In this brain video Dr. Greg Berns talks about a new study using brain imaging to study teen brain development. It turns out that adolescents who engage in dangerous activities have frontal white matter tracts that are more adult in form than their more conservative peers.

Risky Behavior in Adolescents May Signal Mature Brain 

PLoS Journal Article: “Adolescent Engagement in Dangerous Behaviors Is Associated with Increased White Matter Maturing of Frontal Cortex”