FRIDAY, June 24, 2022 (HealthDay News) — You and your best friend might have your nose to thank for helping you bond, according to a new study.
The researchers found that pairs of friends who just “clicked” on the encounter tended to be more alike, compared to random pairs of strangers. Additionally, a high-tech electronic nose was able to predict, based on body odor, which strangers it would get along with during their first interaction.
The study was small, involving 20 pairs of “clicking” friends, but experts said it highlighted a simple fact: sniffing isn’t just the domain of dogs, and humans use it unconsciously in social interactions.
That’s not to say people choose a lifetime bestie based on scent.
“But it does suggest that olfaction contributes to friendship formation,” said Valentina Parma, a researcher at the Monell Chemical Senses Center in Philadelphia, who reviewed the findings.
Olfactory is the technical term for smell. And compared to our other senses, Parma says, “we don’t tend to think about our noses much.”
After all, she noted, people have their vision and hearing checked regularly. “But,” Parma said, “has a doctor ever checked your sense of smell?”
Still, it’s clear that smell is more important in human bonding than people generally acknowledge. Newborns are a prime example, Parma said. Although their vision is not yet clear, their sense of smell is. And they prefer their mother’s scent, and her mother’s milk, to all others.
There’s also evidence, Parma said, that romantic attraction has an olfactory component — and not just if you like your date’s choice of cologne.
Building a human friendship is much more complicated than sniffing someone out. People have language and take visual cues from facial expressions and body language. People also care about things like personality, values and beliefs, and opinions about movies and music.
But that doesn’t mean we should ignore olfaction in friendshipAccording to Parma: We’ve probably all met someone we’ve had instant “chemistry” with, and the nose may have played a role.
The study – published June 24 in the journal Scientists progress — involved 20 pairs of friends, recruited via social media, where the two agreed they would get along when they met. Each participant gave a body odor sample while wearing a study-provided t-shirt for two consecutive nights – after using study-provided soap and no other products on their body.
The researchers then used an electronic “nose” to analyze T-shirt odors. Overall, they found that each participant’s scent was more similar to that of their click buddy than to that of the other study participants.
A separate experiment involved 17 foreigners. There, the electronic nose was able to predict, with 71% accuracy, what people would immediately gel during non-verbal play: that is, those with more similar smells were more likely to to click.
Why might humans sense a friendship connection based on smell?
body odor is correlated with genetic makeup, and particularly immune function, said lead researcher Inbal Ravreby, a doctoral candidate at the Weizmann Institute of Science in Israel.
Her hypothesis, she says, is that “smelling others allows us to compare between their body odor and our own body odor, and by this we can get an indication of the degree of genetic similarity between us.”
It is possible, Ravreby speculated, that there is an evolutionary advantage to having genetically similar friends, where “by helping friends, we have helped spread our own genes”. But, she added, “alternative explanations are certainly possible.”
It’s hard to tell how much people value their friendship, according to Ravreby. But, she says, “I think the similarity of body odors may play an important role in our tendency to approach or avoid someone, and our tendency to click.”
The findings could have implications beyond understanding human behavior, the researchers say. One question is whether smell-based therapies could help alleviate the social impairments seen in autism spectrum disorders, for example.
Parma agreed that was a possibility. In her own research, she found that when autistic children were exposed to their mother’s scent, they were better able to mimic the actions of others – a social ability that is often impaired in autism.
“I think olfaction isn’t used clinically as much as it could be,” Parma said.
The pandemic has shone a spotlight on olfaction, as many people with COVID lose their sense of smell, at least temporarily. Much of the research attention, Parma said, has been focused on finding treatments for prolonged loss of smell – which currently lacks options.
The Dana Foundation has more on the smell.
SOURCES: Inbal Ravreby, PhD student, Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel; Valentina Parma, PhD, associate director, Monell Chemical Senses Center, Philadelphia; Scientists progressJune 24, 2022, online