Evidence that people are more put off by bad smells from outsiders has implications for studying social exclusion and discrimination, researchers say

The human capacity for cooperation may rest, in part, on a crucial if unusual knack: our ability to overcome the disgust we feel for others.

With a pile of sweaty T-shirts and a group of student sniffers, researchers showed that people are less put off by bad smells when the offender is identified as a member of their group.



When asked to wash their hands after sniffing a smelly garment, students were slower to reach the sink and used less soap if the T-shirt was made pungent by one of their own.



The findings shed light on a phenomenon known well to new parents, in which the sensory ordeal of changing a baby’s nappy becomes no more challenging than wiping one’s own behind.



But the study highlights how people belong to many groups at once, with each including and excluding different sections of society. The phenomenon is seen in sports fans, where those who define themselves as Arsenal or Tottenham fans, for example, emphasise their membership of the larger group of England fans for international fixtures.



“We are looking at what makes group cohesion possible,” said Stephen Reicher, a social psychologist at St Andrews University. “In many ways, disgust is the social ordering emotion. It’s the emotion that keeps people apart, and if you want people to come together, you have to attenuate disgust.”



The researchers conducted two experiments to investigate. In the first, at Sussex University, students were asked to rate their disgust after sniffing T-shirts that had been worn to the gym and then stored in sealed containers. “They are pretty revolting, I tell you,” said Reicher.



The Sussex volunteers were told that the T-shirts belonged either to students in general, making them garments from members of their own group, or to students from Brighton University, making them items from an outside group. The disgust levels ranked higher when the T-shirts were linked to the outside group.



In the second experiment, at St Andrews University, student volunteers were given a similar task, with the shirts being described as simply student T-shirts, or as garments from students at Dundee University, an outside group down the road. Instead of rating their disgust after smelling the T-shirts, the volunteers were asked to go and wash their hands. They went to the sink faster, and used more soap, if they thought the shirts were from the Dundee outsiders.



“It shows us how important the ways are in which we define group boundaries. It has implications for issues of social exclusion, prejudice and discrimination. It’s about how we define ourselves, who is ‘us’ and who is ‘other’,” said Reicher. Details of the study appear in Proceedings of the National Academy of Sciences.



John Drury, a social psychologist at Sussex University, said: “It helps us to understand how group behaviour becomes possible. Essentially, it frees people to cooperate with each other, and to work together effectively.”

