A teenager’s IQ can rise or fall as many as 20 points in just a few years, a brain-scanning team found in a study published Wednesday that suggests a young person’s intelligence measure isn’t as fixed as once thought.
The researchers also found that shifts in IQ scores corresponded to small physical changes in brain areas related to intellectual skills, though they weren’t able to show a clear cause and effect.
“If the finding is true, it could signal environmental factors that are changing the brain and intelligence over a relatively short period,” said psychologist Robert Plomin at Kings College in London, who studies the genetics of intelligence and wasn’t involved in the research. “That is quite astounding.”
Long at the center of debates over how intelligence can be measured, an IQ score—the initials stand for “intelligence quotient”—typically gauges mental capacity through a battery of standardized tests of language skill, spatial ability, arithmetic, memory and reasoning. A score of 100 is considered average. Barring injury, that intellectual capacity remains constant throughout life, most experts believe.
But the new findings by researchers at University College London, reported online in Nature, suggest that IQ, often used to predict school performance and job prospects, may be more malleable than previously believed—and more susceptible to outside influences, such as tutoring or neglect.