Is your intelligence due to nature or nurture? That debate gets a little clearer as new research has determined intelligence, like other traits, is partly genetic.
Researchers from Harvard University and Union College analyzed dozens of genes using large data sets that included intelligence testing as well as genetic information.
The study was led by David I. Laibson, professor of economics at University, and Christopher F. Chabris, assistant professor of psychology at Union College, alongside a team of international researchers. Laibson, Chabris and colleagues, found, in almost all cases, the genes that were tested could not be linked to intelligence. Only one gene tested may have been associated with intelligence, but that association was minimal at best according to the researchers.
Although scientist understood intelligence can be inherited based on studies of twins, it wasn't until recently that technology has allowed scientists to directly analyze DNA seeking to find the gene that affects intelligence.
"We want to emphasize that we are not saying the people who did earlier research in this area were foolish or wrong," Chabris said. "They were using the best technology and information they had available. At the time, it was believed that individual genes would have a much larger effect- they were expecting to find genes that might each account for several IQ points." Researchers are a long way from identifying the genetic roots of intelligence. Additional research is needed to uncover the precise roles genes play on intelligence.
"As is the case with other traits, like height, there are probably thousands of genes and their variants that are associated with intelligence," Chabris explained. "And there may be other genetic effects beyond the single gene effects. There could be interactions among genes, or interactions between genes and the environment. Our results show that the way researchers have been looking for genes that may be related to intelligence-the candidate gene method-is fairly likely to result in false positives, so other methods should be used."
The study was published in the journal Psychological Science.