making men & women smell a chemical found in mice, on skin & in poo makes men a bit less aggressive & women a bit more aggressive in deliberately-annoying computer games. no one but the authors or journalists seems to know why.  

original article: Mishor et al., 2021 (Science Advances), reported in: The Scientist by Chloe Tenn on 22nd November 2021 & The Daily Mail by Johnathan Chadwick on 19th November 2021 image source

this story was in episode 22 #skin #breath #faeces #brain #aggression #men

the error bar says

the online science platform, the journal Science & the Daily Mail all lead with the news that the smell of babies makes men less aggressive & women more aggressive.

you'd expect, then, that the reported study involved men & women smelling babies. it didn't.

it's closing time at the error bar, but do drop in next t...


eight & a half minutes?

i'm done.

alright, alright, i'll think of something...

what the researchers actually did was use a synthetic organic molecule called hexadecanal, or HEX, in liquid form. HEX was first found to be emitted by mice.

by mice.

but there are similar-looking chemicals in humans which may, as in mice, play a role in social interaction. HEX is found in human skin, faeces, breath & saliva.

the researchers asked 127 people to sniff HEX or an inert control smell, then to play some aggression-rousing computer games with virtual opponents.

the scientists measured how much the players chose to punish their annoying virtual opponents. after sniffing HEX men decreased their punishments, while women increased them.

some more people were put into a brain scanner where sniffing the HEX chemical provoked more activity in the angular gyrus - an important part of the brain involved in language, social signals, movement, tool use, sniffing babies' heads & lots more.

males & females showed different patterns of brain activity connecting with the angular gyrus. these connections were interpreted in terms of the social significance of the annoying computer game.

some extra data collected at another laboratory, showed that babies excrete HEX from their heads. this amazing finding confirms that babies are, in fact, human.

the discovery that babies are human led the authors to propose an astonishing hypothesis:

the smell of HEX makes men LESS aggressive so that they don't kill babies.


the smell of HEX makes women MORE aggressive so that they can defend babies from (male) attack.

yeah, that sounds fine.

do babies heads make men calm down?


this paper has nothing to do with babies' heads. remember: the natural version of the synthetic chemical is found in mice, many other animals & in human skin, breath, saliva & faeces. yes: faeces. maybe smelling poo calms men down? we may never know.

having dealt with the baby red herring & the nonsense, sexist, post-hoc, just-so story about why men constantly need to be stopped from killing babies, let's look at the data.

along with the aggression findings, the men in the study also found the smell stimulus 'less intense' than women, & these ratings became more extreme as the experiment progressed. this finding could partly explain the aggression ratings, assuming that intense smells make people aggressive.

but apart from that, i am ashamed to admit that i did not find anything so wrong in this paper. if you can get past the ridiculous confirmation-biased evolutionary-psychology bullshit that men want to kill babies & women protect them - which i can't - then this seems a fair study.

large sample sizes, clear presentation of methods & data, sensible-sounding analyses, mostly good stats. indeed, this paper is so acceptable that it really winds me up. i can just see the red mist coming down over my eyes, the blood boiling in my veins & all i can think about is going out to kill some babies.

wait, here's my old pants. [deep breath in]... ahh, it really works.


anything mammal will do


The Scientist: fair - scientific story mostly intact

The Daily Mail: fair - scientific story mostly intact