No matter how tough and resilient we tell ourselves we are, everybody has “those days”–especially those of us who are new to this whole “college” and “independent” thing. The somber combination of drizzling rain, sad songs and heavy-heartedness can turn on the waterworks in a blink of a tear-filled eye, but that’s okay–everyone needs a good cry now and again. But why do we? Why do we cry when we are overwhelmed by emotion, whether it be happy or sad?
Did you know that you’re always crying? Well, sort of: our eyes are always creating basal tears, which help lubricate the cornea and keep out pesky dust specks. We also have reflex tears, which are triggered in response to physical stimuli such as the chemicals that are released when you chop an onion, or when you go to rub your eye after forgetting that you just ate that Chipotle burrito full of jalapeños (I think we’ve all been there). These contain more antibodies to fight off potentially infection-causing microorganisms. Finally, we have our emotional tears, the ones most often accompanied by less than attractive face-reddening, hitched breathing, and, if being brought on by negative emotions, overall hot-messing. Not only are these tears different than basal and reflex tears in their chemical makeup (they contain more protein-based hormones like leucine enkephalin, a natural painkiller), but they actually have unique structures depending on what emotion has brought them on. In 2013, artist Rose-Lynn Fisher decided to use her photography skills and a microscope to capture what different tear stains looked like, from the laughing-until-crying ones to onion-chopping ones to tears of pure grief. The results are stunning (check out the full project here).
So back to the question: why do we cry when our emotions get the better of us? Is there a particular evolutionary advantage to it? Possibly. According to a TED-Ed by Alex Gendler, strong emotions can make us feel out of control, and emotional tears are released (along with the other “hot-mess” physical reactions) to stabilize our thoughts . No one is precisely certain why these tears help, though many scientists believe it may be to try and elicit a sympathetic response from those around us (though I’m sure most of us frequent-flyers have felt the opposite of sympathetic when hearing a baby cry). Crying reveals our vulnerability, notably during our early childhood when we are at our most helpless. Like I mentioned earlier, these tears also contain leucine enkephalin, a stress-induced hormone that is a naturally-occurring painkiller, and may help with physically making us feel better.
So all that’s left to answer is the emotion question–I know that I cry when I’m feeling blue, but what about when I’m overjoyed? According to Neuroscience blogger Jordan Gaines, your hypothalamus cannot tell the difference between emotions–all it knows is that it’s receiving a strong signal from your amygdala, which is responsible for registering your emotions. After the hypothalamus gets this signal, it activates the parasympathetic nervous system, which in turn increases tear production in your tear ducts. So whether it be your wedding day, seeing your loved ones after a long time away, or a death of a beloved pet, you can blame your hypothalamus for that salty stuff that runs down your face and ruins your make-up.