Since music draws on so many of the brain's faculties, it vouches for the health of the organ as a whole. And since music in ancient cultures seems often to have been linked with dancing, a good fitness indicator for the rest of the body, anyone who could sing and dance well was advertising the general excellence of their mental and physical genes to a potential mate.
Note: this applies to music performance, not music composition. Jimi Hendrix got laid like, well, a rock star, and if you're in a band you may be in with a chance. Sitting at your computer composing techno tunes is not a sign of Darwinian fitness, and unlikely to pull 'em in. As for DJing, the jury's still out.
Group singing, or chorusing, may have been an intermediate step in this process, he suggests. He has preliminary evidence that singing in church produces endorphins, a class of brain hormone thought to be important in social bonding, he said.
(I've heard it claimed in NLP circles that singing together puts one into a receptive state by the fact that one is, by necessity, breathing in synchronisation with everybody else in the church (including the celebrant of the service) and thus is more receptive to their beliefs; hence, it works as a sort of hypnotic persuasion technique.)
If you accept that there is a human nature (as opposed to the mind being a blank slate programmed by culture/patriarchy/capitalism/Sapir-Whorfian language), and it wasn't put there by God/benevolent aliens, the explanation that makes the most sense is that human nature was shaped by evolutionary pressures in the ancestral environment. I have yet to see an alternate theory that makes more sense, or indeed that doesn't primarily appeal to wishful thinking.
As for NLP, it seems to be more in the realm of alternative medicine than hard science, though bits of it seem to make empirical sense.
Yes, I would agree that environments have influenced us. However, it has often seemed to me that some evolutionary psychology is poorly reasoned, lacks evidence and can be a license for any old sorts of bollocks. This seems particularly so with some of the sexual stuff.
NLP seems to be a bit like Amway or that other one that other dubious group has public speaking focus. Lots of jargon words, take bits here and there from other psychology work, with two schools competing to be the dominant one who can make the most money.
Yes, there has been some bullshit expounded as "evolutionary psychology" (Kevin MacDonald's lunatical theory that Jews are biologically programmed to be evil, for example; he was one of the witnesses at the David Irving trial). However, that can be said about any area.
A lot of the problems people have with evolutionary psychology results from confusing "is" with "ought to be". Because evolutionary psychology shows that humans have a bias towards, say, greed or aggression or inequality doesn't mean that those things are inevitable or officially right, but rather that we have to be aware of these intrinsic biases and take them into account.
You're more likely to get more partners being in a band simply from the fact people have an excuse to come and talk to you, see you regularly, and be impressed by you enough to keep talking.
I've read that NLP is a big crock of shit. Evolutionary psychology also seems to be a field full of charlatans.