Moved to Tears

The science of tears

Moved to Tears

The first time I saw my father cry, I was torn between great sadness and intrigue. It was like he was so sad, and that first tear was being dragged down his cheek by the weight of his woes. You can’t help but react yourself because whether it’s deep sadness or unadulterated joy, tears are the universal sign of emotion.

But why?

The reasons we cry are complex. They even stumped Darwin who couldn’t find an obvious evolutionary reason to justify the seemingly wasteful seepage of fluid through the eyes. Yet it’s clear that wherever you go on this planet, tears mean a lot to us, whether we’re the ones doing the weeping or we’re bearing witness to a literal outpouring of feeling.

Believe it or not, we humans are constantly ‘lacrimating’ (from the Latin for tear “Lacrima”) – producing fluid from our eyes. But not all forms of lacrimation are the same. Humans are thought to be the only species to shed three types of tears – basal, reflex and emotional tears.

The first two are quite easy to explain.

Basal tears are the maintenance beads of moisture that coat our eyes, keeping them free from bacteria and lubricating the surface of the eye. If you weren’t able to shed basal tears, you’d soon know about it. Your eyes would feel incredibly itchy, sore and unsurprisingly, dry!

Reflex tears kick in to protect our peepers from harm. Onions, gases or a sudden cloud of dust can cause you to tear up in an instant, flushing the eyes and washing away any those pesky and irritating particles.

And the third?

Emotional tears work in completely the opposite way. That’s to say that the trigger comes from within, rather than without!

Some scientists suggest that one of the reasons we have developed the ability to cry is as a literal release. We often talk about “feeling better after a good cry” and the science backs this up. The tears we shed as a result of intense emotion are packed with high levels of hormones like cortisol, which builds up when we’re stressed. Our tear ducts are like a little hole in a basin that lets water trickle out to avoid an inevitable deluge, and our tears act as a hormone disposal system. Which means the act of crying could be a physical process as well as psychological.

We share the ability to shed basal and reflex tears with apes, elephants and camels. But scientists have long believed that this is where the similarities end when it comes to crying, or so we thought. Scientists at the American College of Veterinary Ophthalmologists (animal opticians!) are setting out to prove that horses shed emotional tears too. They’ve found that horses produce more tears when they’re under stress and that the tears they produce show increased levels of the hormone cortisol in just the same way as humans.

So what are our tears made of other than water and hormones?

All tears are composed of similar ingredients – water, salts, enzymes and hormones. However, the ratio of ingredients varies between the three tear types and with each kind, tears change depending on their cause. The type and quantity of hormone can change dramatically, depending on the trigger. For example, joy or despair. So each batch of tears is entirely unique – like a fingerprint!

The make-up of a tear can give us incredible clues about the emotions that the person shedding them is feeling. I recently saw a beautiful work of art called ‘Topography of Tears’. The artist, Rose-Lynn Fisher, collected over one hundred tear samples, representing moments of regret, loss, laughter and even onion chopping, and examined them under a light microscope. Rose-Lynn was astonished to find that each sample was completely different, to the point that the ‘fingerprint’ of each tear was like its own landscape, from feathery fields to jagged mountain ranges. The irony of this art moving me to tears isn’t lost on me!

Just like Rose’s beautiful work, tears don’t just affect the crier. Tears have been found to reduce aggression. How? The blurred vision that crying results in can prevent a person from engaging in aggressive activities. Aggressive behaviour in people witnessing someone cry is also reduced so it may be an evolutionary advantage to be able to cry at moments that might otherwise end rather more messily.

Let it all out!

Tears are loaded with chemicals and laden with emotion, playing a critical role in our ability to control physiological changes in hormones when experiencing intense feelings. Just like the simple, yet powerful impact of human touch, your tears leave fingerprints wherever they’re shed. So the next time you feel that tell-tale prickle at the back of your eyeballs, it might not feel great at the time and you might be annoyed you can’t stop it from happening but trust me, your body’s knows exactly what it’s doing, so grab a hankie and just let it all out!

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