By Nick Grubinger
Dogs and wasps are infamous for their alleged ability to smell fear, but there’s evidence that humans, too, can “smell” emotional information about others. This year, de Groot et al. released a paper outlining a model for assessing the communication of information via body odor. In their research they addressed how someone’s body odor can communicate information regarding a person’s identity, gender, health, and even emotions
The researchers sought to understand the chemical profile of different odors, and how different chemicals can be discriminated from one another. In their model, body odors change from situation to situation, and certain odors consistently appear in the same or similar situations. An association between an odor and the corresponding situation may be tracked, or learned, by other brains. This is where the social component enters, as different individuals may experience the same molecule of odor but interpret it in vastly different ways based on past associative learning. Other brains use learned associations and top-down situational cues to decode new smells.
Now let’s talk emotions. Although there are some challenges in experimenting with smell recognition in humans (i.e. the data may be affected by our difficulty in describing the subtleties of smells), interesting results have been found. Smelling the body odor of fearful individuals receives a fearful facial expression in others, whereas smelling the body odor of happy individuals receives a facial expression of “genuine happiness”.
Anxiety can also be communicated via odor. Women, in particular, respond to the odor of anxious individuals with more emotional involvement than their male counterparts (one study showed that males respond most to the odor of women, regardless of emotion). Individuals who identify as more socially anxious respond more to anxiety-related odors than their non-socially anxious counterparts. This could be due to a number of reasons, but de Groot et al. note that – for those who are anxiously thinking about a situation – it is easier to elicit an association between anxious situations and the smells that accompany them.
It is less clear if humans can successfully distinguish between related emotions, such as fear and disgust, but there is some data that suggests this is possible. With the assessment framework established in this research it becomes more possible to test similar hypotheses.
Smell is perhaps the most overlooked human sense. Human olfaction has a noteworthy power to discriminate between molecules, a remarkable ability to form complex associations, and lies deep in the emotional brain systems. Our sense of smell may be more robust than we give it credit for.
de Groot, J. H., Semin, G. R., & Smeets, M. A. (2017). On the communicative function
of body odors: A theoretical integration and review. Perspectives on Psychological
Science, 12(2), 306-324.