Experiment with worn shirts
Those who are close friends smell similar
06/27/2022, 08:51 am
You know “love at first sight” in couples, but there are also friendships that develop spontaneously, so-called “click friendships”. And people who like each other from the first moment often have a similar body odor, an Israeli study finds.
In the case of spontaneous friendships, a similar body odor in both partners apparently plays an important role. This is suggested by the results of an Israeli research team in the journal Science Advances. Using chemical measurements and also using human sniffers, they showed that, on average, close friends have a more similar smell than strangers. The group led by Noam Sobel from the Weizmann Institute in Rehovot was even able to use the body odor of two unknown people to predict whether they were on the same wavelength in a kind of game experiment.
Previous studies had shown that people who resemble each other are more likely to be friends. Similarity can refer to more obvious characteristics such as age, level of education, religion and physical appearance. But more complex characteristics such as personality, values or even similarities in the genetic material also play a role.
Friendships can also “click”.
The researchers led by Sobel assume that similarities in body odor also play a role in friendships. Accordingly, the effect should be particularly large in spontaneously formed friendships – because here the first impression counts. The researchers speak of “click friendships”. In the case of connections that have developed over a longer period of time, on the other hand, other factors such as one’s own biography are likely to play a greater role.
It has long been known that smell plays a role in interpersonal relationships. Smells can influence a person’s behavior, but the other way around, they can also reveal something about their state of mind.
The researchers focused on non-romantic relationships between two partners of the same sex. 20 pairs of friends took part in the experiments and clicked immediately after they first met. The 40 test subjects had to submit samples in the form of worn T-shirts, on which only their own body odor should cling if possible. They had slept in the shirts for two nights after showering with unscented soap.
An electronic nose – a device with sensors – then analyzed the smell of the T-shirts for various chemical components. A kind of odor profile was created for each test person. The comparison showed that the odor profiles of close friends were significantly more similar than those of randomly selected odor samples. Experiments with people who smelled the samples and judged them according to certain criteria and similarity came to a similar conclusion.
Friendship because of smell – or smell because of similar environment?
But is the similar smell actually a criterion for friendship? Or does friendship lead to similar body odors because you eat similar things or live in the same area? To get to the bottom of this question, the researchers conducted another experiment with 17 subjects who were strangers to each other. They also submitted odor samples that were analyzed by the electronic nose.
In different constellations, the test subjects performed a kind of mirror image game in which they stood opposite one another and were asked to imitate each other’s hand movements without speaking to one another. The subjects were then asked to judge whether they had clicked with their game partner. And lo and behold: with partners who felt they harmonized well during the game, the odor profiles were more similar on average. The researchers were even able to create a kind of model that can use the odor profiles of two test subjects to predict their connection during the game.
The researchers concede that it is possible that there is no direct connection between body odor and friendship, but that an unknown third factor influences both elements. However, the effects found in the experiments could not be explained by other factors such as country of birth, level of education, chronic illnesses or use of the contraceptive pill.
The researchers did not examine the mechanisms in the brain behind the phenomenon. But they suspect that everyone subconsciously perceives their own body odor as a kind of blueprint and compares it with other odors.