Can Sweat from a Happy Mood Change Responses? An Experiment with Added Perfume

Can body odor produced during a happy mood influence another person’s responses? In a 2022 study, women who smelled sweat from men in a positive-mood condition generated more uses for objects, across a wider range of categories, than women who smelled sweat collected during a neutral mood. In a separate physiological assessment, heart rate decreased more, and adding perfume did not clearly change that response.

The study addressed two questions: whether information associated with positive emotion can be conveyed through body odor, and whether adding perfume changes the response.

Collecting sweat during positive and neutral experiences

The sweat donors were 21 men. One day apart, they watched 30-minute videos under a positive-mood induction condition and a neutral condition. The order was randomized, but in the positive condition they watched in groups of three and received gifts beforehand, whereas in the neutral condition they watched alone. Thus, the social setting differed as well as the videos.

Sweat was collected on gauze pads placed under the arms. Samples were selected from eight donors whose self-ratings showed a sufficiently strong response to the mood induction. Samples from four donors were pooled for presentation to receivers. This design did not establish that everyone produces the same “smell of happiness”; it selected donors who showed a clear difference between conditions.

The receivers were 64 women recruited as young, heterosexual, nonsmoking women of European descent who used hormonal contraception. Sixteen completed both physiological measurements and behavioral tasks; 48 completed only the behavioral tasks. Some data were lost because of technical problems.

Heart rate decreased more with sweat from the positive condition

For physiological measurements, sweat from the positive and neutral conditions was each presented with and without perfume, alongside a perfume-only stimulus. The perfume was a diluted fragrance concentrate from a commercial perfume liked in preliminary testing, with two drops added to the sweat samples. This was not a comparison of perfume applied to people’s skin.

The apparatus delivered each stimulus to the nose for five seconds, followed by 60 odorless seconds before the next stimulus, with each stimulus measured three times. Heart rate was compared over 10-second windows before and after presentation. It decreased by approximately 0.96 beats per minute on average with positive-condition sweat and by approximately 0.05 beats per minute with neutral-condition sweat; this difference between conditions was significant.

Adding perfume did not have a clear effect on heart rate, and skin conductance showed no significant changes associated with either sweat condition or perfume. Perfume did, however, increase sniff volume and duration. Bodily responses differed depending on the measure.

Adding perfume made an intensity difference between sweat conditions perceptible

In verbal ratings by these 16 women, adding perfume increased pleasantness, intensity, and familiarity. Ratings of how much the odor elicited happiness or well-being also tended to increase, but the result did not reach significance, with p = 0.062.

When positive- and neutral-condition sweat were compared, the former was rated as more familiar. Intensity also showed an interaction between sweat condition and perfume: positive-condition sweat smelled stronger when perfume was added. Without perfume, that intensity difference was not clear.

The authors interpret this as suggesting that perfume may sometimes make differences in sweat characteristics easier to perceive rather than simply masking them. However, positive-condition sweat itself was not rated as more pleasant or as producing greater happiness. The interpretation that happiness was transmitted rests mainly on indirect physiological and behavioral measures.

More ideas for uses, but no uniform increase in originality

For the behavioral tasks, participants were randomly assigned to positive-condition sweat, neutral-condition sweat, leather odor, or clean air. Stimuli were presented for five seconds every 30 seconds during the tasks. Perfume was not tested in this part of the study.

The central comparison involved 16 women smelling positive-condition sweat and 16 smelling neutral-condition sweat. In a task requiring unusual uses for six objects, including a brick, a pencil, and a shoe, with two minutes per object, the positive-condition group produced more answers across a wider range of categories. There were no clear differences in originality or in how elaborately the answers were described.

The other task was to use a box, drawing pins, a candle, and related materials to attach the candle to a wall without wax dripping onto the table or floor. Seven participants in the positive condition and nine in the neutral condition solved it within the time limit; success rates did not differ significantly. Among only those who solved it, the positive-condition group found the solution faster.

These behavioral comparisons used one-tailed tests in the prespecified direction of better performance in the positive condition. In particular, the solution-time result compares successful participants only, so it does not mean the task became easier for everyone to solve. Ratings such as pleasantness and happiness after the behavioral tasks also did not differ between the two sweat conditions.

How should the interpretation of emotional transmission be understood?

Combining the heart-rate decrease with performance on the idea-generation task, the authors concluded that the results supported the possibility of positive emotion being transmitted to receivers through body odor. They also acknowledged that this evidence was indirect.

The study did not identify emotion-specific compounds, and neither reduced heart rate nor increased idea generation uniquely signifies happiness. Samples came from a small number of selected men, and receivers were also a restricted group of women. Participants were not told which stimulus condition they received, but the study was single-blind.

For perfume, the study examined physiological responses and ratings for only one fragrance under one set of conditions. Whether the creativity-related changes persist when perfume is added, and whether the same effects occur in everyday interactions, remain questions for further testing.

Summary

Compared with sweat from the neutral condition, sweat collected from men during positive-mood induction produced a greater decrease in women’s heart rate and more responses and categories in an object-use task. In contrast, originality, the proportion solving the problem, and self-reported happiness did not clearly increase.

Adding perfume changed pleasantness and sniffing behavior and revealed an intensity difference between sweat conditions, but its additional effect on heart rate was not clear. By examining body odor and perfume together through physiological, verbal, and behavioral measures, the study provided new clues about emotional transmission.

The research was supported by Shiseido and an ANRT doctoral grant, and the paper acknowledges fragrance supplied by Firmenich. Several authors were affiliated with Shiseido at the time. The authors declared no conflicts of interest and stated that authors from the Lyon Neuroscience Research Center led data collection and statistical analysis.

Reference

Ortegón SR, et al. And I’m feeling good: effect of emotional sweat and perfume on others’ physiology, verbal responses, and creativity. Chemical Senses. 2022;47:bjac012. doi:10.1093/chemse/bjac012