29 June 2022

The unbreakable pongs of friendship

The Back Page

Smell may be a bigger part of finding and keeping mates than we realised.


You’d like to think you choose your friends based on some higher-level affinities – similar politics, a common regard for Puccini or Boy and Bear, or a hatred of Collingwood.  

It feels slightly indecent, then, to be told that we might be forming these bonds based on smell.  

The Back Page remembers this study from a few years back which found people smelled their hands, seemingly unconsciously, twice as much after shaking hands with a stranger as before.  

It’s disconcertingly similar to the kind of meeting of minds that occurs between dogs in a park.  

Now a new study provides more evidence for the role that similar body smells play when two people “click”.  

The researchers recruited 20 pairs of same-sex friends of both sexes who said they had immediately clicked upon meeting. They “harvested” the subjects’ body odours and compared them in pairs using an electronic nose and real human sniffers. Both types of nose rated the friends’ smells as more similar than those of random dyads.  

To untangle the several potential explanations for this (first, as hypothesised, “this similarity may be related to the root causes of friendship … alternatively, this similarity may somehow be a consequence of long-term friendship, following common body odor-shaping experiences … [or] this similarity may be related to some independent unknown factor and that this same unknown factor may, in turn, be driving friendship”) they then tested whether the sniff test could predict instant friendships.  

They recruited 17 strangers, harvested and eNosed their odours, then put each same-sex pair through a range of interaction tests, including the mirror game (where participants face each other and try to mirror each others’ hand movements) and saying whether or not they believed they had clicked. 

They found the dyads that reported a mututal click “were significantly more chemically similar than dyads who did not report clicking”. 

Unfortunately for those who think the mirror game might be an effective, objective and less socially painful alternative to traditional speed dating, “we did not observe a link between eNose-derived chemical similarity and the quality of mirroring”. 

Among its limitations, the study’s authors note this sizeable one: “Our round-robin study diverged from natural conditions in that participants were not allowed to speak with each other. In natural behaviour, humans use complex language to interact, and it is in this that we are indeed most different from other terrestrial mammals … Thus, the significance of body odour similarity in our paradigm may have been greater than it is in everyday behaviour.” 

To which the Back Page can only say “phew” – there may be room for shared values after all.  

If something gets up your nose, flick it to penny@medicalrepublic.com.au 

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