I once found a book at the local library that was about the psychology of music, and how some music can lead us to the state of exstacy.

I found it a very interesting read until I got to a sentance in the first chapter that stated very definitively that, although human culture has existed for some 30,000 years, complex music has only been around for 3,000 years.

I put the book down in disgust, and never looked back. The truth is that we can not know how old music is, because unlike other aspects of human culture, it is possible to make music and leave absolutely no trace for future anthropologists to find.

Perhaps the first musical instrumments were only constructed 3,000 years ago, but people could have been clapping their hands and singing for millenia before that -- and we'd never know. A song doesn't leave any traces behind the way a firepit does.

And just because it's early doesn't necessarily mean it was simple -- for all we know, tribes Cro-magnon man could have been singing 7-part quodlibets...