With Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon, today we are talking about the surprising results of a study carried out by researchers in neurology, on what the odor of babies would produce in humans. A study published by Advances Sciences, a multidisciplinary scientific journal.
franceinfo: this chemical, emitted by babies, would make women more aggressive… and men calmer?
Mathidlde Fontez: It’s weird, yes. But that’s it. This chemical compound is called hexadecanal. It is a bodily substance, emitted by the skin, breath and stool. She doesn’t smell anything, she doesn’t smell anything.
But animal behavior specialists already knew it: it was measured that it could have an impact on the behavior of certain mammals such as mice, by increasing their aggressiveness. A team of Israeli neurology researchers therefore sought to find out if it had an impact in humans too, and it was not disappointed!
Is the impact strong?
Very strong yes. So much so that it leaves no doubt. Hexadecanal changes our behavior. And what surprised researchers the most is that it modifies it conversely in men and women.
What they did was they subjected 127 participants, about as many men as women, to a classic psychology game. It is an online game that is programmed to be unfair, and in which you can detonate your opponents with different levels of explosives. An annoying game.
And the result is that the women who inhale the substance explode their opponents with an intensity greater than about 18%, compared to the others. When the men, them, explode their opponents with a lower intensity, of 18% too.
Conclusion: hexadecanal increases the aggressiveness of women, and decreases that of men …
This is the first time that we have observed such a strong difference between man and woman, in reaction to a smell. Usually the senses are considered independent of sex. We do not all see the same, but on average there is no noticeable difference between a man and a woman. And the same goes for hearing.
How does this relate to babies?
The report is our exposure to hexadecanal. At what times in life do we smell this body odor the most? When interacting with our loved ones, and in particular children and infants.
We also know that in animals, maternal aggression has a positive impact on the survival of children: mothers are more likely to attack intruders to defend their babies – this behavior even has a name: it is maternal defense behavior. Whereas, conversely, aggression in fathers has a negative impact, because it is often directed towards the offspring themselves.
The difference in sensitivity between man and woman to hexadecanal could therefore be explained: it would have been selected, a long time ago, because it ensures the protection of children, and therefore the survival of the species!