Why Do Humans Cry? Exploring the Science behind Tears

Why Do Humans Cry? Exploring the Science behind Tears

Humans cry for many reasons — when we chop onions, get a piece of dust in our eyes, watch a sad movie, etc. We also constantly produce what are known as “basal” tears, which keep the surface of our eyes lubricated. But in this post, the Eyesthetica team of oculofacial surgeons in Los Angeles wants to explore the science behind emotional tears, or the waterworks that occur when we feel sad, angry, fearful or joyful. 

Are We Wired to Cry to Get Attention?

Although scientists can’t agree on the reason(s) why we cry emotional tears, they have many plausible theories.

One of the most widely accepted theories is that we are biologically wired to cry to signal to other people that we are in distress and vulnerable. Our tears signal to others that we have a problem that is beyond our abilities. Imagine an infant that cries out to his mother because he’s hungry or tired; when the mother hears the crying, she comes to his rescue. From an evolutionary context, tears and vulnerability trigger social bonding and human connection. Taking care of each other in times of need improves communication and teamwork and increases the likelihood of survival.

Scientific evidence shows that emotional tears have a different chemical makeup than basal tears and reflex/irritant tears (that occur when chopping onions). Emotional tears have more protein and a higher viscosity than other tears, so they stick to the skin longer. They run down the face more slowly, causing noticeable streaks likely to attract the attention of other people.

Our Hormonal Makeup Can Influence Crying

According to a 2011 study published in the Journal of Research in Personality, women cry an average of 5.3 times a month, while men cry an average of 1.3 times per month. Science points to our hormonal makeup as the culprit.

A hormone called prolactin is thought to promote crying, just as testosterone is thought to stifle the act. Women have higher levels of prolactin and men have higher levels of testosterone.

If you find that you are tearing up too much, or that your eyes constantly feel dry, you should have them checked out by our team. Please call (213) 234-1000 or email the Eyesthetica team and schedule an appointment today.