New research shows that teenagers' brains aren't fully insulated, so the signals travel slowly when they need to make decisions. Neuroscientist Frances Jensen, who wrote The Teenage Brain, explains.
This insulation process starts in the back of the brain and heads toward the front. Brains aren't fully mature until people are in their early 20s, possibly late 20s and maybe even beyond, Jensen says.
"The last place to be connected — to be fully myelinated — is the front of your brain," Jensen says. "And what's in the front? Your prefrontal cortex and your frontal cortex. These are areas where we have insight, empathy, these executive functions such as impulse control, risk-taking behavior."
This research also explains why teenagers can be especially susceptible to addictions — including drugs, alcohol, smoking and digital devices.