"Paleo" skepticism

Here. Choice quote:

Some of our nostalgia for a simpler past is just the same old amnesia that every generation has about the good old days. The ancient Romans fretted about the young and their callous disregard for the hard-won wisdom of their elders. Several 16th- and 17th-century writers and philosophers famously idealized the Noble Savage, a being who lived in harmony with nature and did not destroy his surroundings. Now we worry about our kids as "digital natives," who grow up surrounded by electronics and can't settle their brains sufficiently to concentrate on walking the dog without simultaneously texting and listening to their iPods.

Another part of the feeling that the modern human is misplaced in urban society comes from the realization that people are still genetically close not only to the Romans and the 17th-century Europeans, but also to Neanderthals, to the ape ancestors Holland mentions, and to the small bands of early hominids who populated Africa hundreds of thousands of years ago. It is indeed during the blink of an eye, relatively speaking, that people settled down from nomadism to permanent settlements, developed agriculture, lived in towns and then cities, and acquired the ability to fly to the moon, create embryos in the lab, and store enormous amounts of information in a space the size of our handily opposable thumbs.

Given this whiplash-inducing rate of recent change, it's reasonable to conclude that we aren't suited to our modern lives, and that our health, our family lives, and perhaps our sanity would all be improved if we could live the way early humans did. Our bodies and minds evolved under a particular set of circumstances, the reasoning goes, and in changing those circumstances without allowing our bodies time to evolve in response, we have wreaked the havoc that is modern life.

In short, we have what the anthropologist Leslie Aiello, president of the renowned Wenner-Gren Foundation for Anthropological Research, called "paleofantasies." She was referring to stories about human evolution based on limited fossil evidence, but the term applies just as well to the idea that our modern lives are out of touch with the way human beings evolved and that we need to redress the imbalance. Newspaper articles, morning TV, dozens of books, and self-help advocates promoting slow-food or no-cook diets, barefoot running, sleeping with our infants, and other measures large and small claim that it would be more natural, and healthier, to live more like our ancestors. A corollary to this notion is that we are good at things we had to do back in the Pleistocene, like keeping an eye out for cheaters in our small groups, and bad at things we didn't, like negotiating with people we can't see and have never met.

[...]

To think of ourselves as misfits in our own time and of our own making flatly contradicts what we now understand about the way evolution works—namely, that rate matters. That evolution can be fast, slow, or in-between, and understanding what makes the difference is far more enlightening, and exciting, than holding our flabby modern selves up against a vision—accurate or not—of our well-muscled and harmoniously adapted ancestors.

The paleofantasy is a fantasy in part because it supposes that we humans, or at least our protohuman forebears, were at some point perfectly adapted to our environments. We apply this erroneous idea of evolution's producing the ideal mesh between organism and surroundings to other life forms, too, not just to people. We seem to have a vague idea that long long ago, when organisms were emerging from the primordial slime, they were rough-hewn approximations of their eventual shape, like toys hastily carved from wood, or an artist's first rendition of a portrait, with holes where the eyes and mouth eventually will be.

Then, the thinking goes, the animals were subject to the forces of nature. Those in the desert got better at resisting the sun, while those in the cold evolved fur or blubber or the ability to use fire. Once those traits had appeared and spread in the population, we had not a kind of sketch, but a fully realized organism, a fait accompli, with all of the lovely details executed, the anatomical t's crossed and i's dotted.

But of course that isn't true. Although we can admire a stick insect that seems to flawlessly imitate a leafy twig in every detail, down to the marks of faux bird droppings on its wings, or a sled dog with legs that can withstand subzero temperatures because of the exquisite heat exchange among its blood vessels, both are full of compromises, jury-rigged like all other organisms. The mantid has to resist disease as well as blend into its background; the dog must run and find food as well as stay warm. The pigment used to form those dark specks on the mantid is also useful in the insect immune system, and using it in one place means it can't be used in another. For the dog, having long legs for running can make it harder to keep the cold at bay, since more heat is lost from narrow limbs than from wider ones. These often conflicting needs mean automatic trade-offs in every system, so that each may be good enough but is rarely if ever perfect.

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Recognizing the continuity of evolution also makes clear the futility of selecting any particular time period for human harmony. Why would we be any more likely to feel out of sync than those who came before us? Did we really spend hundreds of thousands of years in stasis, perfectly adapted to our environments? When during the past did we attain this adaptation, and how did we know when to stop?

Just a warning not to follow any newfangled, trendy ideas too religiously, I think.

(With thanks to Lee on Twitter.)


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