Did you know that humans are the only animals that cry? It’s true. While other animals’ eyes may produce tears in response to an infection or irritant in the eye, we are the only ones who cry as a result of emotion.
Three Types of Tears
Humans actually produce 3 types of tears which have different compositions based on the job they perform.
- Basal tears keep your eyes moist and protect them. They are constantly being released into each of your eyes in tiny amounts and are dispersed over their entire surfaces when you blink.
- Reflex tears are the type that are released in response to something irritating like dust.
- Emotional tears are produced and released when you experience a strong feeling such as sadness or joy. Even physical pain can bring on this type of tear.
Emotional Tears and How They’re Triggered
When you have a strong feeling or experience physical pain, your nervous system may react partially by emitting the chemical acetylcholine. This is what can trigger your tear ducts to produce tears and lead to crying.
Why Do People Cry?
Now that we know that humans are the only species that cries due to emotions, the obvious question is: why?
Scientists have studied this, and they believe that crying is a way for us to add additional levels to our communication with others. Simply having a sad face may not be enough to convey, for instance, that you are overwhelmingly upset. In fact, your facial expressions may be misinterpreted as other emotions. However, when you add tears, others may more easily be able to decipher how you’re feeling.
Tears may help promote empathy in others and trigger them to wish to help you. From an evolutionary standpoint, developing the ability to cry as a result of emotion may have helped humans survive and thrive in groups.
Crying May Help Relieve Stress
Emotional tears, unlike basal or lacrimal ones, contain a high concentration of ACTH, a chemical related to stress. Many scientists believe that crying may be a way to help rid our bodies of these stress hormones so we can actually feel better.
A study was done recently to determine whether crying makes people feel better (Asmir Gračanin, 2015). After having their moods evaluated, people were asked to watch an emotional movie. Afterwards, their moods were evaluated again 3 times: immediately after the show, 20 minutes later, and 90 minutes later.
The people who cried during the movie felt worse immediately afterward than those who didn’t cry. However, by the 90-minute mark, the criers felt better than the non-criers and even better than they themselves had before the emotional movie was shown. So, though crying may make people feel worse in the short term, it seems to help us feel better over the long term.
Remember, if you feel like having a good cry, go ahead and indulge. It may remove stress hormones from your body, help others understand you better, and ultimately aid you in dealing with things more positively.
- Asmir Gračanin, J. J. (2015, Dec.). Why crying does and sometimes does not seem to alleviate mood: a quasi-experimental study. Retrieved from Springer Link: DOI: 10.1007/s11031-015-9507-9.