It's common sense to think that teenage recklessness come from their immaturity - but could the opposite actually be true?

A team led by psychiatrist Gregory Berns of Emory University conducted a study with the paradoxical result - the more mature the teenager's brain, the more reckless they become:

In a paper just published in PLoS ONE — a journal of the Public Library of Science — a team led by psychiatrist Gregory Berns of Emory University in Atlanta shows that adolescents who engage in more dangerous activities have white-matter pathways that appear more mature than those of risk-averse youths. White matter is essentially the brain's wiring — the neural strands that connect the various gray-matter regions, where the actual nerve cells reside, that are otherwise independent of one another. Maturation of white matter is important because it increases the brain's processing speed; nerve impulses travel faster in mature white matter.

Berns and his colleagues recruited 91 kids ages 12 to 18 and asked them to fill out a questionnaire about their tendency to engage in behaviors such as driving without a license, having unprotected sex and using drugs. Then they had the kids undergo a relatively new kind of brain scan called diffusion tensor imaging, a type of magnetic resonance imaging that is used to look at dense tissues like white matter. After analyzing the scans, the authors found a strong correlation between how risky the students described their behavior to be and how sophisticated their white matter was. The more mature the look of the brain, the more risk-taking the teenager tended to report.

John Cloud of Time Magazine has the story: Link