People maintain polite myths that we’re not constantly smelling each other. Despite our efforts to the contrary, we all have our own scents, pleasing and less so, and if we are like other terrestrial mammals, our special scent may mean something to our fellow human beings.
Some of these, such as the rick of someone who hasn’t bathed all month, or the distinctive whiff of a small child pretending that they just didn’t fill their diapers, are self-explanatory. But scientists who study human odors, or your sense of smell, are surprised that molecules that float from our skin can be registered at some subconscious level in the noses and brains of people around us. Are they carrying a message that we use in our decisions without understanding? Could it be that we don’t like who we are and who we don’t like to spend time with?
In fact, in a small study published Wednesday in the journal Science Advances, researchers investigating a pair of friends whose friendships “clicked” from the start, found curious evidence that each person’s body odor was higher than expected from their friend. And when the researchers found a pair of strangers playing a game together, their body odor predicted whether they felt they had a good connection.
There are many reasons that make friends with people, how, when or where we meet a new person. But perhaps one thing we take for granted, researchers suggest, is how they smell.
Scientists who have studied friendship have found that friends have more in common than strangers – not just age and hobbies, but also genetics, the type of brain activity and appearance. Inbal Ravrebi, a graduate student in the lab at Noam Sobel, a fragrance researcher at Israel’s Weizmann Institute of Science, was intrigued, especially by the quick friendship, which seemed to be made in an instant, with an olfactory element – whether people picked on the match in their scent.
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He recruited 20 pairs of so-called Click friends, both of whom thus marked their friendship. He then introduces them through a common approach to the study of human body odor: Stop eating foods like onions and garlic, which affect body odor, for a few days. Turn off after-shave and deodorant. Take a bath with an odorless soap provided by the lab. Then wear a fresh, clean, lab-provided T-shirt and sleep in it so that it is good and smelly, before handing it over to scientists for review.
Mrs. Ravrebi and her colleagues used an electronic nose to evaluate the volatile substances from each T-shirt, and 25 of their volunteers also assessed the odor match. They were curious to know that, in fact, the smells of friends were more similar to each other than to strangers. This may mean that the smell was one of the things they took in as soon as their relationship started.
“It’s very possible that at least some of them used perfume when they met,” Mrs. Ravrebi speculated. “But it did not mask the similarities between them.”
However, there are many reasons why friends may smell the same – eating in the same restaurant, living the same lifestyle, etc. – making it difficult to say whether the smell or the basis of the relationship came first. To investigate this, the researchers had 132 strangers, all of whom first stabbed a T-shirt, came to the lab to play a mirroring game. The pair of subjects stood close to each other and had to imitate each other’s motion as they moved. Later, they filled out questions about whether they felt connected to their partners.
The similarity of their scents, surprisingly, predicted that both felt that there was a positive connection 71 percent of the time. This finding suggests that smelling like our own makes us feel good. When we meet new people it can be a thing where they have grown up and whether they like science fiction or sports. But Dr. Sobel warns that if that is the case, it is just one of many reasons.
The Covid epidemic has so far reduced further research using this design by Mrs. Ravrebi and colleagues; It’s hard to set the test that strangers come close enough to smell each other.
But now, the team is searching to change people’s body odor to see if things are made to smell similarly. If smell is related to their behavior, this is further evidence that, like other terrestrial mammals, we can draw on our sense of smell to help us make decisions.
There are many mysteries for them and other researchers to study about how our personal perfumes, in all their complexity, interact with our personal lives. Every puff of air can say more than you know.
“If you think of the bouquet as body odor, it’s at least 6,000 molecules,” Dr. Sobel said. “There are 6,000 here that we already know – that’s probably a lot more.”