Why Humans Cry and Its Essential Role
Can you remember the last time you cried? I came close about six months ago. I was watching a real-life video of two men wandering through a lush forest. They suddenly heard a baby crying, and ran to the noise, discovering a newborn abandoned by his mother.
I caught a lump in my throat at the inhumanity of the situation and a child starting life under such circumstances. And if I’m being honest, I also got wrecked by Marley & Me ten years ago, and would again with good movie involving a dog dying.
The role of crying is multidimensional and deeply personal. Understanding why we do it can help you process emotions and better connect with people.
The evolutionary biology of tears
Your eyes often squint when you cry because muscles are putting pressure on lacrimal glands to release tears. These glands are in the upper lateral quadrant of your orbital (lubricating tears are produced in the lower eyelid). You get a lump in your throat when you are about to cry because your body is opening your throat so you can breathe more clearly during the stress response.
Crying evolved to have several purposes. The first is to save us from harm as infants. Babies make noise when crying because it syncs with a visual signal which can go unnoticed. The sound of crying targets an action-oriented portion of the brain and triggers us to notice it more. This is partly why crying babies are so exhausting in public places. You can’t ignore them.
Infant crying also promotes and reinforces caregiving behavior in adults. Tears are the only bodily fluid that doesn’t elicit a revulsion response in a majority of adults.
In a testament to its evolutionary importance, the sound of crying has tremendous crossover recognition with other mammals. Scientists at the University of Winnipeg played the sound of a human baby crying in the woods near a deer. In every case, the deer bounded forward at full speed to inspect the sound. The deer also approached the sound of a crying infant marmot, seal, and domestic cat.