Our competitive edge is our ingenuity

From the excellent book The Teenage Brain by Frances E. Jensen MD:

The frontal lobes make up more than 40% of the human brain's total volume...The frontal lobes are the seat of our ability to generate insight, judgment, abstraction, and planning. They are the source of self-awareness and our abilities to assess dangers and risk; so we use this area of the brain to choose a course of action wisely.

...Our competitive edge is our ingenuity, brains over brawn. This edge happens to take the longest time to develop, as the connectivity to and from the frontal lobes is the most complex and is the last to fully mature.

The connectivity of the brain slowly moves from the back of the brain to the front. The very last places to "connect" are the frontal lobes. In fact, the teen brain is only about 80% of the way to maturity. That 20%
gap, where the wiring is thinnest, is crucial, and goes a long way toward explaining why teenagers behave in such puzzling ways - their mood swings, irritability, impulsiveness, and explosiveness; their inability to focus, to follow through, and to connect with adults; and their temptations to use drugs and alcohol and to engage in other risky behavior. When we think of ourselves as civilized, intelligent adults, we really have the frontal and prefrontal parts of the cortex to thank.