Why Do We Cry?

There are many reasons humans cry. CREDIT: Dreamstime. View full size image

Any parent cradling an inconsolable infant at 3 a.m. will tell you that tears are not always the clearest mode of communication. Indeed, expressing distress is but one part of the sob story.

• Basal tears (which flow continuously from the lacrimal glands) clean and lubricate the eye, making vision possible.
• Reflex tears clear the eye of irritants produced by, say, onion-slicing.
• Psychic or emotional tears are the complicated ones produced by babies and adults alike.

Believed unique to humans, emotional tears carry certain hormones and other proteins — produced during periods of stress — out of the body, which may explain the cathartic effect of "a good cry." But if the body is attempting to weep its waste away, tears are woefully ineffective; most get reabsorbed by the body. And none of this helps determine whether baby just needs to burp.

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