Beauty is in the eye of the beholder.
That being said, the biases of "beholder's eye" are shaped by the environment in which said eye and it's ancestors reside in.
EVERYTHING can be seen as beautiful.
Some maniacs (due to some unfortunate mutation/upbringing) find scattered human intestines beautiful, but do you think this particular trait is favored by evolution? No. These kinds of people are constantly eradicated by our society (for a good reason) and so this particular view of beauty is not widely represented. Most people find guts of a dead human disgusting, and it's a more 'healthy' view that is more compatible with our civilization and it's well-being.
Let me illustrate another example.
Most of you who read this are probably afraid of, or disgusted by,
spiders. Even when you know the spider in question is clearly not poisonous, you still have innate fear of his small 8-legged body. It's mere presence unnerves you. Why don't you find it beautiful? Why don't you want to take it in your hand, and pet it? Answer lies in biology. For ancient humans, insects nearly ALWAYS meant trouble. Ants, mosquitoes, flies, bees, wasps, centipedes, and most of all - spiders. Spiders don't try to make their presence obvious, and a good many of them are/were poisonous. For millenia, they made their base in people's homes and often caused trouble. A genome which resulted in one NOT being afraid of spider is unfavorable, because those kinds of people were more likely to get bitten and die, thus people who love spiders are a clear minority even today.
The ways in which subtle things effect our group perception are not always as easy to see, of course.
Last edited by Odlov; Sep 6, 2009 at 07:57 AM.