We cry when we’re happy, sad, laughing, sobbing. It happens all the time and we just don’t question it.
But, if we stop and think about it, crying as a concept is weird: little droplets of water build up and make their way out of little holes in our eyes just because something upsets us.
Is there a biological reason why we cry? Does it serve a purpose other than making our eyes feel less like sandpaper and washing our cheeks for us?
I turned to my trusty friend Google for the answer.
Apparently, crying doesn’t just happen when we’re emotional. There are actually three different kinds of tears:
Basal tears: they constantly lubricate our eyes and stop them from drying out.
Reflex tears: these tears act in response to an irritant like onions or dust. Onion fumes, for example, trigger the release of hormones in the brain which then sets off a gland response in our eyelids making us cry to get rid of the irritant.
Emotional tears: the kind we shed when watching a sad movie or during a break up.
The interesting thing about emotional tears, is that they’re exclusive to humans. There are a couple of theories as to why this is.
The first theory suggests that emotional tears act as a visual communicator – they signal our genuine sadness or distress to others which makes them more likely to treat us kindly.
From an evolutionary perspective, crying strengthens our bonds with those around us by making us seem more genuine and therefore likeable, increasing our chance of survival.
But what about tears of joy? The same logic can be applied, but there’s also another theory: we cry to literally shed our stress.
The composition of emotional tears vs reflect tears are different. Emotional tears have more ACTH hormones in them than reflex tears which are mostly water. ACTH hormones are stress hormones, so the logic follows: the more we cry the more stress chemicals we release.
But the research here is limited and not yet conclusive. Still, it totally makes sense why I cry when I have a million things to do and I’m exhausted.
So there you have it friends – a quick science lesson for you. Turns out you can learn something new every day after all.