Is there a period in human development when we have a “teenage brain?”
That’s a great question because there is even the issue that has been raised as to whether adolescence is “for real” in a biological sense. I mean, there’s plenty of cultures where essentially, you know, you’re married off to somebody when you’re 13 or some such thing, and all you are is like an adult with acne, that it’s not a special stage. And the suggestion that this is something that the West kind of invented, dealing with the fact that there’s now viewed as a delay between when one starts one’s main occupation, when one finishes education, and at the earlier end when the hormones start. Ah, we’ll call this magical period in between adolescence. So if it’s just an artificial construct, everything the brain is doing during development should just be in a smooth curve like this, where somewhere arbitrarily oops, that’s what we call adolescence is starting. Made-up concept. But that’s not what you see, because it is distinctive.
Parts of the brain are pretty much going full bore by the time you’re a year old, 5 years old. There’s parts of the brain, the limbic system which is involved centrally in emotion, which are pretty much all there by the time adolescence is starting. Then another distinctive feature of adolescence, which tells you it’s not just this: The hormones start. So what’s the frontal cortex doing there? The easiest picture would be if it’s the one that’s just sluggishly going on. That’s not what you see though. Interestingly, by the beginning of adolescence your frontal cortex is bigger than it’ll be as an adult.