Love can turn our world upside-down, it is often said, with good reason nonetheless. Yet, a recent research shows that it’s not just the “world” in general that love changes, but also something as intimately ours as our sense of smell – women in particular are most affected by it, in that they have problems identifying the smell of their male friends, while they can pick out their lovers’ almost in the blink of an eye.

Johan Lundstrom and Marilyn Jones-Gotman of McGill University in Montreal, Canada, lead researchers of the study, took 20 women with boyfriends, and had them fill out a Passionate Love Scale questionnaire, meant to determine just how in love they were. At the same time, their lovers and some of their male and female friends were asked to sleep in the same room for seven nights in a row, wearing the same T-shirt, with cotton pads sewn into the underarms to soak up the sweat.

Once the week was over, the women, who had been kept apart from their lovers, were asked to pick out the T-shirt of their lover or a friend from three such items, two of which had been worn exclusively by complete strangers. Several such trials showed that, whereas their scores on the questionnaire indicated that women could not tell the difference between a female friend’s tee and that worn by their lovers, in real life, things stand completely differently.

As such, the women included in this research could easily distinguish which was the tee their lover had slept in, but, at the same time, had serious problems identifying a male friend’s. The explanation for this would be, other than the fact that smell and odor play an important part in finding a partner, that the so-called theory of “deflection” still applies. According to it, “being in love with someone entails a reduction in the amount of attention we give to other potential suitors,” as NewScientist explains.