Teens' IQs can go up and down, says study

Updated on: Friday, October 21, 2011

Scientists have discovered that the mental ability of teenagers can improve or decline on a much greater scale than previously thought, a finding they say can have widespread implications for education.

Until now, it has been assumed that the intellectual capacity, as measured by IQ, remains quite static over the course of a lifetime.

But researchers at University College London, who carried out tests on teenagers at an age of 14 and then at 18, found improvements and even deterioration in their IQ levels, the BBC reported.

The findings, the researchers said, have implications for how pupils are assessed, and the age at which decisions about their futures are made.

Professor Cathy Price, who led the study the Wellcome Trust, said: "We have a tendency to assess children and determine their course of education relatively early in life, but here we have shown that their intelligence is likely to be still developing."

"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."

The study, which was published in the journal Nature, involved 19 boys and 14 girls, all undergoing a combination of brain scans and verbal and non-verbal IQ tests in 2004 and then in 2008.

The results showed that a change in verbal IQ was found in 39 per cent of the teenagers, with 21 per cent showing a change in "performance IQ" a test of spatial reasoning.

The findings are seen to have greater validity because for the first time the variations in IQ correlated with changes in two particular areas of the teenagers' brains.

An increase in verbal IQ corresponded with a growth in the density of part of the left motor cortex - a region activated during speech.

And an increase in non-verbal IQ correlated with a rise in the density of the anterior cerebellum an area linked to the movements of the hand.

The research did not seek to understand the causes of the changes, but the researchers said it could be "encouraging to those whose intellectual potential may improve and a warning that early achievers may not maintain their potential".

One explanation is that teenagers mature at relatively different ages with "early" and "late" developers while relative standards in education may play a part too.

One of the participants, Sebastian Friston, now aged 23, recorded a marked increase in IQ between the two tests from average to one of the highest categories.

Educated in the state sector, he told me he had struggled in his early years, needing remedial maths tuition, but is now planning a doctorate in computer engineering.

Future work may focus on how adaptable the brain may be beyond teenage years, and the implications for tackling mental diseases and other neurological conditions.

Teens' IQs can go up and down, says study

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