On page 89, Jensen states “Melatonin, a hormone critical to inducing sleep, is released two hours later at night in a teenager’s brain than it is an adult’s.” Jensen’s point is that teenagers have melatonin released later and tend to get them tired. This finding challenges the belief that it is good that the teenager is getting tired. As a result, the melatonin can be in the teenager’s system longer and might make it hard for them to get out of bed in the morning. This matters because melatonin adjusts the sleep-wake cycle for