Question: Why do we cry when we feel pain?

Max Jamilly answered on 14 Mar 2018:

That’s a brilliant question. For something so common, we REALLY don’t know the answer. I’ll tell you what we do know about crying and its effects on the body, and then a few theories about what it all means.

Humans aren’t the only animals to have tear ducts. They are one of the immune system’s first lines of defenses, moistening the eyes to keep out dust and other nasty stuff. But humans are (probably?) the only animals to cry when we’re sad or surprised or threatened. When we cry, the sympathetic nervous system is activated and we breathe more deeply. Several different stress hormones are released, which may help us respond better to threatening situations. The actual composition of ‘sad’ tears is different to normal ‘something in my eye’ tears – but we don’t know why.

I think accepted knowledge about crying more or less stops there. But what’s the point of it? It could be a group behaviour that has evolved over time, a way of signalling to relatives that we need to be looked after. Maybe it prepares us to deal with a stressful situation or actually helps us control our mood. I looked online and found some more crazy theories: maybe it has something to do with helping mothers find lost offspring or it helps make attackers less aggressive and more sympathetic. One scientist even thinks that crying is connected to smoky fires lit when our ancestors buried their dead (but I don’t think that’s very likely!).

It’s incredible how little we still know about some of the stuff our bodies do all the time. Maybe you can become a scientist and help solve mysteries like this one? 🙂