Humans produce tears for a variety of reasons. Some of these have nothing to do with why people cry. If you’re cutting up an onion or suffering from seasonal allergies, your eyes may be brimming with tears. This is not emotional crying, but instead it is the act of the eyes producing tears to lubricate the eyes. In fact there are three types of tears: basal, reflex and emotional, which all occur for different reasons.
Basal tears are released regularly to keep your eyes lubricated. Reflex tears are those produced when irritants bother our eyes. Emotional tears are produced in the grip of extreme emotions: sadness, anger, and sometimes even laughter. Furthermore, we tend to produce emotional tears when we get injured, and some researchers suggest that the body doesn’t really differentiate between emotional and physical pain, even if the mind can.
There are many theories on why people cry emotional tears. One such is that there are proteins in tears, which are the same components in certain hormones. One of the biggest of these is prolactin, present in greater levels in women than in men. Women use prolactin in large supply when they are nursing infants, and in the first few days after having a baby, breastfeeding that baby may produce very strong emotional response as prolactin levels increase massively. Women also report feeling very calm, sleeping or spaced out during the first few weeks after a baby’s birth because of the high levels of this hormone.
Not only does prolactin stimulate lactation, but it also tends to have an overall calming effect. It may be the case that prolactin, and other hormones like it are part of a mood regulation system. When we perceive physical or emotional pain, these hormones may build, and produce greater amounts of tears. Thus people cry, and this release may be calming too, helping to restore mood.
It also should be kept in mind that crying is the natural province of the infant. Babies come into this world and most immediately begin crying (though they don't always produce tears immediately), and they will use this communication device pre-language development to communicate all their desires. But, studies also show that boy’s cries may be ignored for slightly longer, and especially in certain cultures, girl’s cries are attended to immediately. From birth we may be taught there are immediate rewards for crying, or that it is of little purpose, depending on our gender.
Whether or not people cry as adults may have much to do with the way their society treats tears. In many societies, tears in men are only acceptable at a few occasions, perhaps a funeral. This is unfortunate indeed; especially when boy children are told not to cry regularly, and many men have felt cut off from expressing emotions of grief that could help them heal from emotional wounds. Instead anger becomes the preferred emotion because it is more “male,” and men may need to work very long and hard to access the grief behind anger.
Women, conversely, may cry more easily not simply because they release more prolactin, but because conventionally, their society accepts their crying. When people cry, especially women, they may be viewed as “emotional” as though this is a negative characteristic. On the other hand, most therapists will point out that crying is likely to be a great way to release an emotional response and restore the mind to a quieter place. The man who bottles his emotions may ultimately be more negatively emotional than the woman who lets her emotions out in the release of crying.
Despite these theories, no single answer exists as to why people cry from emotional and physical pain. Having the tear ducts well up with unshed tears is much more easily explained when something is bothering your eyes. There is suggestion though that there are both nature/nurture reasons for why people cry. Women may have more prolactin, but in some cultures men can be found weeping and sobbing just as openly as women. There may be evolutionary, cultural and physiological components all combined to explain our tears. What is understood is that crying, especially in periods of grief or strong emotion, is often emotionally beneficial, as long as the person does not feel guilty for having displayed such emotion.