Such is the chemistry of the brain that the longer that good-night hug lasts, the more it produces the feeling of a bond, even if one is thinking "this doesn't mean a thing." The lesson would seem to be that unless you are already attached, it would be a good idea to keep those hugs short. Don't blame me. Blame oxytocin.
I can imagine protests. "Why didn't anyone tell me that it only takes ten seconds or so for my brain to release oxytocin? Why didn't anyone tell me that my vulnerability might be even greater in the dark?"
These are the wrong questions, for such little findings of brain science merely ratify common sense. Long before people knew about neurotransmitters, they understood that it was wise not to stay out too late, smart not to turn out the lights, and good to put limits on the touching of bodies. Long before they knew that the frontal lobes aren't fully developed until about age twenty-five, they knew that young people need supervision and shouldn't be left alone. Long before they knew how the endocrine system works, they knew that exhaustion and inactivity make not only the muscles but the virtues lose their tone, so that if one doesn't want the mice of temptation to turn into ravening beasts, one must get proper sleep and exercise. Long before they had statistical confirmation from sociologists, they knew that a child needs a mom and a dad.
Once upon a time, such bits of mother wit, gleaned from centuries of experience, were passed on from generation to generation. To us they seem new because we have broken the generational transmission belt and forgotten what everyone used to know. Instead of turning to our grandmothers, we turn to biochemists and statisticians. We believe the obvious only when we count it on a calculator or isolate it in a test tube.