Teens get smarter as their minds get quicker

A group of psychologists at University of Texas at San Antonio has found that adolescents become smarter because they become mentally quicker.

This is the first time psychologists have been able to confirm this important connection.

To find the relationship between these two phenomena, the UTSA psychologists analysed the results of 12 diverse intelligence and mental speed tests administered to 6,969 adolescents (ages 13 to 17) in the 1997 National Longitudinal Survey of Youth.

Intelligence was measured by performance on cognitive tests of diverse abilities, such as vocabulary knowledge, math facts, and mechanical comprehension.

Mental speed showed up in timed tests of computing and coding—matching digits and words and other arithmetic tasks.

In both of these categories, the researchers could see that the older teenagers did better and worked faster than the younger ones.

Then, running the data in numerous ways, they discovered that the measured increase of intelligence could be accounted for almost entirely by the increase in mental speed.

This is what we expected to find. After all, “performance on intelligence tests reflects, in part, the speed of acquiring knowledge, learning things, and solving problems,” said lead author Thomas Coyle.

Those cognitive processes are related to how fast the brain is working—and all that improves during the teenage years, he added.

The study will appear in the forthcoming issue of Psychological Science.