, something that never existed in nature---except perhaps in the Garden of Eden (grin). So too might we consider our taste for music to have emerged from our capacity to process the sounds of language.
Some argue that we have to be taught to appreciate music in a way that is not required to appreciate cheesecake. However, from my experience this is not true---I always enjoyed hearing music, never really recalling a period of my life when there was not music of some sort occurring. Creating music does require learning and that ability varies.
There is plenty of reinforcement of our capacity to appreciate music. It is estimated that approximately 40% of the lyrics of popular music relate to sex in one way or another. Players of music seems to attract more mating attention (if not simply because of the pleasure of music in and of itself, it certainly is a gauge of the reproductive desirability of the player, requiring confidence before a group, coordination, dexterity, memory skills, physical fitness), something many of us admit is at least a fringe benefit, if not outright motivation for playing. Shakespeare said in one of his plays, “If music be the food of love, play on, give me excess of it.”
I’ve noted elsewhere that there seems to be a tribal reinforcement of group membership at work in music at times, e.g., in rap, military cadences, martial and ceremonial occasions. This would include the idea of the preservation of history by oral transmission in lyric poetry, taught from elder to young and passed on in each generation. The use of long distance instruments like trumpets and drums for communications in battle might have paved the way for Louis Armstrong and Buddy Rich. I do believe, though, that the earliest instruments were percussion (clapping hands, objects clacked together, drums of hide stretched over wood, etc.) and voice, followed by simple wind instruments, carved wood or ivory flutes (which have been dated to 35,000 to 43,000 years old).
I think we of the rock genre may be the modern troubadours, creating and performing songs of love and life, idealized and raw, but always with intensity.
See The Economist for an article sourcing some of the quotes and statistical references I used:
See also Wikipedia for a good article on prehistoric instruments:
And a great Wikipedia article on the cognitive neuroscience of music: