Your sense of smell is swayed by your sense of identity
You might not understand what you find to be stinky as well as you think you do. One might assume that something you find repulsive is a fairly indelible judgement— you think stinky socks smell gross because you find it to they have a gross smell, right? However, your relationship with the source of the sweat, boogers, or whatever may matter as much as the dirt, bacteria, or whatever else. The closer you identify with the source of a stink, the less it bothers you.
Sniffing the same sweat
An experiment at the University of St. Andrews asked students to smell three sweaty shirts, telling them they were studying odorless pheromones. The shirts actually all had sweat from the same person, leaving any perceived differences in their particular odor to the mind of the sniffing volunteer. To measure how unacceptable people found each sweaty shirt, researchers secretly kept track of how long people waited, or rushed, to use some hand washing stations across the room. Presumably, the less you could tolerate a certain shirt, the sooner you’d want to wash its stink off your hands.
The differences people may not have realized they were picking up on was the printing on the shirts, rather than the sweat content. One shirt was blank, one had a logo from St. Andrews and one from the rival school, Dundee University. Students generally were more tolerant of sweat from their own school, with the St. Andrews logo somehow acting as a visual deodorant. The blank shirt was usually rejected quickly, while the Dundee shirt varied depending on prompts from the researchers. If students were asked questions about students in general, both schools’ shirts seemed to be more acceptable than the blank shirt. If students were asked about St. Andrews specifically, they were more likely to reject the smell of the Dundee shirt instead.
The last bit of manipulation is a key demonstration of what was driving participants’ reactions. The more closely people identify with a group, the more acceptable the fallibilities (or sweat) of that group become. So when the group in question was students, the blank shirt became the extra-stinky outsider. When identifying as St. Andrews students, Dundee students were thrown into greater, smellier contrast. This may seem similar to when people find their own farts to be less offensive because of their biological familiarity, but the fact that these shirts’ supposed smells were so interchangeable speaks to a less objective measure than one’s own microbiome. If opinions on something like smells can be reshaped based on a malleable sense of identity, we may be well served to remind ourselves of such biases when forming opinions on more important matters.
Source: How Disgusting Are Other People? by Daniel Yudkin, Scientific American