• Maria Borges

    As we head toward Valentine’s Day, the topic of love seems to be on everyone’s minds. Candy hearts, loads of chocolate, and other romantic gestures are all around us, and love is most certainly in the air. But, have you ever wondered what makes us fall in love with a potential suitor? Is falling in love a conscious decision? Or is it something that happens primarily on a subconscious level? The answer to these questions can be achieved using science. Researchers in the field of evolutionary biology believe that love has strong ties to our evolutionary roots and our noses. According to researchers, humans tend to be attracted to mates based on smell. More specifically, they tend to be more attracted to individuals that have a natural scent that is considered pleasant or sexy.

    The human olfactory system is a powerful system that allows humans to identify smells that could be potentially harmful or advantageous to human survival, so it makes sense that the olfactory system would be closely involved in mate selection. For many years, researchers have studied the importance of smell to various types of animals, but we also know that scent is a powerful force in human lives as well. 

    Smell has been deeply tied to survival of the human race, and the never-ending quest of human species for survival. Studies have shown that newborn babies will scoot themselves closer to the smell of breast milk, and pregnant women develop an enhanced sense of smell that is especially sensitive to toxic or dangerous odors. Adults can easily identify the smell of sweat produced by another human being that has been produced in reaction to anxiety or fear. Perfume companies have been on a tireless quest to recreate pheromone smells that replicate human pheromones, and the quest continues to identify a pheromone that replicated attractiveness. In short, humans are driven by smells. 

    Body odor—a person’s natural scent—has been closely linked to the genes that also encode portions of the human immune system. Specifically, body odor has been linked to the major histocompatibility complex (MHC), which is responsible for determining which potential pathogens are recognized by our immune system. Since the human immune system is responsible for keeping us healthy and keeping infections at bay, it contributes greatly to our overall health and well-being. Across the board, humans tend to be attracted to mates with different MHC make-ups than their own. Hypothetically, a MHC-dissimilar mate could lead to offspring with a stronger immune system, which could prove to be beneficial to the offspring. 

    So, how was this proven by science? Simple! In multiple independent studies, researchers provided new t-shirts to men, and asked them to wear the t-shirts for two days, while avoiding the use of any scented personal care products. At the end of the two-day period, women were given numerous men’s shirts to smell, and the women were asked to rank the smells according to pleasantness and sexiness. The women were all known to be ovulating, because this is when the sense of smell is strongest in females. Blood tests were done to determine the MHC genes for all participants. Overwhelmingly, women preferred the scent of those men that had the greatest differences in MHC genes from their own, meaning that their immune system genes varied the most from the women’s genes. So the next time you are questioning your choice for a love interest, blame your nose.



    Santos, P., Schinemann, J., & Gabardo, J. , Bicalho, MG. (2005, April). New evidence that the MHC influences odor perception in humans: a study with 58 Southern Brazilian students.. Horm Behav., 47(4), 384-8.

    Stephens, K. (2012 March). Odor in Human Mate Choice. Eukaryon, 8 (71-71).

      Back to Articles and Publications

    Request Information

    • (optional)
    • Step 1 of 2


    • Transfer Credit
    • Paying For School
    • Kaplan Commitment