The truth about intelligence: What makes someone smarter than others? | AI
Our search for genes associated with brainpower is starting to bear fruit, but isn’t the whole story. Your IQ is influenced by many subtle factors
One reason people may find discussing intelligence uncomfortable is the belief that it is something you are born with and so you can do nothing to influence it. This undercuts social equality, and feeds into the link between intelligence testing and eugenics, which still looms large for many.
However, there is no escaping the fact that intelligence is inherited to some degree. Researchers found that the IQ of children adopted at birth bore little correlation with that of their adoptive parents, but strongly correlated with that of their biological parents. What’s more, this association became stronger as the children grew older.
“That’s counter-intuitive for most people,” says Robert Plomin at King’s College London, who led the study. “They think as you go through life, the slings and arrows of outrageous fortune build up and environmental differences become cumulatively more important, because they think that genes only influence what happens at the moment of conception.” That’s not true, of course.
In fact, hundreds of studies all point in the same direction. “About 50 per cent of the difference in intelligence between people is due to genetics,” he says.
But genes are not destiny
For many years, the search for specific intelligence genes proved unfruitful. Recently, however, genetic studies have grown big and powerful enough to identify at least some of the genetic underpinnings of IQ. Although each gene associated with intelligence has only a minuscule effect in isolation, …