What is it about?
Why do we cry? Even Charles Darwin was puzzled by the purpose of emotional tears, as they didn't seem to serve any useful function besides lubricating the eye. He concluded that tear shedding must have evolved in humans by chance. However, the study now suggests that, just like in rodents, human tears convey a chemical signal that helps reduce aggression. We’ve shown that tears activate olfactory receptors and that they alter aggression-related brain circuits, significantly reducing aggressive behavior.
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Why is it important?
We have answered the very basic question: what is the functional purpose of emotional tears? The findings suggest that tears are a chemical blanket offering protection against aggression – and that this effect is common to rodents and humans, and perhaps other mammals as well.
Perspectives
We think a particular strength of the study is the combination of methods: we used behavioral paradigms, brain imaging, and molecular biology, to study a very basic question in humans, why do we cry? Bridging these levels provides for a powerful tool
Shani Agron
Weizmann Institute of Science
Read the Original
This page is a summary of: A chemical signal in human female tears lowers aggression in males, PLoS Biology, December 2023, PLOS,
DOI: 10.1371/journal.pbio.3002442.
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