Genes and environment affect intelligence

January 18, 2012 — Our genes may play a role in shaping how sharp we remain as we grow older.

Researchers analyzed genetic material from about 2,000 people to determine how intelligence changes from childhood to adulthood. All of the study participants took tests that measured their general intelligence at age 11 and then again when they were 65, 70, or 79.

Genes accounted for about 24% of the mental changes that occur across the life cycle.

This means that environment also plays a big role in shaping and maintaining our intelligence and mental ability as we grow older.

Now it is up to gene hunters to identify the specific genes responsible for these changes. “The study will encourage those researchers looking for the genetic and environmental contributions to why some people's cognitive functions age better than others,” says researcher Ian J. Deary, PhD, in an email. He is a professor of psychology at the University of Edinburgh in the U.K.

The new findings appear in Nature.

It’s Not All in Your Genes

Yes, there is a significant genetic component to the change in our intelligence from childhood to late adulthood, says Clark McKown, PhD. He is the director of the Rush NeuroBehavioral Center in Skokie, Ill.

The new study is “scientifically exciting and important,” but there are a lot of "ifs" here, he says. “If we can figure out what the genetic [indicators] are of [mental] decline, and if we can develop a screening test, and if we can develop therapies, we may be able to screen people early in life and intervene to lower their risk,” McKown says.

None of this is possible today. Stay tuned, he says. “In the meantime, there is a huge environmental contribution to maintaining our [mental] abilities as we age,” he says.

Eating a healthy diet, exercising regularly, and maintaining an active social life can help you stay mentally sharp, McKown tells WebMD. “Genes are not destiny by any stretch,” he says.

Another Rush University neuropsychologist agrees. S. Duke Han, PhD, says that there are things we can all do today that will affect our risk for developing mental problems as we age.

“It is not all in the genes,” he says. “There is room for manipulation.”

SOURCES:

Deary, I. Nature, Jan. 2012. In press.

Ian J. Deary, PhD, professor of psychology, University of Edinburgh, U.K.

S. Duke Han, PhD, neuropsychologist, Rush University Medical Center, Chicago.

Clark McKown, PhD, director, Rush NeuroBehavioral Center, Skokie, Ill.