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Keep calm! A study of dental students suggests that dentists can smell when a patient is anxious, and it makes them more likely to make mistakes and perform badly.

The finding is the first real-world evidence that chemical signals hidden in our body odour can betray our emotions and influence the behaviours of those around us, says Valentina Parma at the International School for Advanced Studies in Trieste, Italy.

Plenty of lab-based experiments have found that body odours of people experiencing emotions – particularly negative ones like disgust, fear and anxiety – can influence our perception of other people, even though we are rarely able to put a finger on why, or even describe the smell at all.


To investigate whether body odour can signal someone’s anxiety in a more realistic setting, Parma’s team turned to dental students, as dentists meet many anxious people as part of their daily work. They asked 24 student volunteers to each donate two T-shirts – one of which was worn during a stressful exam, the other during a calm lecture.

More mistakes

The team then doused the T-shirts with a chemical that masks body odour, so that it wasn’t possible to consciously smell any body odour on them. When the T-shirts were presented to a different group of 24 dental students, they said they couldn’t detect any difference between those taken from the stressful or the relaxed situations.

Next, mannequins were dressed in the donated T-shirts, and the second group of students had to perform dental treatments on them. Each student was graded on their performance by examiners – and they performed significantly worse when treating mannequins wearing T-shirts from people who’d been stressed. Mistakes included being more likely to damage neighbouring teeth, for example.

Parma thinks the scent of anxiety could be triggering the same emotions in those who subconsciously smell it. “It’s quite fascinating,” says Pamela Dalton at Monell Chemical Senses Center in Philadelphia. “It helps us understand how we can communicate without language.”

Managing anxiety

The same phenomenon is likely to occur in other settings, too. Doctors might also be able to smell their patients’ fear, for instance, and sitting close to an especially nervous person during an exam might impact your own grades, says Parma. Body odours may influence work performance, too, if you’re within sniffing distance of your boss or colleagues.

Parma doesn’t yet know if fully-trained dentists are as vulnerable to body odours as dental students, and plans to investigate this in future research. If this is the case, she hopes that training dentists and medical professionals to be aware of potential biases might improve patient care.

As for the patients, there’s likely little we can do to mask our body’s chemical signals, says Parma. “I don’t think we’ll be able to develop an anti-anxiety deodorant, unless we find the molecule responsible,” she says. A better approach is to make dentists aware of the effect, and help manage their anxiety, she says.

Journal reference: Chemical Senses, DOI: 10.1093/chemse/bjy028

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