It is often said that people who get along immediately although there is a “chemistry”.
Behind this expression perhaps hides a truth, according to a study published in the journal Science Advances on Friday, which concludes that people who share similar body odors are more likely to become friends.
“Non-human land mammals are constantly sniffing each other and, based on that, deciding who are their friends or foes,” write a group of researchers led by Inbal Ravreby at the Weizmann Institute of Science, Israel.
< p>As humans seek out friends who look like them, the team assumed that humans smell to estimate similar body odors and judge their friendly compatibility.
To verify this, they collected samples of friends of the same sex, not having a romantic relationship and saying that they had fallen in love with each other.
They found 20 pairs of acolytes, made up half were men and the other half were women, aged between 22 and 39.
To avoid any odor contamination, the participants had to avoid certain foods and sleep away from their partner and his pets, in a cotton t-shirt provided.
The t-shirts were collected and then analyzed with an electronic nose, a machine for analyzing the chemical composition.
The researchers found that the scents of each pair of friends were generally closer than those of randomly generated pairs of non-friends.
To see if the machine results matched the human perception, the team recruited noses. They had to smell the smells of two friends, and a third smell — and managed to identify the pairs.
Another hypothesis could nevertheless explain this olfactory proximity: the friends spend a lot of time together, and share common factors that influence their smell, such as where they live and what they eat.
The researchers therefore wanted to determine whether smell predicted the friendly compatibility of two people who do not don't know each other.
By recruiting 17 strangers, they found that the similarity of smells predicted a good understanding between the two people in 77% of cases… and, conversely, the lack of alchemy in 68% of cases.