Valentine’s Day. Love it or hate it, this day marks its presence every year, bringing with it all the trappings of pink, red, heart-shaped eyes, and overpriced chocolates. But beyond these outward expressions of love, however, does there exist an innate force that draws us toward certain people while pushing us away from others?
Photo by Sharon McCutcheon on Unsplash
Wedekind and colleagues (1995) would argue that such “forces” do, in fact, exist. They conducted an experiment in which a group of male college students wore the same shirt to bed for two nights. These shirts, now marked by their odor, were then rated on pleasantness by women who were in the middle of their menstrual cycle (i.e., during which the sense of smell is heightened). The researchers found women preferred the shirts of men whose immune systems were most different from their own, as determined by genes that control immune response known as the histocompatibility complex (MHC). The researchers concluded that this preference stems from the biological desire to have healthy children, which in turn results from parents who have diverging immune systems. More recent studies have also highlighted the importance of MHC. Research da Graça Bicalho (2009) collected genetic information from 90 married couples and compared them to 150 others, and found that couples who were married were much more likely to have MHC and immune system dissimilarities than others.
As these findings suggest, perhaps opposites do – in fact- attract!
– Aditi Iyer