Life in the Fast Lane

Welcome back!

The ewww or disgust factor — a new study explains why we think some things are icky.

Chances are, there’s something that’s guaranteed to turn your stomach. Perhaps it’s the sight and smell of a decomposing pigeon at the side of the road, maggots wriggling from its eye sockets. Or perhaps you squirm whenever you think of your grandmother’s mucky dentures by her bedside. Photo by Temp13rec

Whatever your pet hate, disgust is a basic emotion common to all humans. But for decades, nobody really understood why it existed. Scientists now believe we can find the answer by examining the things that disgust us, reports BBC.

Dr. Valerie Curtis of the London School of Hygiene and Tropical Medicine surveyed people to find out what things they found disgusting. Overall, people reported the same things as revolting wherever they were from. It seems that we are all disgusted by:

Bodily secretions — feces (poo), vomit, sweat, spit, blood, pus, sexual fluids
Body parts — wounds, corpses, toenail clippings
Decaying food — especially rotting meat and fish, rubbish
Certain living creatures — flies, maggots, lice, worms, rats, dogs and cats
People who are ill, contaminated

These universal sources of disgust led Curtis to hypothesize that disgust might be genetic; hard-wired in our brains and imprinted on our biological. But what persistent force in our past drove us to evolve such a powerful emotion?

Things people consistently find disgusting also make us ill. This link convinced Curtis that disgust was a biological mechanism for avoiding infectious disease. Feces, pus and corpses are all sources of dangerous bacteria and viruses; feces alone being the source of more than 20 dangerous bugs. Crucial to this instinctive reaction are visual rules of thumb, which we use to decide what is and isn’t a disease threat.

Visual cues are so powerful, we often squirm at the sight of things we know are harmless, simply because they happen to look like a disease threat.

While many species of worms are harmless — like the earthworm — some have evolved to become human gut parasites. Over the years, we have evolved an instinctive avoidance of gut parasites in animal meat. And this same visual aversion to long, slimy, wriggly animals makes us squirm at the harmless earthworm.

Another vital trigger is our sense of smell. Smell causes such a powerful response in the brain that the US Army has been trying to develop a stink bomb with an odor foul enough to be used for riot-control. The British Police have already expressed an interest in the weapon.

But we can override the disgust response. People find family less disgusting than strangers. And when it comes to sex, we compromise between our instinctive avoidance of disease and our urge to reproduce.

But not everyone believes that we have a genetic, predisposition to be disgusted. Unlike Curtis Paul Rozin of Penn State University thinks that disgust is culturally acquired.

Rozin carried out his own survey on the things people found disgusting and discovered that causes of death rated the highest amongst his North American subjects.

“Anything that reminds us we are animals elicits disgust.” Rozin states. “Disgust functions like a defense mechanism, to keep human animalness out of awareness.

“But few people argue that the way we express our disgust is universal. Humans use a distinctive facial expression to signal disgust.

Professor Paul Ekman of the University of California, San Francisco found that this was identical in different cultures across the globe. We make this expression by screwing up our noses and pulling down the corners of our mouths.

MRI scans also reveal that we use a special part of the brain when we get disgusted — the anterior insular cortex.

Curtis has even claimed that disgust could have been one of the first words uttered by humans. “The word ‘yuck’ is similar in languages all over the world. It seems to be a proto-word.” says Curtis. Photo credits — Sol Dust Love, Fattysammy, Phlewght, Bodnotbod

Paul Rozin took a cockroach that had been sterilized, dipped it into a glass of orange juice, then asked if anyone was willing to take a sip. No volunteers. But I’m sure an involuntary ewww just went through your mind. Rozin specializes in the psychological study of disgust, and he was demonstrating the universal concept of touch transference. Or ‘cooties’. If something repulsive touches something benign, the latter, even if it’s physically unchanged, becomes “infected.” reports TIME.

Fitzsimons and Morales, who teach marketing at Duke and Arizona State University, found not only that some products — trash bags, diapers, kitty litter, tampons — evoke a subconscious feeling of disgust even before they’re used for their ultimate purposes, but they can also transfer their general ickiness to anything they come in contact with. “We were pretty surprised at how strong the effect was.” says Fitzsimons. “This is probably the most robust result in my career.”

The idea that negative qualities can be passed by a touch has become hardwired, says Fitzsimons. (That applies to good qualities too, which is why touching a holy object or person is considered a way of acquiring a little holiness for oneself.) So he and Morales set out to see whether toilet paper and other products could psychologically contaminate food in a shopping basket. They used real shopping baskets, though they did not conduct their tests in a real supermarket, and told subjects that the study had to do only with product preference. Photo by Mr. Truffle

Strong preferences were just what the subjects exhibited. Any food that touched something perceived to be disgusting became immediately less desirable itself, though all of the products were in their original wrapping. The appeal of the food fell even if the two products were merely close together; an inch seemed to be the critical distance.

“It makes no sense if you think about it,” says Fitzsimons. More irrationally still, the subjects were less comfortable with a transparent package than an opaque one, as if it somehow had greater power to leak contamination. Whatever the severity of the taint, the result was predictable.

“We’d take cookies out of the basket and offer them to the subjects,” says Fitzsimons, “and we had some really tempting-looking cookies.” No takers. Moreover, he says, “everything we did suggested that these feelings were below the level of awareness. If we told someone, ‘You didn’t take the cookie because it touched the kitty litter,’ they would say, ‘That’s ridiculous.’”

A product does not stay contaminated forever. The aversion tends to fade after about an hour, though that’s not much use to the grocery store, since shoppers don’t generally return a short while after leaving to reconsider their purchases.

Retailers will be interested to hear about Morales’ next study, on the opposite of the cooties effect. “It turns out that if male customers see an attractive woman touching a garment, like a T shirt, the men are more likely to want it.”

Related stories:
Testicle Eating Festival Galas

Random Posts

• Out of Body Experience – Fact or Sensory Perception
• 35 Ghosts of Nature – Albino Animals of the Wild
• Happy Feet Pair Off – King Penguins Flock to Shore
• Cursed Stolen Pharaonic Carving Returned
• When Pet Owners Go Too Far – Part 3
• Nude Fur Protesters Bleed for Animals
• Year of the Golden Pig – Pig Olympics and Babies
• Otter Love – Otters Holding Hands Video
• Worlds Weirdest and Largest Bikes
• Pre-Teen Bullfighters Latest Craze in Mexico