Thursday, January 10, 2019

Lesser Bird of Paradise

Photo of tail feathers by Kenji Aoki, from a pretty good Times piece on sexual selection and beauty.

I have always found the power of beauty over us to be deeply puzzling. I mean, a revulsion from ugliness or deformity makes evolutionary sense, because those things might signal other genetic problems, as does a generalized attraction to health and fitness. But our obsession with the right sort of nose or eye or breast goes far beyond this; and that's before we get to our mania for gold, silver, and gems, for bright fabrics, for flowers evolved to attract bees.

Our sense of beauty has come unmoored from the practical and stalked off on its own, claiming a huge part of our consciousness for its domain. Maybe this can be explained by sexual selection, genetic drift, or some such. But maybe not. Maybe it is a sign that our minds are expressions of a force for life that permeates our universe and drives us to wonder at creation, to be aware that we are part of the astonishing cosmos, and to be thrilled by that belonging.


Michael said...

The perception of beauty, especially, human beauty, has changed over time and is different from culture to culture. When Impressionists began to paint images of "drab" ordinary life - fish mongers, washer women, kitchen tables piled with fish and poultry and onions and cheese - our appreciation of what is beautiful was, I think, vastly expanded. It wasn't just the sumptuous dress of monarchs and courtiers, but most aspects of our lives.

G. Verloren said...

It's really very simple - evolution simply doesn't care about any random development that doesn't impact your ability to breed enough to lead to you being outcompeted.

Humans stopped evolving wholly naturally, and began evolving artificially a very long time ago when we supplanted natural apex predators through tool usage. Everything since then has followed a different set of rules than is normal in natural evolution. You simply can't examine human development past a certain point the same way you would examine the development of flowers or bees or anything else, because the factors became wildly skewed.

Each new technology improved our ability to survive in spite of negative inherited traits, and allowed those traits to continue to spread when in the natural course of things they likely would have died out.

For example, we have a distinct lack of protective hair or fur that ordinarily would tend to be crippling for an animal species, but we were able to compensate for that weakness by figuring out multiple different sophisticated technologies and combining them to allow us to fashion clothing out of plant and animal materials.

Think of the complexity involved in learning to fashion the tools and techniques necessary to hunt warm-pelted animals, as well as other different tools to skin them with and different techniques necessary to actually perform a successful skinning that produces a useable undamaged skin; developing the techniques to preserve that skin so it doesn't rot and fall apart or become a health hazard; and developing the techniques to fashion that preserved skin into complex shapes in order to create clothing. It's kind of astounding that we managed to figure all of that out, when you compare us to other highly intelligent creatures. And it gave us a remarkable technological edge that overwhelmingly counteracted our evolutionary weakness.

From an evolutionary standpoint, humans have absolutely no business surviving in cold environments, and yet we managed to both live and thrive in such places.

Our sense of beauty, along with our obsession for gold, et cetera, might very well be an evolutionary handicap that makes no sense in the context of natural selection. But we haven't existed in the context of natural selection for a very long time. Our numerous evolutionary handicaps mean nothing in a context where even our most basic forms of technological progress can outweight such handicaps almost completely.

Shadow said...

It gets tricky. Many adaptations/changes have no net evolutionary advantage or disadvantage until something in the environment changes, and then it does. So that obsession over a particular kind of nose could one day prove advantageous. You never know.

Skull size and birth canal diameter may be an example of co-evolution. There is precious additional space in that canal for a larger skull to pass. But this is also an example of where technology overrides. What at one time would have probably meant certain death for mother and child (eliminating the cause of the larger skull) is now a matter of a c-section, and the larger skull lives on. The reverse is also true: women with narrower birth canals now survive childbirth.

Having said that, I like that last sentence of yours best, John. It hints at the question "Why us"? It reminds us of another kind of beauty, one that's tied up in existence itself.

John said...

@G well yes we have culture, but so do other species; since some groups of chimps use tools and teach their children how, does that exempt them from natural selection?

We have faced very stringent selection over the past 200,000 years and our rate of evolution seems to have increased. The two biggest drivers may have been disease resistance and ability to eat the new foods produced by agriculture, such as milk and bread. The very rapid spread of adult lactose tolerance in Neolithic Europe implies that it conveyed a significant survival advance, more than 10%.

Events in the Bronze Age, in which certain warrior groups seem to have conquered widely and spread their genes across Europe, raise the question of whether their has been selection to be better at warfare, whatever genes that might be. Current estimates are that at least 60% of Neolithic Europeans have no modern descendants.

I would say that evolution has been different for humans, because of the large role of culture, but selective pressures have not disappeared.