It’s easy to think of history as a march of progress, with humans growing smarter and more capable over time. But if you think about how evolution really works, the march may be the opposite direction, Stanford biologist Gerald Crabtree argues in a new article in the journal Trends in Genetics. In other words, we may well be getting dumber.
Crabtree reasons that our intelligence and emotional stability would have
developed “in a world where every individual was exposed to nature’s raw selective mechanisms on a daily basis.” Before agriculture and urban society, human beings would have lived or died on their spatial reasoning skills: Learning to build shelters and tools took serious intelligence. By comparison, many contemporary activities that we think of as more intellectually taxing, like doing math problems, are actually computationally simple. That’s why your phone can beat you at chess, but even the most advanced robots are bad at washing dishes.
Now that evolutionary demands have slackened, so, perhaps, have our wits. Human intelligence must be mediated by many thousands of genes, he argues, and the more genes required, the more likely that some of them have mutated or been selected against over the millennia. The relatively stable societies we live in can make up for a lot of the resulting defects in thinking. “Community life would, I believe, tend to reduce the selective pressure placed on every individual, every day of their life,” he argues. “Indeed that is why I prefer to live in such a society.”
Crabtree’s essay is a speculation, not a finding – an experiment to prove it would be exceedingly challenging, given the potentially thousands of genes implicated, and the difficulties of accurately sampling the DNA of our long-dead ancestors. But if he’s right, evolution will join the growing list of things making us stupid, which already includes Google (via The Atlantic) and The Atlantic (via Los Angeles Review of Books).
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