For teens, a tendency toward dangerous behavior is hard-wired into the brain. A developmental psychologist explains.

Question: Why are teenagers the most prone to recklessness?

Laurence Steinberg: Well, I think you can answer that question on different levels, so let's give it a shot. Think about adolescence from an evolutionary point of view, all right? I mean, adolescence is really the beginning of when we're supposed to be reproducing. And if you look at other species, at puberty the juveniles -- and because some viewers might not realize this, all mammals go through adolescence, and we can measure when they are in the adolescent period in terms of the puberty hormones -- so if you look at what happens at puberty in other species, the juveniles leave the home. And that is, you know, designed so that they don't mate within their family. But now, leaving the home is a very risk proposition. It's dangerous to leave the protection of the older animals that have raised you and protected you. I think that that's why risk-taking is built into adolescence as a part of the repertoire of behavior that's good, that's important and that's necessary for evolution.

Now, the conditions under which we evolved are not the same as the conditions that exist today. And so this general inclination for risk-taking, which may be an inherent feature of adolescence, may lead kids into difficult and dangerous situations now that didn't exist when we were evolving, although it was a pretty dangerous time to be a human being when we were evolving as well. And I think that this then helps to explain why the brain changes the way it does during adolescence, why you have this increase in novelty-seeking that is linked to the sexual changes of puberty. And this then encourages kids to pursue rewards and to engage in pleasurable and exciting behaviors like having sex. And I think that if -- that by the same token, you know, the brain's self-regulatory systems are still developing then, and they come online in adulthood, which is when, evolutionarily speaking, we need that because that's when we're raising the children that we have produced during the adolescent years, after we become fertile. So I think it makes a lot of sense, and that's why I think that it's probably futile to try to stop kids from being the way they are. I think it's good to educate them; they need to understand the potential harms and dangers that are out there. But I think we need to recognize that education alone is not going to prevent adolescent risky behavior.