HOW DISGUST LEADS TO SILLY DECISIONS

A WEEKLY PICK OF STIMULATING IDEAS AND OPINIONS THAT HAVE APPEARED IN OTHER MEDIA, ONLINE AND OFFLINE

At Times, The Seemingly Gross Things We Reject Aren’t Bad In Themselves But Contaminated By Association With Unpleasant Ideas And Experiences

If you see a packet of potato wafers floating in an open sewer, will you fish it out if it is still tightly puffed with nitrogen? Probably not. But if a packet you have bought slips out of your hand, will you leave it on the shop floor, or pick it up, rip it open and start munching? The shop floor is as dirty as the street outside, and the wafers in both cases are uncontaminated, so why does only one packet seem yucky?

It’s because our perception of things is not based on their objective properties alone. For instance, “people refuse to drink orange juice from unused urine collection bottles, eat soup served in a brand-new bedpan, or touch delicious fudge baked in the shape of dog faeces,” says an article in The British Psychological Society Research Digest.


Our perception of things is often based on their history: “where they have been, what they have touched, and who has touched them — because we subscribe to the notion that objects have an underlying reality, an essence.”

What if you had dropped your sealed packet on the floor of a public toilet freshly mopped with disinfectant? This time again, the association with a repugnant place — a public toilet — might gross you out, never mind the disinfectant.

Experiments by University of Pennsylvania psychology professor Paul Rozin, who specialises in the study of disgust, show how irrational our perception of disgust can be. In one survey, Rozin and his colleagues asked 2,600 Americans if they would like to drink water that had been recycled from sewage. The water met all quality criteria and was perfectly safe to drink.

The group split almost equally between those who were willing to drink the water, and those who absolutely would not or preferred not to drink it. Further questioning showed how irrational the second group’s choice was: “Even though sewage water that is boiled, evaporated, and condensed is purer than tap water, participants overwhelmingly preferred tap water. Furthermore, compared to tap water, participants were more willing to drink bottled water that was filtered from tap water, even though the two are equally pure. It’s like running your clothes through the wash twice.”

Even quirkier was the respondents’ belief that the recycled water would become cleaner if it was left inside a reservoir or aquifer for some time “even though feeding recycled water back into a natural system actually decreases its purity.” Rozin inferred that this was down to the idea of spiritual purification from contact with nature. “Just like we’re more willing to wear Hitler’s sweater if it supposedly came in contact with Mother Teresa.”

Largely, it seems, people consider disgusting things irredeemable. What’s become dirty or contaminated stays that way. When they were asked in another experiment whether they would drink clean water that had touched a “heat sterilised” cockroach, everybody refused. Likewise, people were unwilling to drink out of a sterile glass previously used by a convicted murderer.