What is the scientific explanation for why people cry?

Question

I do not mean what events cause people to cry, I mean why is it that we react to these events in such a way? In other words, why does some salty liquid come out of our eyes and snot out of our nose? Are there other animals that cry or something of the like?

Which other animals cry and in what circumstances?

How is it that we are discharging these chemicals or hormones or whatever through tears and snot? Is the composition of snot when crying any different than when you have a runny nose from a cold, for example? This is not all adding up for me yet.

Answer 1

Grief - specifically crying - is a special emotional ability of more advanced mammals. As recently reported by a researcher named Hall from New Zealand, it appears to be a part of our fight-or-flight system which is evolved specifically for animals with highly-developed brains. (Yes other animals cry; not all "lacrimate" or produce tears.) It works something like this: a specific stimulus - real, or in our imagination or memory - would normally make us angry. But more advanced mammals can't afford to just have an anger reaction any old time, so the anger response is "primed" and ready to be released, but is "caught" by higher brain functions which recognize that there is no PHYSICAL reason to be angry. Crying - the grief response - allows us to discharge the electrochemical energy of the "primed" anger response in a safe way which does not stress the system without actually going into a fight reaction. The "snot and tears" are, at least in part, a flushing mechanism which breaks down and washes out the stress-response chemistry so that it doesn't build up and force us into an actual stress response. A lot of grief responses are hard to attach to things that relate to anger, but the more you understand human emotional responses, the more you begin to see how tears always relate to situations that would cause a "fight" response if we didn't have this way of avoiding unnecessary fight responses. This is very new theory by the way and isn't widely accepted yet by neurobiologists, but it's by far the best explanation of crying and grief that I've ever come across.

Answer 2

"As humans we laugh and cry, but seldom do we question how, or why. There are many processes involved in both responses. Cultures around the world allow both crying and laughing as acceptable behaviors. With crying, as well as laughter, the body goes through physical or chemical changes. Crying and laughter are beneficial to us both emotionally and physically. We must have them to function in the world.

Crying is a more complicated process than one would at first imagine. First of all, there are really three different types of tears. Basal tears keep our eyes lubricated constantly. Reflex tears are produced when our eyes get irritated, like with onions or when something gets into our eyes. The third kind of tear is produced when the body reacts emotionally to something. Each type of tear contains different amounts of chemical proteins and hormones. Scientists have discovered that the emotional tears contain higher levels of manganese and the hormone prolactin, and this contributes in a reduction of both of these in the body; thus helping to keep depression away. Many people have found that crying actually calms them after being upset, and this is in part due to the chemicals and hormones that are released in the tears."

Answer 3

some animals cry

and to answer your question, is a biological reaction to pain, high emotion, hush weather conditions and so on.

there are some people who are unable to cry, due to the fact that their "crying glande" doesn't work.

Answer 4

brain and emotions plus hormones = crying.

animals im not to sure about im sure they feel something

Answer 5

Why not take your question to the Education section? Or the Science section (not being funny seriously). See if you will get better answers.

Peace Out.