Recent research indicates the human brain keeps maturing in the teen years. Reasoning and judgement processes develop well into early or even 20s.
Prof.Laurence Steinberg of the US notes brain scans have given biological backing to commonsense notions about teen behavior, like their impulsiveness and vulnerability to peer pressure.
It's one thing to say teens don't control their impulses as well as adults, but another to show that they can't, he said. As for peer pressure, the new brain research "gives credence to the idea that this isn't a choice that kids are making to give in to their friends, that biologically, they're more vulnerable to that," he said.
Consider the lobes at the front of the brain. The nerve circuitry here ties together inputs from other parts of the brain, said Dr. Jay Giedd of the National Institute of Mental Health.
This circuitry weighs how much priority to give incoming messages like "Do this now" versus "Wait! What about the consequences?" In short, the frontal lobes are key for making good decisions and controlling impulses.
Brain scans show that the frontal lobes don't mature until age 25, and their connections to other parts of the brain continue to improve to at least that age, Giedd said.
The inexplicable behavior and poor judgments teens are known for almost always happen when teens are feeling high emotion or intense peer pressure, conditions that overwhelm the still-maturing circuitry in the front part of brain, Giedd said.
As Steinberg sees it, a teenager's brain has a well-developed accelerator but only a partly developed