You may want to get up close and personal with new people’s aromas (pandemic restrictions permitting), as a study has found that people with similar body odors are more likely to hit it off and become friends. The study also found that established friends are more likely to smell alike than random pairs of strangers.
This research was conducted by an electric nose, or eNose, and published in Science Advances. Surprisingly, this technology is not so niche that it was made just for this study – in fact, it is a commercial piece of technology used in many studies. This eNose can map odor similarities and also predict the likelihood of strangers bonding during social interactions.
The scientists sampled the body odor from 20 sets of same-sex nonromantic friends who reported they immediately clicked when they first met.
Same-sex pairings were chosen because males and females generally have discriminable body odor, and we as a species are very good at determining the sex of the odor-maker. Also: “Previous studies showed that heterosexuals tend to be sexually attracted to potential romantic partners with a different body odor.” Inbal Ravreby, lead author of the study, told IFLScience.
“The suggested interpretation is that since body odor reflects genetic makeup, and especially the immune system (human leukocyte antigen), it may be a subconscious mechanism to choose others who are different genetically, which in turn increases the chances of the offsprings to survive. In contrast, friends are highly similar to each other in many aspects such as age, value and personality and even the brain response and the genetic makeup.” Ravreby said.
The scientists sampled the body odors using the eNose. When the data was analyzed, it was revealed that the even when the data was shuffled, the odors were closer in space than those of random pairs.
The team also recruited human “smellers” to sniff out the odors (what a job). They also agreed with the data – this indicates that the eNose could possibly predict (in 71.21 percent of the cases) whether individuals would click early on in social interactions.
These odor donors also played the mirror game, where the pairs had to stand half a meter apart and move their hands as coordinately as possible. This game also allowed the participants to smell each other.
Why have humans evolved to form relationships with those who smell like us? It could be a subconscious mechanism to infer genetic similarity.
“The rationale behind this intuition is that friends are genetically similar to each other more than random dyads [pairings], but people don't sequence each other's genome before deciding whether to be friends or not.” Ravreby told IFLScience.
“So how do they know? My guess is that since body odor is correlated with genetic makeup (and especially with the immune system), smelling others allows us to compare between their body odor and our own body odor, and by that we may have an indication of the degree of genetic similarity between us.” Says Ravreby.
A genetic similarity could give people an evolutionary advantage that is genetically similar to us. So if we help our friends, we could be spreading our own genes.
However, what happens if you cannot smell, or lose the sense of smell through disease?
Well, the findings do seem to correspond with the reports that people with a sudden lack of smell have social impairments. The study also suggests that chemosignalling is altered in people who are on the autism spectrum.
Have you ever heard of friendships where menstrual cycles sync up? We tested whether in the women dyads in our studies (2 and 5) usage of contraceptive pill, regular or irregular periods, and the day of the menstrual cycle could explain our results and we found that they couldn't.” Said Ravreby.
This research team have plenty of plans for the future.
“In the study that we recently started we will manipulate humans' body odor and examine the underlying mechanism. We will test whether when people smell someone with a similar smell to their own (manipulated) body odor they would be more motivated to become friends than when smelling someone with a different body odor.” Ravreby told IFLScience
“This will be during an fMRI scanning, which will enable us to examine whether indeed humans use their own body odor to compare to others' body odor. We hypothesize that when smelling a similar body odor, self brain areas and social brain areas will be activated more than when smelling different body odor. More broadly, I guess many of the big things in life lay on small things that make the difference – these nuances during interactions, which I plan to further study.”
So, instead of smelling roses… go out and smell the people? Your new BFF maybe just around the corner.