Baby scent blocks aggression in men – but triggers it in women

Born yesterday and already starting the drama.

A new study has found that a scent emitted by newborns elicits a surprisingly gendered response.

According to research by scientists at Israel’s Weizmann Institute of Science, the human-made molecule hexadecanal (HEX) – which is found in large amounts on the scalp of babies – triggers aggression in women while by blocking it in men. The discoveries were published this month in the journal Science Advances.

“We have found that HEX does not have a noticeable smell, but that when you sniff it it affects the way you behave towards others – in particular, your aggressive responses towards others,” Dr Eva Mishor , who led the study, said in a press release.

To determine this, the researchers exposed about half of the 130 study participants to HEX while the rest received a check. They then gave test subjects the option of blowing up a playmate with nasty noises of varying intensity. While women exposed to HEX systematically opted for the loudest and most unpleasant noises, men exposed to HEX systematically chose softer noises than their non-HEX-exposed counterparts.

While this may be an unintuitive finding based on societal gender norms, Mishor claimed that gender differentiation has an evolutionary explanation.

“Male aggression often results in aggression towards newborns; Infanticide is a very real phenomenon in the animal kingdom. Meanwhile, female aggression usually results in the defense of the offspring, ”she said. “HEX, it seems, affects men in that there was more social regulation, their aggressiveness was subdued and served as a ‘chill’ signal to them, while in women the regulation was decreasing and this can be seen as a “release” signal.

The molecular mind response is, in a way, babies’ evolutionary strategy of communicating with their parents to increase their chances of survival. “Babies cannot communicate through language, so chemical communication is very important to them,” said Professor Noam Sobel, whose research group led the study. “As a baby, it is in your best interests to make your mother more aggressive and reduce your father’s aggression.”

In addition to the discovery that the smell of HEX affects men differently than women, the study is “among the first” to demonstrate a direct link between the smell of a molecule and human behavior.