Certainly sleep is not the only factor in the ripening of the brain, but it appears to be a significant one that paves the way to mature thinking and reasoning ability. Feinberg’s study reminds me of a billboard advertisement I once saw from a large insurance firm, which read: “Why do most 16-year-olds drive like they’re missing part of their brain? Because they are.” It takes deep sleep, and developmental time, to accomplish the neural maturation that plugs this brain “gap” within the frontal lobe. When your children finally reach their mid-twenties and your car insurance premium drops, you can thank sleep for the savings.
— Why We Sleep: Unlocking the Power of Sleep and Dreams (Matthew Walker), Loc. 1463–7