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The Science Behind Why People Cry

When was the last time you cried? Whether it was when you first held your child or last Thursday when you had an emotional release while you’re in one of your yoga classes, crying is part of being human.

Women are better at it than men, crying over 4,000 times throughout their adult lifetime, which is more than twice as much among men. But no matter the sex, why do people cry? What exactly happens when we cry?

Tears begin in the lacrimal glands.

The lacrimal glands are paired almond-shaped glands that secrete tears; we have one for each eye. The lacrimal gland sits between the eyelid and eyeball and produces three types of tears: basal, reflex, and psychic tears.

The basal tears are the “worker tears.” They keep your cornea lubricated so that your eyes don’t dry out. The reflex tears wash out any irritations from foreign particles like dust or vapors such as the chemical irritant produced from cutting onions. The third type, the psychic tears, is a natural response to a strong emotion you’re feeling, such as sadness, stress, anger, or even pleasure.

For the first two types, the tears go to the corner of the eye when we blink. But when the lacrimal gland overproduces, the tears drain into our nose. That’s why our nose starts running when we cry. And if the nose can’t drain the tears fast enough, these tears spill over onto our cheeks—and crying happens.

man crying

When did we start to cry?

We share the ability to produce tears with other species like cats and elephants. But humans are the only species that cry tears of emotion. In some way, our lacrimahl glands have evolved to become connected to our feelings. One theory is associated with how infants cry to get the attention of their mothers.

Infants scream to send a vocal signal because they can’t still communicate. Through excessive screaming, infants squeeze the muscles around their eyes. That mechanical pressure is detected by the sensory nerve endings that stimulate the lacrimal gland (just like what happens when we yawn). So when babies scream, they cry, too.

Ad Vingerhoets, professor and author of the book Why Only Humans Weep, explained that, in ancient times, the sound of a baby screaming didn’t only attract the mother but also the predators. Infants were somewhat trained to cry more than scream to lower that risk. Over the years, crying has become our subdued way to ask for help. It persists when we become adults, and our emotions get more complicated.

Why do we cry as adults?

As adults, we don’t only cry for help. We cry for all kinds of emotions, but often, we cry because of loss and affection. These are intense emotions that, physiologically, stimulate our lacrimal glands. We also tear up because of empathy. When we see others in pain and cry, we read their cues and subconsciously mimic their behavior. This explains the concept of contagious crying in infants. Recent studies also found that mimicry can extend to heart rate and pupil diameter, which, again, can stimulate the lacrimal gland.

Physiologically, crying is excess tears that your nose can’t drain fast enough. But over time, we have evolved to use our lacrimal glands to make sense of intense emotions within us and others.

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