The reason behind human appreciation of beauty is sometimes framed in evolutionary terms; we find a certain body type beautiful because it reflects good health, or we find a blossoming fruit tree beautiful because it can provide us with food. It is impossible to explain modern appreciation for art in simple evolutionary terms because it has been so heavily culturally constructed, any explanation for the evolutionary mechanism behind the appreciation of a Roy Lichtenstein work would be a stretch. But the roots of our contemporary aesthetic sensibilities are in this appreciation for natural beauty, which in turn was grounded in non-aesthetic value. But it seems to me like there are so many natural things that we find beautiful that would serve no purpose, or would actually be dangerous. The Sahara desert, poisonous plants or insects, or storms are certainly considered beautiful, but an early human would be ill-advised to seek them out for this reason. Are there other theories as to the origin of our...

It's very easy to speculate about the evolutionary origins of a trait, but often very difficult to defend such speculations with evidence. Natural selection is not the only engine of evolutionary change. So there's no particular reason to think that our capacity for aesthetic pleasure is an adaptation, rather than, say, a by-product of some other trait that is an adaptation, or a "spandrel" -- a feature that is the result of physical constraints on the structure or sub-structure of the organism. (Remember that in order for there to be natural selection, there has to be variation. If there's only one way that natural law permits a cognitive or affective structure to develop, then everyone would be the same.) There are also stochastic processes to consider: genetic drift, or founder effects (some desert-landscape lovers went and settled on an island, while all the desert-landscape haters suffered catastrophe on the mainland.) It's very difficult to figure out what kind of evidence or reasoning could...