A new study from the University of British Columbia in Canada has answered the age-old question, "Why do women sleep in their partners' shirts?" Turns out it may have something to do with alleviating stress.
When my partner is away, I have been known to sneakily pilfer a shirt or two from his closet, to wear around the house or as I do the weekly shopping.
That's more because I miss him than thanks to his sense of style — which might need some adjustments, if you ask my opinion — but new research suggests that there may be a hidden reason behind my compulsion, and it's one that I'm not consciously aware of.
A study by the University of British Columbia in Vancouver, Canada, suggests that a male partner's smell may have soothing effects for women, while the smell of strangers triggers the opposite signal in our brains.
"Many people," explains lead study author Marlise Hofer, of the Department of Psychology, "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."
The researchers' findings were published earlier this week in the Journal of Personality and Social Psychology.
The smell of comfort
Hofer and her team worked with 96 heterosexual couples. The men were required to wear a clean T-shirt for a day and asked not to use any deodorant or other scented cosmetics, smoke, or eat foods that might influence their body odor.
After the 24 hours, the men's T-shirts were frozen to make sure that their scents were kept intact on the clothes.
As part of the experiment, women were later asked to smell, at random, either a shirt that hadn't been previously worn, the shirt that had been worn by their romantic partner, or a shirt that had been worn by a stranger. None of the women knew what shirt they had been assigned to sniff.
To raise the women's stress levels, they were also put through a mock job interview and asked to solve a mathematical problem. To measure their actual stress levels, the female participants were questioned about their perceived stress.
Saliva samples were also collected, in order to measure the concentration of cortisol, which is a hormone released when we're exposed to stress factors.
The women were asked to perform these smell tests rather than their male partners because, as the researchers explain, women have a stronger sense of smell than men. As one study previously covered by Medical News Today shows, women have up to twice as many smell-related neurons in their brains.
Hofer and team found that the women who sniffed the T-shirt worn by their partner exhibited lower levels of perceived stress both before the stress tests (stress anticipation) and in their aftermath (stress recovery).
Moreover, the women who correctly identified the shirt as having been worn by their partner also had lower cortisol levels. This, the scientists explain, may suggest that conscious association of smell with the image of a romantic partner has further soothing effects.
At the same time, the females who had to sniff a stranger's shirt exhibited increased levels of the stress hormone, which led Hofer and team to hypothesize that it may all be down to our in-built mechanism of self-preservation.
"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," says Hofer, adding, "This could happen without us being fully aware of it."
Senior study author Frances Chen suggests that these findings may prove useful for loving couples who have to face the stress of temporary separation due to work trips or other factors outside of their control.
"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," Chen recommends.