24 November 2021

Happiness is the smell of a new baby

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Everybody loves to sniff a newborn.

Well, the top of their heads, at least. Your mileage may vary with the rest of them.

According to a study from the Weizmann Institute of Science, this bub bouquet isn’t just a happy byproduct of the miracle of birth. Rather, it serves a critical evolutionary purpose: brainwashing their parents.

Researchers noticed that the molecule hexadecanal (HEX) is abundant on human baby scalps. HEX has been shown to act as a “social buffering chemosignalling agent,” reducing stress in mice when excreted by their fellow cage-mates.

Using two validated scientific methods for gauging aggressive behaviour, the researchers tested whether HEX had a similar effect on aggression and associated brain mechanisms in humans. They found that while participants who were exposed to HEX exhibited different behaviours from those who were not exposed to it, the results were inconsistent.

Until they took sex into account.

Dividing the results along male/female lines revealed that each cohort responded to HEX differently. While male participants displayed the expected decreased aggression, females’ aggression increased.

Further investigation via fMRI scans showed that HEX activated the left angular gyrus, an area of the brain implicated in the integration of social cues. However, the way that it “talked” to other areas was dependent on sex, triggering increased social regulation of behaviour in men while effectively telling women to “Go off”.

Dr Eva Mishor provides a possible evolutionary explanation: “Male aggression translates many times into aggression toward newborns; infanticide is a very real phenomenon in the animal kingdom. Meanwhile, female aggression usually translates into defending offspring.”

It makes sense that babies would need some non-physical, non-verbal way to control their environment. Unfortunately, they seem to lose interest in keeping dad calm by around the age of two.

If you smell something calming, send a non-aggressive email to felicity@medicalrepublic.com.au

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