Hexadecanal - Body odour smell effects in men and women

[ArabellaScott]

Found this fascinating:

'A chemical that is sometimes emitted from human skin, breath and faeces has no detectable smell, but it appears to influence people’s behaviour, with men becoming calmer and women becoming more aggressive.'

'“It’s below the threshold of conscious awareness, yet hexadecanal apparently influences the behaviour of males and females differently,” says de Groot. “These are really striking effects [that underline] the fact that just because we are not aware of it doesn’t mean it doesn’t strongly affect us.”'

www.newscientist.com/article/2298435-body-odour-chemical-makes-men-calmer-but-women-more-aggressive/

The original study is available here:

www.science.org/doi/10.1126/sciadv.abg1530

Oh, I only just noticed this bit in the study itself:

'In summary, babies emit HEX from their head. This is expected to trigger aggression in women but block aggression in men, and both of these impacts are expected to increase baby survival.'

Wow, they should start putting that in perfume.

Or possibly the water supply.

'In summary, babies emit HEX from their head. This is expected to trigger aggression in women but block aggression in men, and both of these impacts are expected to increase baby survival.'

Interesting. The aggression I felt was never directed AT my babies though, only at anything that threatened them. When everything’s functioning as it’s meant to, the human body is an astonishing thing.

Basically, don't try to get between a woman and her baby.😂

Omg I often say to new mums on here " pls sniff baby's head for me" cos there is nothing like a new baby's head smell, is there (apart from puppy biscuity ears?)
Wow.

That is fascinating ArabellaScott, but do you know why it is that when the mother acts more aggressive when the baby emits that smell her more aggressive behaviour would help the baby survive?

Does the baby emit that smell under certain circumstances, or all the time?

If all the time, maybe that helps the mother go into protective tiger mode, and the father, or men around, behave more gently.

On another note it shows how the biological difference between men and women in their reactions to this smell creates different social beings.

It mentioned the trial was conducted with men and women who were not trans. I wonder if trans people who have been taking x sex hormones would have behaved differently?

Ooh that's fascinating!

This caught my eye www.thetimes.co.uk/article/nervous-women-can-smell-it-on-you-kvcntww3h Sorry I can’t do a share token.

Is that sweet baby smell Hex?

Yes, the aggression has to go to anything threatening the baby, not the baby.

But maybe that’s why mother and baby feel like one being.

"has no detectable smell"
"is that baby smell hex"

Cracked me up

And yes to putting it in the water!

Moveahoy, I had forgotten it is undetectable!

I don't know if it's the sweet baby smell - this bit says its found in feces:

'The sex dimorphism in our behavioral and brain results dovetails with previous findings obtained using functional brain imaging (48) and EEG (15) to depict a level of functional brain sex dimorphism in response to social odors that is not matched by any other sensory stimulus that we are aware of. Human functional brain responses to basic auditory and visual cues are generally nondissociable by sex (49), yet here, we could use them alone to discriminate men from women at 79.6% accuracy. '

'This begs the question: what behavioral setting could underlie selection for a body volatile that increases aggression in women but decreases it in men? Or in other words, what could be the ecological relevance of these results? In this respect, we call attention to the setting of infant rearing. Parents across cultures are encouraged to sniff their babies (50), an action that activates brain reward circuits in women (51). Our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers. Whereas maternal aggression has a direct positive impact on offspring survival in the animal world (52), paternal aggression has a negative impact on offspring survival (53). This is because maternal aggression (also termed maternal defense behavior) is typically directed at intruders, yet paternal aggression, and more so nonpaternal male aggression, is often directed at the offspring themselves (54, 55). If babies had a mechanism at their disposal that increased aggression in women but decreased it in men, this would likely increase their survival. With the hypothesis in mind that HEX provides babies with exactly such a mechanism, we first note that infant rearing is the one social setting where humans have extensive exposure to conspecific feces, a rich source of HEX'

(my emphasis)

That is the most interesting information I’ve heard in a long time, ArabellaScott.

@Toseland

This caught my eye www.thetimes.co.uk/article/nervous-women-can-smell-it-on-you-kvcntww3h Sorry I can’t do a share token.

Interesting, thanks!

I'd like to know what other subconscious 'social chemicals' we may be affected by, and what effect they have.

So it seems from that that the sweet baby smell is a lure to get people to sniffing closer and more often so as to get whiffs of Hex.

And the smell of baby poo is important in terms of evolution.

Sorry. It's late. 'Subconsciously sensed'.

Get men to change more nappies, is the moral of the story.

How true

So that expression 'hurling shit' means, if you fling it at a man, he'll smile and if you fling it at a woman, she's likely to fling it back

Back in Elizabethan times they used to put baby poo in perfume. (Source: I read that as a child and it stayed in
my brain.) Maybe that wasn’t as insane as it sounds?

I do remember seeing in a BBC documentary years ago something about fathers of newborn babies having lower testosterone levels, presumably to minimise the risk of becoming aggressive towards the baby.

I would be so interested to know what happens when people have been having x sex hormones.
(The study specifically excluded trans people)