Intelligence changes in the teenage brain.

Researchers have found that IQ can rise or fall during the teen years and that the brain's structure reflects this uptick or decline. The result offers the first direct evidence that intelligence can change after early childhood and provides new hope for boosting the brain's abilities.

Although researchers debate what IQ tests actually measure, they agree that scores can predict our ability to learn and perform certain tasks, and to some degree forecast our later academic achievement and job performance. Scores have long been thought to stay relatively stable throughout our lives; the few studies that have shown some variation in IQ could not rule out measurement errors or differences in testing environment as the cause.

So neuroscientist Cathy Price of University College London and colleagues looked beyond the scores. They tested 33 teenagers—19 boys and 14 girls—in 2004, when they were 12 to 16 years old, and again in 2008, when they were 15 to 20 years old. Each time, the teens took IQ tests that measured their verbal and nonverbal abilities. Then, using magnetic resonance imaging, the researchers scanned the teenagers' brains while they performed verbal tasks, such as reading or naming objects, and nonverbal tasks, such as solving visual puzzles with their hands. The idea was to match their test scores with a picture of their brain's structure and activity at each time.

The test results revealed dramatic changes: between their first testing and their second, the teens' verbal and nonverbal IQ scores rose or fell by as many as 20 points (on a scale for which the average is 100). Some teens improved or declined in just their verbal or nonverbal skills or improved in one area and declined in the other.

The brain scans mirrored the score differences. In teens whose verbal IQ scores had increased, for example, the scans showed increased gray matter density in a region of the brain activated by speech. Teens whose nonverbal skills had improved showed changes in a brain region associated with motor movements of the hand


[Source]

A link to the article in Nature can also be found here: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10514.html
​

The changes are said to be linked to structural changes in the brain, not in hormonal changes.

Which raises difficult questions in how children are assessed and whether it is correct to assess and test children, knowing that their intelligence could very well fluctuate as they grow and develop? In other words, a gifted child at 13 may not be deemed gifted by the time that child is 15 and vice versa. Even more intriguing:

Other studies from the Wellcome Trust Centre for Neuroimaging and other research groups have provided strong evidence that the structure of the brain remains 'plastic' even throughout adult life. For example, Professor Price showed recently that guerrillas in Columbia who had learned to read as adults had a higher density of grey matter in several areas of the left hemisphere of the brain than those who had not learned to read. Professor Eleanor Maguire, also from the Wellcome Trust Centre, showed that part of a brain structure called the hippocampus, which plays an important part in memory and navigation, has greater volume in licensed London taxi drivers.

"The question is, if our brain structure can change throughout our adult lives, can our IQ also change?" adds Professor Price. "My guess is yes. There is plenty of evidence to suggest that our brains can adapt and their structure changes, even in adulthood."

[Source]
​