New research using structural brain scans calls into question a popular measure of intelligence that presupposes consistency

PROBLEM: We routinely use IQ tests to predict our children's prospects for education and employment. But what if this measure, which hinges on consistency, is not that stable during adolescence?

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METHODOLOGY: The researchers, led by University College London professor Cathy Price, administered IQ tests on 33 participants between the ages of 12 and 16 years in 2004. They repeated the tests four years later with the same subjects. On both occasions, the authors took structural brain scans of the subjects using magnetic resonance imaging.

RESULTS: The scientists found significant differences in IQ scores that correlated with changes in brain structures. An increase in verbal IQ score matched up with an increase in the density of grey matter in an area of the brain that's activated when articulating speech. Similarly, an increase in non-verbal IQ score was associated with an increase in the density of grey matter in the anterior cerebellum, which is associated with movements of the hand.

CONCLUSION: IQ rises or falls significantly during adolescence.

IMPLICATION: The practice of assessing children early in life and determining their course of education may need to be reevaluated. As Price puts it in a statement: "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."

SOURCE: The study, "Verbal and Nonverbal Intelligence Changes in the Teenage Brain," was funded by the Wellcome Trust Centre and is published in the journal Nature.

Image: l i g h t p o e t/Shutterstock.