Evolution is rather stingy. It doesn’t tend to produce or maintain functions that have no purpose … and of course the only thing evolution is concerned with is producing babies who grow up to have more babies. Not even survival is mandated by evolution, as witness the species of insects (or, for that matter, salmon) who mate and then die.
I’ve read a couple of good books about the evolutionary basis for religious belief and behavior. But I don’t think I’ve ever read anything about the evolutionary basis for our sense of beauty. (Here’s a link — well worth watching: http://www.ted.com/talks/denis_dutton_a_darwinian_theory_of_beauty) The sense of beauty is nearly universal in our species. Without it, we wouldn’t be fully human. But how did it arise?
Religion seems to have several precursors. (I’ll leave you to read up on that topic on your own.) In the same way, I suspect, our sense of beauty springs from several sources. Mental tendencies have been reinforced in our species because they were useful — but as with the sex instinct, the actual behavior that results need not always have the intended effect. The behavior can become free-floating; it’s no longer moored to the actual need to make babies.
Very preliminarily (I’m just thinking out loud here), we can talk about the origins of the sense of beauty in the areas of fashion, function, fitness, and the free flow of information.
Fashion first. At some point in our evolutionary past, our ancestors started wearing clothing. We don’t know when or why or how that happened. Quite likely the first garments were uncured animal hides. Curing the hides, or at least hanging them from a branch to dry, would soon have followed. While leather would have provided some protection against thorns and small animal bites, and fur some warmth in cold weather, I suspect that the utilitarian benefits of clothing were not the original impetus in clothing’s invention. For one thing, in the parts of Africa where our ancestors evolved, it doesn’t often get too cold.
Many animals engage in displays of dominance (status within the band or herd) and fitness (the likelihood of producing viable babies). It seems to me that the original use of clothing was probably to enhance displays of dominance and fitness. And here’s the key point: Once animal hides are being used in that manner, the ability to judge the quality of the clothing becomes a useful social skill. A handsome, well-cured lion hide, complete with mane, that is being worn by the alpha male of your tribe is more impressive than the mangy, half-rotted, ripped-up hyena hide being worn by a lower-ranking male. If you can’t tell the difference, the likelihood of your passing on your genes to the next generation will be materially impaired.
Backing up a step, we also need the ability to judge fitness in the absence of ornamentation. Clear skin, body and facial symmetry, and the absence of disfigurements (warts and tumors) provides important information about the desirability of a potential mate. And by desirability, I mean the likelihood that the potential mate will produce viable offspring. Here again, the ability to form judgments about shape and texture is very useful.
Once our ancestors started making tools, another element was added to the mix. The beauty of a hand-ax lies not just in its smooth surface and its symmetrical form, but also (perhaps even more important) in its functionality — its fitness for its intended purpose. A hand-ax that’s smooth and symmetrical, but that’s too small or too large or has a dull edge, is not very functional. The ability to judge the fitness of an object for its intended purpose, be it a hand-ax, a throwing-stick, or a rope made of woven fibers, is a very useful skill. Things that are broken may once have been both useful and beautiful, but they’re not usually considered beautiful in their broken state.
The free flow or, or ready access to, information is also important. Consider a pond. If the water is clear, most of us would find it beautiful. If the water is muddy and murky, most of us would be a bit disgusted by it. Partly this is for reasons of hygiene. (Yes, you have an instinct to wash your hands.) But it’s also because if the water is clear, you can see what’s in the pond, be it fish (yum!) or an alligator (eek!). When the water is muddy, you get less information, and that’s not beautiful. The same could be said of a forest floor covered with debris. It’s more dangerous, because you can’t see what’s lurking. Therefore, by instinct, it’s not beautiful.
Of course, as aesthetes in the 21st century, we can find things like a jumbled forest floor or an old woman with warts beautiful. But that’s because the sense of beauty, once it exists, can be informed by our culture. It’s rather like the language instinct in that way. We don’t have an instinct to speak any particular language, so Chinese is not at all like Portuguese or Urdu. But we do have an instinct to learn, and produce, language.
I’ll probably have more to say about this topic later, after I’ve mulled it over for a while.