It’s often said that the reason people love each other right away is because they share chemistry. That statement may be literally true, according to a new study published in the paper Friday. Science Advancesresult pointing to the fact that people with similar body odor get along better as friends.

“Non-human land mammals constantly sniff each other and decide who is friend or foe based on that,” wrote a group of researchers led by Inbal Ravreby of the Weizmann Institute of Science in Israel.

body odor

Knowing that people are looking for friends who look like them, the team hypothesized that people could smell themselves and others to subconsciously predict similarities in body odor and assess their compatibility.

To find out, they collected samples of same-sex peers with no romantic interest who described their relationship as click-at-first-sight or, as the study describes, “when a sense of friendship precedes extensive biographical information.” exchanged.”

After an extensive search, they found 20 couples, half female and half male, aged between 22 and 39.

To prevent external factors from affecting or contaminating the tests, all participants had to follow a strict protocol that included avoiding spicy foods, sleeping in cotton T-shirts, and staying away from their spouses or pets.

The liners were collected in sealed bags and tested with an electronic nose, a device equipped with sensors that analyze chemical compositions. The researchers found that the olfactory signatures of “friends at first sight” were statistically closer to matching than non-friends.

To assess whether the electronic nose results faithfully replicated human perception, the team recruited human sniffers and designed a series of tests to verify the validity of their results.

In one of these tests, for example, volunteers were presented with three scents: two from a compatible pair and one from a non-compatible pair. They successfully identified their peers and rejected the misfits.

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The scent also predicts friendships.

These results seem to support the hypothesis that similar odors can lead to friendship, but an alternative explanation is that people who were friends spent a lot of time together and had experiences shaped by similar body odors, such as where they lived or what they did. what are they eating?

To reveal these two possibilities, the team devised another test to see if scent was a successful predictor of clicks for two people who had never met.

To do this, they summoned 17 strangers and had them interact with each other in a test called the Mirror Game, which consists of standing half a meter apart so they can subconsciously smell each other. They were asked to make gestures and other hand gestures for two minutes without speaking to each other.

The chemical similarity in their scent tested by the electronic nose successfully predicted matches in 77% of cases, and also predicted that none of them would click in 68% of cases.

And of course, the closer people’s scents were, the more they tended to report that they liked each other, understood each other, and felt more chemistry.

similarities

In summary, the study result “suggests that clicking same-sex friends has more of a similar smell than would have been expected by chance,” the team said.

The team wrote that humans, unlike other land mammals, use complex languages ​​to interact, so the effects of smell under laboratory conditions may be magnified compared to how important they can be in real life.

“However, we think our results imply that we may be more similar to other terrestrial mammals than is commonly believed.”