If you can smell well, you have more friends

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Chrissi Kelly no longer felt like herself. The US archaeologist living in Great Britain lost her sense of smell in 2012 after a viral infection. She felt like she was adrift, detached from the rest of the world.

The sense of smell, she says, is something that connects us to nature and our families, and without it we cannot fully participate in daily life. She missed the social component of scents: the deep joy of hugging a loved one and absorbing their personal aroma. “Life without a sense of smell was deeply confusing to me.”

Study: Those who can smell well have more friends

Kelly was so affected by what happened to her that she founded the British charity AbScent, which aims to help people with loss of smell. New findings confirm Kelly’s belief that the sense of smell is part of a person’s identity.

In 2023, a European research team found that we smell other people’s fears and worries and are infected by them. Another study from China showed that people with a better sense of smell have more friends. “We see all sorts of behavioral effects,” says Shani Agron, a neurobiologist at the Weizmann Institute of Science in Israel.

People have long underestimated their noses. Darwin, for example, claimed that the sense of smell was of “extremely little use” to humans. According to Bettina Pause, a biological psychologist at Heinrich Heine University Düsseldorf, one reason for this could be that the social sense of smell lies outside of our conscious awareness. According to her, you just notice that the way your body feels changes.

Mothers and babies recognize each other by smell after just a few minutes

Nevertheless, humans seem to be quite capable of detecting someone else’s body odor. An Israeli research group observed that people reflexively smell their right hand more than twice as often after shaking hands with people of the same gender than before greeting them.

By sniffing the body odor of the people around us, we pick up a whole range of information: We recognize relatives.

In an Israeli study from the 1980s, for example, most new mothers were able to recognize their baby by smell after just ten minutes with their baby, and conversely, newborns also recognize their mother. We can also sniff out who is genetically related: identical twins can be identified by their body odor, even if they live apart.

We prefer people who smell similar to us as friends

Last but not least, we unconsciously check with our nose who we want to be friends with – we prefer those people who are similar to us genetically and in terms of body odor.

In a 2022 study, a German research group managed to predict which volunteers would group together simply by comparing their body odor – both through the noses of human subjects and with an electronic nose (a device that looks like an old CB -radio with hose).

Those people who smelled similar were more likely to enjoy talking to each other and also reported that they had instant chemistry. This is consistent with previous research that suggests we unconsciously choose friends with whom we share some genes.

The current emotional state also changes in this way: we can literally smell it when someone is in a good mood. In an experiment in the Netherlands, volunteers wore cotton pads under their armpits while they watched light-hearted videos. When other volunteers later sniffed these pads, their mood improved: their laughing muscles responded.

According to the study, women are particularly sensitive to the smells of anxious men

However, body odor does not only convey good feelings. A 2020 study by Bettina Pause and her colleagues found different brain reactions in women to the sweat of men who had played an aggressive or a peaceful computer game.

It turned out that women were also particularly sensitive to the smells of fearful men: they were more likely to shy away from taking risks in a trust game. “Fear signals: Please, I need help!” says Pause. According to her, this could be why women are more sensitive to the smell of fear – historically, it was women who looked after the young and weak in critical situations.

Such evolutionary connections could also explain why women with a good sense of smell perform better on tests of empathy, as another small study by Düsseldorf psychologists from 2022 showed.

In general, a sensitive nose seems to enrich our social life. Those who were better at distinguishing everyday smells also felt less lonely, according to a US study. Other studies have shown that people with a better sense of smell have a larger social network, more friends and contacts with friends. Imaging studies indicate that the same neural networks are related to the sense of smell and to the size of social networks.

Which substances in body odor exactly influence our relationships? Research is still uncertain

However, exactly how humans perceive and react to body odors remains a major mystery. “It’s a complex problem that we still need to solve,” says Johan Lundström, a neuroscientist at the Karolinska Institute in Sweden.

Researchers are only gradually finding out which chemical substances in body odor influence our relationships. One of these molecules could be hexanal, which gives off the pleasant smell of freshly mown grass and appears to increase confidence in people.

But we don’t yet know whether those who have more hexanal in their body odor are actually perceived as more trustworthy, says Monique Smeets, a social psychologist at Utrecht University in the Netherlands.

Smells are the only information that can be trusted

Further research is likely to follow because, as Agron says: “The pandemic has put the sense of smell in the spotlight.” Omicron appears to harm the nose less than previous Covid variants. But a study from 2023 estimated that almost twelve percent of adults of European descent infected with omicron suffered from smell disorders.

A loss of smell means that those affected have to forego unconscious but potentially important information. Because body odors are “honest” – unlike words or facial expressions, we cannot fake them. “I can laugh even though I’m sad or aggressive. “However, I cannot intentionally change my chemical messages,” says Pause. “Such information is the only one that can be trusted.”