Quirks & Quarks

Why do we cry when we are sad?

The exact reasons why we cry are not fully understood but there are social and biological explanations

This long studied question probably comes down to the human need for attachment.

The exact reasons why we cry are not fully understood, but are thought to have social and biological elements (WenbinDu / Shutterstock)

This week's Question comes from 13 year old Kemiee Kasas in Winnipeg, who asks:

What is the scientific reason for why you cry when you are sad?

Roger McIntyre, a professor of psychiatry and pharmacology at the University of Toronto says this question has stumped scientists for a very long time. Philosophers as far back as the ancient Greek Hippocrates have debated this question. He says the prevailing view today is that crying is thought have a ociobiological explanation.

Thius suggests we cry for the purpose of expressing a want or need to attach, which is an important survival mechanism. Perhaps we are in distress and seek cohesion and engagement with others.

Biologically, there is evidence to show that when you cry you release attachment hormones, like oxytocin. Naturally occurring opioids, which are important for pain relief, are also released when we cry. 

Why our eyes become red and wet when we cry likely has to do with the way eyes are key to how we make connections and communicate non-verbally with others. This is especially important In infancy, as our eyes are the primary way in which we attach to care-givers.



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