October 20, 2011 12:37 PM

IQ scores fluctuate dramatically in kids, study says

By
Ryan Jaslow
Topics
News ,
Kids and family ,
Research

(Credit: istockphoto)

(CBS) If you think intelligence is set in stone, think again.

A new study shows that IQ can fluctuate dramatically during adolescence, with some teens raising or lowering their scores by about 20 points.

Psychologists have long believed that intelligence was fixed, and parents and educators often use IQ scores to determine whether children are "gifted" or need extra help at school. But the study suggests things are a bit more complicated.

For the study - published in the Oct. 18 issue of Nature - British researchers gave IQ tests to 33 children between the ages of 12 and 16. Four years later, researchers re-tested the same adolescents and found that about one-fifth of the kids fluctuated from one IQ category to another - such as from average to above-average intelligence, or vice versa. Some students' IQ rose as high as 21 points, while others fell by up to 18 points.

"A change in 20 points is a huge difference," study author Professor Cathy Price, a senior research fellow at Wellcome Trust Centre for Neuroimaging in the U.K, told WebMD. "If an individual moved from an IQ of 110 to an IQ of 130, they move from being 'average' to 'gifted.' And if they moved from 104 to 84, they move from being high average to below average."

Brain scans of the children confirmed that changes in IQ were mirrored by structural changes in the brain. That led the researchers to say that "these changes in IQ are real," study co-author Dr. Sue Ramsden, research assistant at Wellcome Trust, said in a written statement.

What's behind the rise or fall in brainpower? The authors said more research is needed to pinpoint the cause, but indicated that some children might simply be early or late bloomers. So parents shouldn't be so quick to give up on a seemingly dim-witted kid - or assume their smart child is set for life.

"We have to be careful not to write off poorer performers at an early stage when in fact their IQ may improve significantly given a few more years," Price said in the statement.

Price said in the statement that adults as well as youngsters could show changes in intelligence.

Will this study change the way you look at IQ tests?


Add a Comment
by jwpsych October 20, 2011 4:34 PM EDT
Statistically speaking, IQ scores do not represent a fixed point on the intellectual level continuum. They are an estimate of ability level. For instance, in consideration of the standard error of measurement, there is a 95 percent probability that a score of 110 represents an intellectual level that falls somewhere within the range of scores between 105 and 115. At 105, the IQ score is average; at 115, the IQ score is high average. Even this range of scores may be negatively affected by the testee's mood, physical feelings, shyness, level of attention, and many other factors. In considering scores with a 20 point difference (ex: 110/130), the possibility that the intellectual level represented by the 110 score actually fell higher in the range (115) and the 130 estimate actually fell lower in it's range (124) reveals the possibility that the 20 point difference between scores is actually only 9 points. Again, let me stress, IQ scores are estimates, providing a statistical range of scores that represent the level of intellect at which the testee performs on a given day. No, this study will not change the way I look at IQ tests. I feel it only confirms the interpretive process currently used by psychologists.
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