Stanford developmental biologist Gerald Crabtree argues that human intelligence has been deteriorating since our ancestors abandoned their nomadic ways and settled into a safer, sedentary lifestyle.
"A hunter-gatherer who did not correctly conceive a solution to providing food or shelter probably died, along with his/her progeny, whereas a modern Wall Street executive that made a similar conceptual mistake would receive a substantial bonus and be a more attractive mate. Clearly, extreme selection is a thing of the past," explains the professor's team in a recent study.
If correct, it would appear that the very same evolutionary forces that elevated our brain's capacity for abstract thought are now working to limit its evolutionary potential.
Crabtree states, "It is very likely that within 3000 years we have all sustained two or more mutations harmful to our intellectual or emotional stability."
He adds, "The development of our intellectual abilities and the optimization of thousands of intelligence genes probably occurred in relatively non-verbal, dispersed groups of peoples [living] before our ancestors emerged from Africa."
The University of Warwick's Thomas Hills, a psychologist unrelated to the research, asserts that while we losing our ability to effectively survive in the wild, our intelligence is moving forward in new directions that Crabtree does not recognize.
"You don't get Stephen Hawking 200,000 years ago. He just doesn't exist. But now we have people of his intellectual capacity doing things and making insights that we would never have achieved in our environment of evolutionary adaptation," Hill said to LiveScience.
Even if Crabtree is correct, he does not believes that all is lost. In the future, we may be able to "magically correct any mutation that has occurred in all cells of any organism at any developmental stage. Thus, the brutish process of natural selection will be unnecessary."
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