Why Do We Cry?

You’re watching a movie. Nothing is happening to you. The character on screen isn’t even real. You know this. And yet something tightens in your chest, your vision blurs, and you’re crying.

About a movie.

About something that never happened, to someone who doesn’t exist.

This is embarrassing and universal. But there’s a more interesting question underneath it: why do tears exist at all? Not the ones from cutting an onion — those make mechanical sense. The other kind. The kind that come from grief, or relief, or watching a dog reunite with its owner after three years.

Why do emotions make water come out of your eyes?

Three Completely Different Kinds of Tears

Your eyes produce three types of tears, and they’re not the same substance.

Basal tears are on your eyes right now. They keep the cornea lubricated and clear. You make about a milliliter of them per day. You’ll never notice them.

Reflex tears are what happens when something irritates your eye — smoke, onion fumes, bright light. Your nervous system detects the chemical and floods the eye to flush it out. Fast, local, automatic.

Emotional tears are different. Not just because of what triggers them, but because of what’s in them. Chemically, they’re not the same fluid.

Emotional tears contain higher concentrations of stress hormones — adrenocorticotropin (ACTH), prolactin — as well as leucine enkephalin, which is a natural painkiller. Your body is, quite literally, excreting stress.

The Dutch psychologist Ad Vingerhoets has spent decades studying crying and his finding is clear: crying is not just a reflex. It’s a regulatory system. Your body uses it to discharge emotional chemicals it doesn’t need anymore.

The Social Signaling Hypothesis

But that only explains part of it. The more interesting question is evolutionary: why tears visible to other people?

Think about what tears actually do to you physically. They blur your vision. They make your face contort. They make a sound. Crying, in other words, is extremely bad for your ability to fight, flee, or appear in control.

Which is exactly the point.

When you cry in front of someone, you are communicating something that words often can’t: I am not a threat. I am not in control. I need something.

Tears signal vulnerability in a way that is genuinely hard to fake — hard enough that we’ve evolved to respond to them. When you see someone cry, your mirror neurons fire. Your threat-detection circuits stand down. The part of your brain that evaluates “is this person dangerous to me?” gets replaced by the part that asks “what do they need?”

Babies cry because their survival literally depends on other people responding. Adults cry because — millions of years later — the circuitry is still there, and it still works.

Why You Feel Worse During, Better After

Here’s the paradox most people notice but can’t explain: crying feels terrible while it’s happening. Your face hurts, your breathing is irregular, you feel out of control. And then, fifteen minutes later, you feel strangely calm.

This is the parasympathetic nervous system doing its job.

During intense crying, your sympathetic nervous system (fight-or-flight) is activated — elevated heart rate, elevated cortisol. After the cry peaks, your body switches over. The parasympathetic system (rest-and-digest) takes over. Heart rate drops. Breathing slows. The stress hormones that were excreted in the tears are gone.

You feel better because you actually are chemically different than you were before. Not metaphorically. The specific molecules have left your body.

Why Fictional Sadness Makes You Cry

Back to the movie.

Your brain’s emotional processing systems don’t perfectly distinguish between real experiences and vividly imagined ones. When you read a novel, your cortex knows it’s fiction. Your amygdala — the part that processes emotional significance — doesn’t always agree. It fires as if the threat is real, as if the loss is real.

But here’s the interesting part: you’re safe. Your prefrontal cortex knows nothing is actually happening to you. So you can feel the full weight of the emotion without the need to act on it. No fight, no flight, no decisions required. Just the feeling, running its full course.

This is, arguably, why fiction exists. It lets you rehearse emotional experiences in a controlled environment. Grief without actual loss. Fear without actual danger. The feeling of watching someone sacrifice themselves for someone they love — without anyone having to sacrifice anything.

The tears are real. The stress hormones are real. The release afterward is real.

The story that caused it doesn’t have to be.

The Thing That Makes Us Different

Here’s the part that should stop you for a second.

Humans are the only animals confirmed to cry emotional tears. Other animals produce basal and reflex tears. Elephants, chimpanzees, and dogs show emotional responses to loss — they clearly feel things. But the evolved mechanism of producing visible emotional tears as a social signal appears to be ours alone.

Whether that means we feel more deeply is unknowable. But it does mean something: we evolved a specific, expensive, visible mechanism for showing that we’re overwhelmed. Our bodies are designed to leak when the pressure gets too high.

That’s not a malfunction.

Next time you cry at something that doesn’t matter — a song, a commercial, a scene you’ve already seen three times — consider what’s actually happening. Your amygdala is treating it as real. Your body is using the moment to discharge something. Your face is broadcasting a signal so old it predates language.

You’re not being irrational.

You’re doing exactly what you were built for.