Genetics, not upbringing, main influencer in a child’s IQ, study says

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Can parents make their kids smarter? New research published in the journal Intelligence suggests they can’t influence intelligence— at least beyond their genetic contribution.

To answer the oft-asked question, professors at Florida State University, the University of Nebraska, West Illinois University, King Abdulaziz in Saudi Arabia, and Erasmus University in the Netherlands used an adoption-based research design.

The study authors drew participants from a representative sample of between 5,500-7,000 non-adopted youth and a sample of between 250-300 adopted children from the National Longitudinal Study of Adolescent Health.

Researchers first administered a Picture Vocabulary Test (PVT) to middle and high school students and then repeated the test when the participants were between the ages of 18 and 26. The PVT served as an IQ test in which participants had to identify photos of people, places and things. Researchers also analyzed their parents’ behaviors.

Researchers found that parental socialization had no detectable influence on children’s intelligence later in life.

“Previous research that has detected parenting-related behaviors affect intelligence is perhaps incorrect because it hasn’t taken into account genetic transmission,” study author Kevin Beaver, a criminology professor at FSU, said in a press release.

Some studies suggest that parents who interact with their kids over family dinners or by reading them bedtimes stories can boost their children’s IQ, while other research suggests that children’s IQs are only a product of their genetics.

Analyzing children who shared no DNA with their adoptive parents eliminated the possibility that parental socialization influenced a child’s intelligence.

“In previous research, it looks as though parenting is having an effect on child intelligence, but in reality the parents who are more intelligent are doing these things and it is masking the genetic transformation of intelligence to their children,” Beaver said.

Beaver noted that the findings don’t suggest that parents shouldn’t engage with their children, but rather that parents don’t have to go to extremes to influence their offspring.

“The way you parent a child is not going to have a detectable effect on their IQ as long as that parenting is within normal bounds,” Beaver said.

The study is published in the November-December 2014 issue of the journal Intelligence.