Probably the most interesting fact about human development is the frontal cortex is the last part of the brain to fully maturity, it's not completely online until you're about 25 years old, which is mind-boggling to think about, what does that explain? That explains why adolescents are adolescent in their behavior. The sensation-seeking and the risk-taking, and the highs are higher and the lows are lower, because the steadying frontal cortical hang there isn't fully up to speed yet and everything else is a gyroscope, out of control. And that's where the impulsivity is from, and that's where the extremes of behavior, and that's why most crime is committed by people at a stage whose frontal cortex is not fully developed yet. That is why most people who do astonishing wondrously self-sacrificial things; don't have a frontal cortex. That's fully in gear yet either, and is not in a position to convince them yet at somebody else's problem, look the other way. That's why young adults are, exactly how they are, because the frontal cortex isn't quite there yet, and what you have, as a result, is more adventurousness and more open to novelty and more likelihood of seeing somebody who is very different as in fact not to being that different after all, and more likely to grab a cudgel and smash in somebody’s skull who happens to seem like of them, and everything just the tone of everything is pushed up. One incredibly, important implication of that is, if the frontal cortex is the lost last part of the brain to fully mature, that means it’s the part of the brain that is most sculpt.