A child’s environment is the critical tool that allows his or her genetic IQ to flourish, according to a new study published in the journal Psychological Bulletin.
The researchers say the findings have significant implications for the way we educate children, whose inherited IQ can increase. This is especially true during early childhood if they are given the right kind of stimulation and attention.
“Genetic influences don’t run the show, nor do environmental effects. It’s the genetic-environmental interplay that is the ringmaster,” said Dr. Louis Matzel, a professor of psychology in the School of Arts and Sciences at Rutgers University, New Brunswick.
“We educate children the hard way in this country. We go to impoverished high schools and try to remediate kids, which is a perfectly good thing to do. But it’s often too late; the time to reach those kids is when they start school, while their intelligence is most malleable.”
The research is based on an integrative review of recent studies on the nature of human intelligence. Matzel conducted the study with Bruno Sauce, a graduate student in Rutgers’ School of Graduate Studies.
Scientists measure the heritability of traits on a scale of 0.0 to 1.0. For example, eye color has a heritability score of .99, meaning that it’s highly genetic. Intelligence typically rates at .8, say the researchers. But although one’s IQ is very heritable, Matzel and Sauce believe people tend to underestimate the role of environment.
“Through interactions and correlations with the environment, genetic influences can be expressed in wildly different ways, and environmental influences are much more powerful than many scientists believe,” said Sauce.
Importantly, the researchers say that the heritability of IQ can be as low as .3 in young children, which leaves plenty of room for changes in IQ. But school systems often ignore this opportunity, focusing on increasing rote knowledge at the expense of critical thinking. Intervention programs then often fail to deliver lasting changes to children’s environment.
One example is Head Start, the federal program that provides low-income children with comprehensive early childhood education, nutrition, and parent-involvement services.
Matzel says that the IQ scores of children in Head Start tend to increase significantly while they’re part of the intervention, but often regress after they leave — a common criticism of these programs. He believes this is because the stimulation and encouragement received in Head Start is missing when the child returns to their more restrictive environment.
Another example is that of identical twins separated at birth. If their IQs are nearly identical, and they have equal opportunities in life, they will be equally smart as adults. However, if one is deprived of opportunities, his or her cognitive abilities will diverge, Matzel said. This sheds light on the very important role that environment plays in the establishment of an individual’s intelligence.
So while these twins may have the same basic mental equipment with which to face the world, the twin raised in the better environment can thrive while his sibling is thwarted. “The environment is the critical tool that allows our genetic equipment to prosper,” says Matzel.
Source: Rutgers University