In the past century, humans have landed a man on the moon, sequenced the genome, and created the Internet — but, surprisingly, we may be slowly evolving to be less intelligent than our ancestors.
That's because a series of mutations affecting the estimated 5,000 genes controlling human intellect have crept into our DNA, says Gerald Crabtree, a geneticist at Stanford University, whose findings were published in the journal Trends in Genetics. And modern society allows people to focus on becoming an expert in one thing — we no longer need a wide breadth of knowledge or even cognitive ability in order to thrive.
"I would wager that if an average citizen from Athens of 1000 BC were to suddenly appear among us, he or she would be among the brightest and most intellectually alive of our colleagues and companies, with a good memory, a broad range of ideas, and a clear-sighted view of important issues," Crabtree writes.
"Intelligence doesn't play as significant a selection in our present, supportive wonderful society," he says. Humans no longer (or rarely) die because they were unable to outwit a predator. Humans were much more likely to die due to "lack of judgment" thousands of years ago, he says.
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