Study finds human tears calm male aggression

A recent study revealed that smell of tears, especially from emotionally provoked women, may have a surprising effect on lowering aggression in males.

The research from the Weizmann Institute of Science in Israel, published in the US science journal PLOS Biology, delved into how tears, not the act of crying itself, contain a chemical signal that could dampen the brain's aggressive behaviour. While previous studies in rodents hinted at similar effects, the recent one focused on understanding if human tears also held a similar power.

Shani Agron, a PhD candidate, led a team of researchers that exposed 25 male participants to tears taken from female volunteers who had viewed sad videos alone. The catch was that, although tears and saline solutions were both transparent and odourless, the male participants were unable to discriminate between them.

The results were amazing. After sniffing the tears, the men, who had played computer games designed to provoke aggression, felt their revenge-seeking behaviour drop significantly. The reduction amounted to a 43.7 percent decrease in aggressive behaviour in males.

Unlike rodents, humans lack a specific organ to detect such odorless chemical signals. Yet, the study found that certain olfactory receptors in human noses responded to the tears, activating specific receptors not stimulated by saline.

Further examination using brain scans revealed that areas associated with aggression, like the prefrontal cortex and anterior insula, showed decreased activity in provoked men who had sniffed tears.

The researchers highlighted the significance of this chemical signaling, especially in non-verbal interactions like between infants and caregivers. The findings suggest that tears might play a crucial role in de-escalating aggression in human interactions, potentially serving as a natural calming signal.

Agron noted, "Crying often happens in close interactions, and the emission of these signals might be more crucial when words can't convey emotions." This study sheds light on the intriguing potential of tears to subdue aggression, offering new insights into human behavior and emotional responses.