we may choose friends based on how they smell

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when it comes to judging other people on their body odour, we may be more like other mammals than we realize, according to a new study.

by maija kappler

published jul 08, 2022

3 minute read

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3 minute read

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we may choose friends based on how they smell

we may choose our friends in part based on their scent, according to a new study. (getty)

our sense of smell might play a bigger part in our relationships than previously believed: a new study published in the journal science advances suggests that people seemed to connect more quickly with other people who had a similar body odour.

“this is not to say that we act like goats or shrews — humans likely rely on other, far more dominant cues in their social decision-making,” the study’s co-author dr. noam sobel said. “nevertheless, our study’s results do suggest that our nose plays a bigger role than previously thought in our choice of friends.”

researchers from the weizmann institute of science in israel studied 20 groups of two friends, all same-sex pairs with non-romantic relationships, who said they became friends very quickly. they collected body odour from both members of the pairs, as well as from two random people, and had 24 volunteers smell them to assess similarities. they smells from both members of the friendship pairs were also compared using an “enose,” an electronic sensing device that can detect specific smells.

both the real humans and the electronic nose found the same thing: the friends in each pair smelled more like one another than the people in the two random pairs.

it might be easy to assume that good friends have these similarities in smell because they have similar backgrounds. but the researchers point out that the similarities in the way these pairs smell “is not explained by race, country of birth, mother tongue, values, level of education, marital status, smoking status, caffeine consumption, chronic health issues, dominant hand, profession, and glasses; and in women, usage of contraceptive pill, regular or irregular periods, and the day of the menstrual cycle.” only similarity in age “was significantly positively correlated” smelling similarly.

still, that didn’t necessarily prove that these pairs were friends because they smelled alike. maybe they smelled alike because they were friends, researchers explained: maybe they had eaten together at the same restaurant, or used the same soap or perfume.

to rule out that possibility, researchers paired up people who were strangers to one another, and had them interact nonverbally: they stood about a foot and a half apart and attempted to mirror one another’s hand movements for two minutes. researchers also used the enose to get detailed smell reads on both people. the two people were then asked to asses how much they liked the other person, and how likely they were to become friends.

they found that the pairs that rated one another most highly were also the pairs that smelled the most similar. when they entered their data into an algorithm, they were able to predict who would get along best, with a 71 per cent accuracy rate.

“we could predict social bonding with an electronic nose,” researchers wrote in the journal article. “we conclude that there is indeed chemistry in social chemistry.”

it’s conceivable, they write, that “perfect strangers may begin to interest us at first sniffs rather than at first sight alone.” it’s often believed that the human sense of smell is weak compared to other animals, particularly other mammals, but previous research has actually disproved that: a 2017 study found that we actually have more sophisticated and developed olfactory bulb than mice and rats. and we may be smelling each other, and others, more than we realize: studies have shown it’s actually quite a common subconscious human act.

the researchers acknowledge that the significance of body odour similarity may be different outside of a lab setting, where humans generally interact with one other in complex ways, including the use of language. still, they say, “we think our results imply that we may also be more like other terrestrial mammals in this respect than we typically appreciate.”