We’ve known for decades that animals can sense one another’s fear and alarm from changes in their body odor. According to a Rice University psychologist, the same may be true for humans.

Scientists have long known that mammals, as well as invertebrates and fish can communicate fear through changes in their body odors. Recent studies show that humans may be able to detect happiness or fear in another person based on that individual’s odor.

In a study published in Perceptual and Motor Skills, psychologists Dr. Denise Chen at Rice University and Jeannette Haviland-Jones from Rutgers University confirmed for the first time that natural human body odors do provide information about human emotions that are detectable by other humans.

Focusing on the emotions of fear and happiness, the researchers found that humans can generally distinguish between odors of happy people and those of fearful people, although women appear to have a greater capacity for doing so. Women in their study were able to discriminate between the odors of both happy and fearful men and women. Male subjects, on the other hand, more easily recognized the odor of happy women than that of men and the fearful odor of men compared to that of women.

While women don’t necessarily have a better absolute sense of smell, earlier studies have shown they do exhibit a greater sensitivity to differences in smells than men. "Together with previous research our findings suggest that women may be better able to perceive differences associated with emotionally and sociobiologically significant signals," Chen explains.

The study’s findings also are consistent with prior findings that indicate women are better than men at making fine distinctions between the hand odors of two individuals of the same sex, and they’re better able to identify the sex of individuals based on differences in intensity of breath odors. Women also have been found to better recognize and identify synthetic commercial odors.

Chen and her colleague gathered data from university student and staff volunteers, 40 of whom were women and 37, men. The subjects were asked to view excerpts from a comedy and from a film of snakes, bugs and crocodiles menacing people. Afterwards, they were rated on how happy or afraid they felt during the movies.

They were instructed to shower the night before the session, but to refrain from bathing or using deodorant or fragrance on the day of the session. The subjects wore gauze pads in each armpit while viewing the films. The subjects’ cotton pads were later grouped by movie and sex. One week later in a three- and six-choice task, the same subjects were asked twice to identify each of type of odor within six bottles, two of which contained unused cotton pads.

Currently Chen is conducting studies of other kinds of emotions and their accompanying odors, as well as what may be contributing to individual differences in sensitivity to smell between men and women.

A member of Rice’s psychology department since 2002, Chen earned her undergraduate and master’s degrees from the University of Chicago and her Ph.D. in social and developmental psychology from Rutgers University.

Contact Chen at [email protected]