Celebrated eighteenth-century man of letters Samuel Johnson was well known for his eccentric behavior and disheveled appearance. In an incident that is more likely legend than historical fact, a young woman once challenged him about his lack of hygiene.
“Dr. Johnson,” she said. “You smell.”
“No, madam,” the good doctor replied. “You smell. I stink.”
American culture has long been obsessed with body odor—and removing any trace of it. During World War II, it is said, the Russians knew the Yanks were coming because they could smell the soap. We don’t just wash ourselves; we sanitize and deodorize, almost to an obsessive-compulsive degree. And then we laden our bodies with scents of citrus, spices, and musk.
However, Italian psychologist Mariella Pazzaglia believes body odors have gotten a bad rap, both in our attitudes towards personal hygiene and in the lack of interest shown by other psychologists. In the most recent issue of Current Directions in Psychological Science, Pazzaglia argues that our sense of smell, as used to detect body odors, is an important component of our social interactions and can even trump the information received from vision or hearing.
Smell is one of our three telereceptive senses—that is, senses that provide information about objects at a distance. Touch and taste require bodily contact with the detected object, but not so with vision and hearing, which give us information about the environment extending beyond our bodies. Likewise with smell.
Often we smell other people before we even see or hear them. This is because vision and hearing require focused attention, and we miss things in plain sight when we’re not paying attention. But odor detection works continuously and outside of our conscious awareness. In fact, it’s often the unconscious sensing of a body odor that alerts us to the presence of another person, drawing our visual and auditory attention toward them.
Each of us has a unique body odor, and this allows us to recognize kin, who have a similar smell. Newborn babies recognize their mothers by smell, so experience sniffing family members isn’t necessary. People with body odors distinctly different from our own are rapidly and unconsciously identified as strangers—and possibly enemies—thus triggering an automatic state of arousal.
Body odor thus provides us with information about another person’s genetic makeup. If they smell like us, they’re probably family and will provide us with social support. And if they smell different, they probably don’t have our best interests in mind.
Of course, the evolutionary logic is reversed when it comes to mating. The whole idea of sexual reproduction is to get fresh genes into the next generation. We want to avoid inbreeding, so someone who smells like us won’t do. Perhaps body odor is even what drives incest avoidance in both humans and other animals.
Thus, unfamiliar body odors can be attractive in the sexual arena. In a series of experiments, young adult males wore medical face masks as they viewed photos of female models. When the masks were laced with a faint scent of citrusy grapefruit, the men rated the women as five years younger on average than their real age. Another group smelling a fragrance of floral and spice notes estimated the women as weighing four pounds less on average than their actual weight. In other words, our sense of smell can actually influence our visual perception.
Someone who doesn’t smell like us must have a different mix of genes, and so they might be good mating material. However, body odors also signal gender, age, health, fertility, and perhaps even emotional stability—all factors that are important in the mating game as well. For example, men rate photos of women as significantly less attractive when they’re exposed to the smell of a woman’s tears.
More generally, we use body odors to assess the emotional states of others. When we’re anxious, we give off particular odors that others can smell and react to. Body odor appears to plays a role in emotional contagion, in which one person’s heightened state of arousal spreads to others in the group. Apparently, we really can smell fear in other people.
In the end, it’s important to keep in mind that our senses don’t work in isolation. Rather, our brain integrates information from each sense to build our conscious experience of the world. Because smells are processed rapidly, they can influence the way that information coming from the eyes and ears is interpreted. And because most smells are processed at an unconscious level, we’re generally unaware of important ways our body odors impact our social lives.
Pazzaglia, M. (2015). Body and odors: not just molecules, after all. Current Directions in Psychological Science, 24, 329-333.
David Ludden is the author of The Psychology of Language: An Integrated Approach (SAGE Publications).