"- like, a little baby," Chioss makes a cradling gesture, "might not want to stop playing and take a nap, but if their parents keep playing with them when they're actually tired, they'll get more and more upset about everything from being sleepy, and still not want to sleep, because they don't have practice with knowing what to do with sleepiness. But if a three year old," she holds her hand at about her shoulder height, "wants to stay up late playing, most parents will let them try it at least a couple of times, and they can all see what happens, and if what happens is that the kid is fine the next day, they can keep doing that, and if what happens is that the kid isn't fine the next day, but notices it and deals with it by themselves, they can use their own judgment about whether to keep doing it. But if what happens is that the next day they're miserable and mean to everyone and can't pay attention to anything they're doing because they're too tired, and that night they try to stay up playing again, they are acting like a baby, and their parents will probably stop them."