New research from the University of British Columbia reveals why it’s a woman’s instinct to wear her boyfriend’s hoodie or snuggle up in his armchair when he’s away: it helps them feel calmer. According to this study “Olfactory cues from romantic partners and strangers influence women’s responses to stress,” the scent of a romantic partner can help lower stress levels, while the scent of a stranger has the very opposite effect and can raise stress levels.

The lead author of the study, Marlise Hofer, a graduate student in the UBC department of psychology, explained her team’s findings: “Many people wear their partner’s shirt or sleep on their partner’s side of the bed when their partner is away, but may not realize why they engage in these behaviors. Our findings suggest that a partner’s scent alone, even without their physical presence, can be a powerful tool to help reduce stress.”

To reach these findings, the researchers studied 96 opposite-sex couples. The men were given a t-shirt to wear for 24 hours, during which they could not apply deodorant (or other scented body products), smoke, or eat smelly foods that might affect their scent. Then, their shirts were frozen to preserve the scents. In the next part of the experiment, the women were randomly assigned to smell an unworn t-shirt, a t-shirt worn by their partner, or a t-shirt worn by a stranger. They were not aware of which they’d been given.

The women then underwent a stress test (which consisted of a mock job interview and a mental math task), answered questions about their stress levels, and provided saliva samples used to measure cortisol levels. After assessing each measurable, the researchers made a few observations: those who smelled their partner’s shirt felt less stressed before and after the stress test; those who correctly identified the t-shirt as their partner’s also had lower levels of cortisol, which suggests that women experience the greatest stress-reducing benefits when they know what they’re smelling; and finally, those who smelled a stranger’s shirt had higher cortisol levels.

While all of the above observations were significant, the researchers found the latter particularly interesting. Why would a stranger’s scent have such a prevalent effect on cortisol levels? They offer an explanation: “From a young age, humans fear strangers, especially strange males, so it is possible that a strange male scent triggers the ‘fight or flight’ response that leads to elevated cortisol. This could happen without us being fully aware of it.”

The study’s senior author Frances Chen, assistant professor in the UBC department of psychology, said the findings may help people cope during times of stress when they’re apart from their loved ones: “With globalization, people are increasingly traveling for work and moving to new cities. Our research suggests that something as simple as taking an article of clothing that was worn by your loved one could help lower stress levels when you’re far from home.”

University of British Columbia (2018, January 4). Stressed Out? Try Sniffing Your Partner’s Shirt. NeuroscienceNews. Retrieved January 4, 2018 from

Hofer, M. K., Collins, H. K., Willans, A. V., & Chen, F. S. (2018, January). Olfactory cues from romantic partners and strangers influence women’s responses to stress. Journal of Personality and Social Psychology. Retrieved on January 5, 2018 from