True friends stick with one another despite problems and sweaty shirts, a new study has found. Researchers from Sussex University and St. Andrews University have discovered that people are less disgusted by their peers' odor than those who belong to a different group.

The team put groups of students to the test and measured their disgust over a pile of sweaty shirts. Results show that participants are able to put off the bad smell of the shirts if the owner is identified as a member of the same group they are in. Meanwhile, the subjects showed completely different reactions if they were made to believe that the shirt belongs to another group.

"This difference is explained by the similarity to self of ingroup members," the authors wrote.

The Sweaty Shirt Test

The study consists of two separate experiments.

The first one involved 45 female students from Sussex University who were asked to smell a shirt with a logo of their rival school, Brighton University. The students were then asked to sniff a shirt worn by a research assistant for one whole week. While at it, the students were also asked to consider themselves as an individual, a Sussex student and a plain student.

For the second experiment, 90 male and female St. Andrew University students were asked to sniff three different shirts - one with the logo of their own university, one with the logo of rival Dundee University and one that has no logo at all. Little did they know that the three shirts were worn by only one research assistant during an intense one-hour workout.

The students were also asked to identify themselves as either a plain student or a student of their own school.

The Verdict

For the first study, the students showed less disgust over a shirt, which they believed was worn by a student from the same school. Conversely, the participants were greatly disgusted after smelling the shirt of a person they believed came from the rival university.

"This reduction in the response to core disgust from a stimulant from within a person's own social group is significant because it helps us to understand how group behaviour becomes possible," said study author John Drury. "Essentially, it frees people to cooperate with each other, and to work together effectively."

For the second study, the researchers surveyed the disgust of the participants after smelling the shirts. To do this, they looked into how quickly the students walked to the sink and how much soap they used to wash their hands.

Analysis shows that students walked more rapidly and used more soap after being in contact with a shirt from a rival school than from a fellow student.


The findings have two implications. First, it highlights the importance of social group borders in toning down instinctive distaste. Second, the results show the role of disgust in basic group processes, including the level of cooperation and harmony among members.

The study was published in Proceedings of the National Academy of Sciences on Monday, Feb. 22.

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