It's interesting how people seem to have just organically decided how long everything should be. Songs are a few minutes long, movies are a couple hours long, etc. What if society had evolved in such a way that, organically, we decided songs would be a half hour long? Is it based on societal sensibilities, or is it more biologically based (though of course the two are far from mutually exclusive)? I wonder if there was a society where humans were exactly the same, but the society itself was really different. Or a very similar society, but the humans were way smarter. Would songs and movies be the same length?