People who share the same scent are more likely to form a friendship

The research was done with friends from so-called at first sight, where the chemistry is instant. Westend61 (Getty Images/Westend61)

Smelling is a social need for most animals.

It helps determine who is friend or foe, detect receptivity for reproduction or allows mothers to locate their young.

But among humans, smell is the least valued of the five senses.

However, it performs functions, some vital, and almost always unconsciously.

The smell of tears, for example, appears to be associated with reduced testosterone levels in men.

Now, Israeli neuroscientists have found that friends share a scent and that people who smell different are less likely to form a new friendship.

If a person were forced to do without one of the five senses, they would probably choose smell.

After playing an essential role as a link between newborns and their mothers (and fathers), smelling seems to be confined to the world of conscious aromas (food, perfume, rubbish...). However, recent studies have shown that joy or sadness smell differently or even that humans can infer or provoke emotional states in others by smelling them.

On this basis, researchers from the Weizmann Institute of Sciences (Israel), have investigated the relationship between smell and friendship.

His starting hypothesis was that friends have a similar odor profile.

The research, published in the scientific journal Science Advances, is based on a series of experiments with pairs of friends.

They used an electronic nose equipped with sensors capable of detecting and classifying the chemical composition of volatiles to create a profile of 40 people who formed dyads.

His scent also had to be smelled by human sniffers.

In both experiments, they observed that the friends had more similar profiles with each other than with the other participants.

"We recruited twenty pairs of friends at first sight because they present something distinctive: people immediately know if they connected or not"

Inbal Ravreby, researcher at the Weizmann Institute of Sciences (Israel)

But smelling the same could be due to friends spending more time together, eating the same thing or having experiences or in common spaces.

That is to say, the friendship and the environment would cause them to smell in a similar way and not that it is the aromas that forge the relationship.

To determine which came first, the study authors already took this risk into account when designing their research: They only selected friends who had a crush, those friendships that are formed almost from the first moment.

Inbal Ravreby, the main author of the study, explains it: "We recruited twenty couples of friends at first sight because they present something distinctive: people immediately know if they connected or not, unlike friendship in general, where the limits between a friend and an acquaintance, for example, can be ambiguous.”

But,

Even more important to Ravreby was "to understand if there really was that chemistry."

And the smell is nothing but chemical volatiles.

"For this reason, friendship at first sight seemed like a great candidate, as people immediately feel chemistry with someone, in a way that sometimes feels almost magical and inexplicable," she concludes.

So they turned it around in the last experiment.

This time they selected dozens of people who did not know each other.

They had to play a version of the mirror game, in which one has to repeat what the other does.

Used in psychology, it is a way to measure the best or worst connection in social interactions.

They saw that those people who scored the best in the game also shared an odor profile.

In fact, the electronic nose was able to guess 71% of which pairs worked best.

This would show that body odor contains information that makes it possible to predict the quality of social interactions between strangers.

Does this mean that people with the most different smells can't be friends?

“Our results suggest that they are less likely to connect with each other, to become an instant friendship.

However, we do not know what happens with friendships in general.

That said, we've found that body odor similarity predicts many aspects of the quality of social interaction, such as liking, mutual understanding, a sense of chemistry, or a willingness to become friends.

Following these results, I hypothesize that, indeed, people who smell very differently are less likely to be friends.

But more studies are needed to answer the question empirically”, says Ravreby.

Smell plays a relevant role in agricultural and hunter-gatherer societies, where they have developed vocabularies for what are called

smells ”

Gün R. Semin, director of the William James Center for Research at ISPA – Instituto Universitario (Lisbon)

Professor Noam Sobel, head of the Smell Research Group at Weizmann and senior author of the research, immediately warns that "this does not mean that we are like goats or shrews, humans depend on other signals that are probably much more dominant in their social decision making.

In a note he concludes: "However, these results imply that our nose is playing a more important role than we had assumed in decisions such as whom to befriend."

These mechanisms always work on the subconscious plane.

Gün R. Semin, director of the William James Center for Research at ISPA – University Institute (Lisbon), has spent years studying the communication of human emotions through chemical signals, such as those that make up any scent.

Semin, who was not involved in this research, acknowledges that smell is an underappreciated sense, but not everywhere.

“It is like that in several of the industrialized cultures.

It is largely due to the dominance of vision and the cultural insignificance of odors in adaptation to our industrialized societies.

However, scent does play a relevant role in agricultural and hunter-gatherer societies, where they have developed vocabularies for what are called

scents ”,

comment.

But, he adds: “As far as I know, there is no vocabulary for

scents .

In fact, in all the studies we've done with these odors, most participants don't even perceive human odor, even though there is psychophysiological and behavioral evidence that they systematically affect people."

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