That is the Edge Annual Question for 2008. Here’s one reply:
Have Humans Stopped Evolving?
Ten years ago, I wrote:
For ninety-nine percent of human existence, people lived as foragers in small nomadic bands. Our brains are adapted to that long-vanished way of life, not to brand-new agricultural and industrial civilizations. They are not wired to cope with anonymous crowds, schooling, written language, government, police, courts, armies, modern medicine, formal social institutions, high technology, and other newcomers to the human experience.
Are we still evolving? Biologically, probably not much. Evolution has no momentum, so we will not turn into the creepy bloat-heads of science fiction. The modern human condition is not conducive to real evolution either. We infest the whole habitable and not-so-habitable earth, migrate at will, and zigzag from lifestyle to lifestyle. This makes us a nebulous, moving target for natural selection. If the species is evolving at all, it is happening too slowly and unpredictably for us to know the direction. (How the Mind Works)
Though I stand by a lot of those statements, I’ve had to question the overall assumption that human evolution pretty much stopped by the time of the agricultural revolution. When I wrote these passages, completion of the Human Genome Project was several years away, and so was the use of statistical techniques that test for signs of selection in the genome. Some of these searches for “Darwin’s Fingerprint,” as the technique has been called, have confirmed predictions I had made. For example, the modern version gene associated with language and speech has been under selection for several hundred thousand years, and has even been extracted from a Neanderthal bone, consistent with my hypothesis (with Paul Bloom) that language is a product of gradual natural selection. But the assumption of no-recent-human-evolution has not.
Much more here.