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Piggyback | Sep 16 2002

I don’t know what tears are for. Or rather, I do know; I just don’t know why they take the form they do.

Laughter consists of sound, mostly. Sound and a kind of convulsion. Why does crying include this extra thing?

I am not a biologist (ahem), but it would seem that crying and tearing (I mean the kind of tearing caused by irritants in the eye) share the same underlying mechanism. This would make evolutionary sense. Why develop a new mechanism when you can piggyback on another?

Tearing, I’m certain, came first. I say this because humans are the only animals that cry; the rest merely tear. This includes apes of course, which means that crying developed after apes evolved into humans, which means that tearing preceded crying, which is what I just said.

But to back up a bit. I’m aware that certain mammals get sad (dogs, for example) and that some even vocalize that sadness. None, however, cry. Only humans. Why is this?

I wonder if it’s about the display of emotion. Could there be an advantage, an evolutionary purpose, in exposing one’s pain and grief?

Unless one is an infant, I rather doubt this. Crying reveals vulnerability, and vulnerability, um, leaves one vulnerable. Moreover, crying is debilitating; a person can barely stand while crying, let alone run or fight.

But anyway the question is not about the purpose of crying (one must merely cry once to know this), but rather why tears are part of the package. This I don’t know.

I have a guess, though, which I only just thought of. It’s because tears are so difficult to fake. This sort of follows from my thought about emotional display. We tear when we cry so that others can tell we’re not faking it.

A gentle reminder, most likely unnecessary by this point: I don’t know what the fuck I’m talking about.