IQ of children in better-educated households is higher

http://www.eurekalert.org/pub_releases/2015-03/uov-ioc032415.php

Public Release: 24-Mar-2015
University of Virginia

Young adults who were raised in educated households develop higher cognitive ability than those who were brought up in less ideal environments, according to a new study conducted by researchers at Virginia Commonwealth University, the University of Virginia and Lund University in Sweden.

While the study does not refute previous findings that DNA impacts intelligence, it does prove that environmental influences play a significant role in cognitive ability as measured in early adulthood.

The study compared the cognitive ability - as measured by IQ - of 436 Swedish male siblings in which one member was reared by biological parents and the other by adoptive parents. The IQ of the adopted males, which was measured at ages 18-20, was 4.4 points higher than their nonadopted siblings.

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The adoptive parents in the study tended to be more educated and in better socioeconomic circumstances than the biological parents. In the study, parental education level was rated on a five-point scale; each additional unit of education by the rearing parents was associated with 1.71 more units of IQ. In the rare circumstances when the biological parents were more educated than the adoptive parents, the cognitive ability of the adopted-away offspring was lower than the one who was reared by the genetic parents.

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Previous studies have found that educated parents are more likely to talk at the dinner table, take their children to museums and read stories to their children at night.

"We're not denying that cognitive ability has important genetic components, but it is a naïve idea to say that it is only genes," Kendler said. "This is strong evidence that educated parents do something with their kid that makes them smarter and this is not a result of genetic factors."

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