Whether you cry at the death of a pet, or simply because you've just received your first big winter heating bill, the precise physiological reasons why we weep remain a mystery.
"There is very limited research indicating why someone cries," says Dr, Bruce Rabin, medical director of the UPMC Healthy Lifestyle Program. However, in general, it is clear that there are nerves that go from the brain to the glands that produce tears."
Rabin says it's unlikely that a single part of the brain initiates crying.
"There are parts of the brain involved with different emotions. They all impinge up on the area that induces crying," he says. "We know, for example, that in some people, but not all people, fear, anger, disappointment, being criticized, will induce tears. Why does this occur in some people and not in others?"
These different emotions, Rabin says, may all be directed to a single part of the brain that decides whether or not to turn on the waterworks.
"Crying often makes people feel better; this whole thing of 'let it out.' We also known that taking some deep breathes makes you feel better. Often, when people are taking deep breaths to calm themselves, they imagine the things that are bothering them leaving with the breaths. You feel better because the worries are coming out of your body. We don't know why it produces calmness."
The difference between laughing and crying relate to the way each of us processes intense emotional stimulation, says Dr. David Falcone, a professor of psychology at La Salle University in Philadelphia.
"It at least involves a certain kind of change in general arousal and then our own interpretation of the experience," he says.
"Think of a young child on a swing at the park. As a parent pushes the swing, as it reaches a low to moderate height, the motion changes create similar changes in arousal that have the child catching her breath in delight. But if the swing goes just beyond this point to a higher peak, the descent is too fast, the arousal level rises too fast, and the child's giggles and chirps turn to screeches of terror. The child cries.
"An increase in arousal can occur for many reasons. It is the way we make sense of these reasons that might be the difference between laughing or crying. Leaving a party, if we turn in surprise at a man falling down a flight of stairs, we might smile if it is because he is inebriated ... but we would most likely be saddened if it was because he was crippled."
If it feels so good to hurt so bad, as Elton John sings in "Sad Songs (Say So Much)," there's likely a good reason.
"Over time, if you don't express your feelings they start to wear on you," says Robert Faux, part-time professor in the Psychology and Education Department at the University of Pittsburgh. "You need to be able to express your feelings, what you're thinking in some way. Just in terms of mental health, it's really critical to express what you have going on inside."
