Explanation: Melatonin is a substance that is excreted at night and by which the brain sends signals that one should sleep, that is, a man / woman is feeling sleepy. When melatonin secretion decreases, the alertness increases, as is the case with Colby. Melatonin levels decrease at the base of the brain signal regardless of whether or not Colby slept enough the previous night. Feeling tired will induce some other receptors and consequent signals from the brain, but a natural decrease in melatonin throughout the day occurs normally.
Independent group contingency are reward systems in which members of a group (children) individually earn token reinforcers demonstrating ideal behavior.
