Skip to content

    Health & Parenting

    Font Size

    IQ Scores of Teens May Change Over Time

    Study Shows IQ Scores Can Fluctuate Over the Course of Several Years
    WebMD Health News
    Reviewed by Laura J. Martin, MD

    Oct. 19, 2011 -- A teen's IQ is not set in stone, according to a study published today in Nature. Instead, the standard measure of intelligence -- often used to predict future success -- can fluctuate dramatically.

    "The results indicate that an early developer doesn't necessarily continue to excel; and a late developer can catch up. Educators already know this," study researcher Cathy Price, PhD, tells WebMD in an email. "The more relevant point is that, if IQ changes are real (as we claim), they are not measuring a capacity to do well. They are measuring how well the individual is doing at a fixed time."

    Price, a professor at the Wellcome Trust Centre for Neuroimaging at University College London, and colleagues, tested 33 "healthy and neurologically normal" adolescents aged 12 to 16. Their IQ scores ranged from 77 to 135, with an average score of 112.

    Four years later, the same group took another IQ test. While the average score of 113 was only one point greater than the previous test, the range of scores was quite different: 87 to 143. Individually, the results were quite striking, as participants showed as much as an 18-point drop in IQ, while others shot up as high as 21 points.

    The researchers also broke down the scores by verbal IQ, a measure of language, arithmetic, general knowledge and memory, and performance IQ, which focuses on visual problem solving. Scores fluctuated by as much as 23 points in verbal IQ and 18 in performance IQ.

    "A change in 20 points is a huge difference," Price says. "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."

    Overall, the researchers report, one-fifth of the kids tested moved from one IQ category to another, from average to below average, for example.

    Brain Changes

    Each of the participants also underwent brain scans -- a combination of functional and structural imaging -- at the time that they were given the IQ tests.

    Today on WebMD

    Girl holding up card with BMI written
    Is your child at a healthy weight?
    toddler climbing
    What happens in your child’s second year.
    father and son with laundry basket
    Get your kids to help around the house.
    boy frowning at brocolli
    Tips for dealing with mealtime mayhem
    mother and daughter talking
    child brushing his teeth
    Sipping hot tea
    boy drinking from cereal bowl
    hand holding a cell phone
    rl with friends
    girl being bullied
    Child with adhd