People Befriend People Smelling Like They Do

How your BO and BFF might be interlinked...
28 June 2022

Interview with 

Noam Sobel, Weizmann Institute


A man's nose.


“We sometimes encounter people, even perfect strangers, who begin to interest us at first sight, somehow suddenly, all at once, before a word has been spoken.” - the words of Fyodor Dostoevsky in his novel “Crime and Punishment.” It might have been written in 1866, but it’s still absolutely true today: there are people with whom we feel an instant bond when we meet them. But rather than it being down just - as Dostoevsky suggested - to what they look like, what they smell like might be a hidden part of the formula. A new study has shown that people with the same body odour profiles are much more likely to “click” instantly and become friends. It was an idea hatched by Inbal Ravreby, at the Weizmann Institute in Israel. She works with Noam Sobel, who joined Chris to talk about the work, but from a slightly unusual venue, because Israel’s got strikes going on, just like we have…

Noam - I'm actually hiding behind some building in a pool with my children running around here somewhere because there's a teacher's strike in Israel today. So life has been turned upside down a bit.

Chris - <Laugh> So we've got trains on strike. You've got teachers on strike, but science prevails. We're gonna try and converse all the same and you're hiding behind this cafe. I hope they don't mind. Tell us about this study. The people that you're there at the pool with, do they smell like you?

Noam - I think the chlorine is probably knocking. Everybody's smell out here, but this study is about the fact that people are smelling each other and they're probably making decisions based on that. And so this particular study is decisions of the type of who you would like to befriend or become friends with. Basically it built on two observations. So one is we know for a long time that people are constantly sniffing and smelling themselves. If you just observe people, whether I do that now at the pool or you at, at your radio station or wherever people are constantly smelling themselves. Of course, if you wanna take this to the extreme, in our lab, we call this the "Lev Effect" named after German football coach, Joachim Low - or "lef" depends how you wanna pronounce it - and to those of you who have a spare minute - and this is not for the faint of heart - you can go into YouTube and perform the search "Joachim Low sniff", and you will be amazed! But that aside, we all do this. So, people are constantly sniffing themselves. We also sniff strangers, but we tend to do this in a covert manner. For example, a study from our group demonstrated that often after we shake hands with individuals, the hand that shook then comes to our nose. And the question is, what does this serve? Why do we do this? And what Inbal, the lead author, hypothesised is that we're comparing - at some subconscious level - we're comparing our own odour to other people's odour. And if the odors are the same, then that promotes social interaction. That's good for connecting. So we become friends with people who look like us, with people who have similar values to ours, even with people who have similar patterns of brain activity to ours. So similarity promotes friendship. Maybe similarity promotes friendship in body odour as well!

Chris - So how did you test that then?

Noam - Inbal concentrated on a very particular type of social setting? What she refers to as "click friends". Now, this is something we're all really familiar with from our life. Do you have any person you ever met and, you know, the minute you met, you clicked? Everybody's familiar with this phenomenon, but how did that happen? What was it there that made you click? And Inbal hypothesised that this would be chemistry. So she recruited from around Israel pairs of click friends. And once she identified a cohort of both male and female click friends, she then sampled their body odours.

Chris - But how do you actually smell that, and work out what the smells are that are on the odour profile?

Noam - Right then Inbal carried out two types of experiments. In one, she used the device we call an electronic nose. Now this is a bit deceiving because it's not really a nose, but it's a set of chemical sensors that are supposed to act like a nose. And so she smelled these pairs of body odours with an electronic nose, and then she smelled also just random pairs of people. And she asked whether the electronic nose finds the body odour of click friends to be more similar to each other than just random people. And the answer was a resounding yes, click friends smell more similar than just random pairs of individuals.

Chris - What about if you go the next step and say, "I'm now gonna ask a human to do it."

Noam - And so Inbal did exactly that, and she had cohorts of smellers smell these body odours and rate their similarity. And once again, consistent with the e-nose results, she found that smellers find that click friends - these pairs of people who are friends - smell more similar to each other than just random pairs of people.

Chris - Have you gone a step further, which is to make someone smell different?

Noam - Ah, have you been spying?

Chris - Well, maybe. I've been hanging around your swimming pool! Because, if you could take someone who, you know shouldn't be friends and subvert the smell system by making them smell better, could you do that? Or have you tried that?

Noam - So you, you know, so that's a superb question and, you know, in science jargon, what that means, if a scientist tells you that your question is superb, that means that's just what they're working on now. So yes, we're doing exactly that right now. We found a way to engineer people's body odour. And so we have now formed groups of people that we've engineered to have body odour X and other groups of people that we've engineered to have body odour Y. And we're seeing if the Xs get along together with themselves better than they get along with the Ys!

Chris - Does it work?

Noam - I don't know yet. We're also doing part of it while conducting functional magnetic resonance imaging, or brain imaging. So in other words, we're measuring the brain response while all this is happening, because we also want to identify the mechanism that's underlying all this. But we're doing exactly what you suggested we do. Namely, see if we can engineer a social interaction by engineering body odour.

Chris - Do we sort of do that as a race anyway, because when I get out the shower, I reach for the deodorant tin or I reach for the aftershave or whatever. We all do it. We all distort our natural smell profile a bit don't we?

Noam - I, you know, that's, that's a good question that, that actually we haven't yet really systematically addressed. We don't know. I'll just say one word on that. There's an interesting set of studies from about 20 years ago or 15 years ago. And what they found is that people actually select perfumes that are in a way of function of their own genetic makeup. So even your selection of perfumes is not a random act. It's something that reflects your body chemistry in some way!


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