Imagine there was an odorless substance that made men less aggressive when they inhaled it but had the opposite effect on women. Sniffing it made women bolder. Would you go online and immediately click “buy”?
There’s no need: Our bodies produce this substance already. Hexadecanal, or HEX, is one of 6,000 volatile chemicals emitted by our body secretions, like tears and sweat, and in HEX’s case, by an infant’s scalp. Chemical signals like HEX fly under our conscious radar while altering our behavior, said Noam Sobel, a professor of neurobiology at Israel’s Weizmann Institute of Science, who calls his lab “very nose-centric.”
Two experiments—recently published in the journal Science Advances by Prof. Sobel, data scientist Eva Mishor and a team of colleagues—revealed that breathing in HEX influences our social behavior, dialing up aggression in women but attenuating it in men.
The authors speculate that HEX is an ancient survival mechanism. Mothers exposed to the chemical signal would be more likely to defend their babies against threats, while fathers who inhale it would likely be less aggressive.
Excited by the finding, Prof. Sobel thinks this is just the beginning of investigating olfaction as a driver of human aggression.
“The next stage is to do this with actual babies’ heads instead of HEX in a jar.”
