A new brain imaging study has found that teenagers who indulge in dangerous activities have a more mature brain as compared to their less adventurous peers.
The study, which focused on teen behaviour, found that adolescents with risky behaviour have frontal white matter tracts that are more adult in form than their more conservative peers.
The brain goes through a course of maturation during adolescence, and does not reach its adult form until the mid-twenties.
According to a long-standing theory of adolescent behaviour, this delayed brain maturation is the cause of impulsive and dangerous decisions in adolescence.
But, the new study, which used a form of magnetic resonance imaging (MRI) called diffusion tensor imaging (DTI) to measure structural changes in white matter in the brain, has questioned the above theory.
Emory University and Emory School of Medicine neuroscientists wanted to better understand the relationship between high risk-taking and the brain's development.
"In the past, studies have focused on the pattern of gray matter density from childhood to early adulthood. With new technology, we were able to develop the first study looking at how development of white matter relates to activities in the real world," said Dr. Gregory Berns.
Gray matter is the part of the brain made up of neurons, while white matter connects neurons to each other. As the brain matures, white matter becomes denser and more organized. Gray matter and white matter follow different trajectories. Both are important for understanding brain function.
The study enrolled 91adolescents ages 12 through 18 over a three-year period.
The researchers measured the levels of engagement in dangerous behaviours via a survey that included questions about the teens' thrill seeking behaviours, reckless behaviours, rebellious behaviours and antisocial behaviours.
DTI was used to measure corresponding structural changes in white matter.
"We were surprised to discover that risk-taking was associated with more highly-developed white matter - a more mature brain. We were also surprised to learn that except for slightly higher scores in risk-taking, there was no significant difference in the maturity of the white matter between males and females," said Berns.
Berns has suggested that doing adult-like activities requires sophisticated skills.
The study's findings have been published in the journal PLoS ONE.