[ 2011-10-20 ]

Intellectual performance can both improve and deteriorate in adolescence

IQ 'can change in teenage years'
The mental ability of teenagers can improve or
decline on a far greater scale than previously
thought, according to new research.

Until now the assumption has been that
intellectual capacity, as measured by IQ, stays
quite static during life.

But tests conducted on teenagers at an average age
of 14 and then repeated when their average age was
nearly 18 found improvements - and deterioration.

The findings are published in the journal Nature.

They have implications for how pupils are
assessed, and the age at which decisions about
their futures are made.

This study 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 show that a change in verbal IQ was
found in 39% of the teenagers, with 21% 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 associated with movements of the hand.

The work was led by Professor Cathy Price of the
Wellcome Trust Centre for Neuroimaging at
University College London and is published in the
journal Nature.

The paper suggests that the results could be
"encouraging to those whose intellectual potential
may improve and… a warning that early achievers
may not maintain their potential".

Professor Price said: "We have a tendency to
assess children and determine the course of their
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 age when in fact their IQ
may improve significantly given a few more
years."

The research did not seek to understand the causes
of the changes.

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.

"I think the change came in school I started doing
subjects that really interested me, that I was
engaged in, then I found it easier and far more
interesting."

The research was funded by the Wellcome Trust, one
of many projects supported under its programme of
Understanding the Brain.

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.

Source - BBC

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