Why We Cry?

Our tears are far more important than scientists once believed.

- Mandy Oaklander

There's a lot scientists don’t know—or can’t agree on—about people who do cry. Charles Darwin once declared emotional tears “purposeless”, and nearly 150 years later, emotional crying remains one of the human body’s more confounding mysteries. Though some other species shed tears reflexively as a result of pain or irritation, humans are the only creatures whose tears can be triggered by their feelings. But why?

Researchers have generally focused their attention more on emotions than on physiological processes that appear to be their by-products. “scientists are not interested in the butterflies in our stomach, but in love,” writes ad Vingerhoets, a professor at Tilburg University in the Netherlands and the world’s foremost expert on crying, in his book, Why Only Humans Weep.

But crying is more than a symptom of sadness, as Professor Vingerhoets and others are showing. It’s triggered by a range of feelings—from empathy and surprise to anger and grief—and unlike those butterflies that flap around invisibly when we’re in love, tears are a signal that others can see. That insight is central to the newest thinking about the science of crying.

For centuries, people thought tears originated in the heart. A prevailing theory in the 1600s held that emotions—especially love—heated the heart, which generated water vapour in order to cool itself down. The heart vapour would then rise to the head, condense near the eyes and escape as tears. Finally, in 1662, a Danish scientist named Niels Stensen discovered that the lacrimal gland was the proper origin point of tears. That’s when scientists began to unpack what possible evolutionary benefit could be conferred by fluid that springs from the eye. Stensen’s theory: Tears were simply a way to keep the eye moist.