Disgust discussed: The psychology of revulsion

I have to be honest and say that today’s blog on the psychology of revulsion was inspired by reading another blog (on the same topic) – Inside the human revulsion (disgust) reflex” written by Don Burleson. The reason I am so personally interested is that get periodic emails from readers of my blog saying that what I have written is “gross”. “revolting” and/or “disgusting” (my blogs on necrophilia, zoophilia, vorarephilia, menophilia, apotemnophilia, coprophilia, eproctophilia, emetophilia and formiciphilia being the guilty parties). My interest is in the question of what makes these behaviours so revulsive (i.e., a sudden strong change or reaction in feeling, especially a feeling of violent disgust or loathing) and repulsive (i.e., causing repugnance or aversion; disgusting)? As Burleson’s blog notes:

“Behaviors that are uniform across the world can be teased-out to reveal the truly universal human behaviors, manifestations of our basest raw instinct, instinctive reactions without any cultural or social bias. One such universal behavior is revulsion, the natural squeamish behavior that once served to protect our bodies from carrion and now has become a major entertainment phenomenon”.

Burleson also claims that we as humans love to become disgusted. So what evidence is there (besides our seemingly insatiable appetite for reality television shows)? Dr Valerie Curtis (London School of Hygiene and Tropical Medicine, UK) has been carrying out research in different countries to see which things and activities are perceived as disgusting. Some things are very cultural (e.g., in India, meals cooked by menstruating women are viewed as disgusting). However, there were many things perceived as disgusting and revolting irrespective of where people lived. This included:

But overall, people kept reporting the same things as revolting

  • Bodily secretions (faeces, vomit, sweat, spit, blood, pus, sexual fluids)
  • Body parts (wounds, corpses, toenail clippings)
  • Decaying food (e.g., rotting meat and fish, rubbish)
  • Certain living creatures (e.g., flies, maggots, lice, worms, rats)
  • People who are ill and/or contaminated

Given the widespread cultural similarities, Curtis speculates that disgust might therefore be genetic (i.e., “hard-wired in our brains and imprinted on our biological code by millions of years of natural selection”). The similarity between most of these things is that they are things that have a high association with illness across all cultures. In short, Curtis believes that disgust is (or was) an evolutionary biological mechanism that helped us avoid infectious disease. The latest 2011 paper by Curtis and her colleagues was unequivocal:

“Disgust is a fundamental part of human nature. Darwin was the first to propose that disgust is expressed universally  and many studies since then have supported this proposal. Though there has been no systematic cross-cultural survey of the objects and events that elicit disgust in humans, the available data suggest that there is a universal set of disgust cues. These include bodily wastes, body contents, sick, deformed, dead or unhygienic people, some sexual behaviour, dirty environments, certain foods – especially if spoiled or unfamiliar – and certain animals”.

However, Professor Paul Rozin (Penn State University, US) argues that disgust is culturally acquired because his studies have shown that among North American participants, it was ‘death’ that was rated as the most disgusting thing. He argues that: “Anything that reminds us we are animals elicits disgust. [It] functions like a defence mechanism, to keep human animalness out of awareness.” An article written by Erik D’Amato on disgust in Psychology Today argued that disgust is both instinctual and learned:

“We are socialized by our disgust and, in turn, use it to socialize others; what better way is there to stop people from doing something socially undesirable than to “make” that something–whether eating rancid meat or, in India, defying the caste system, disgusting.”

One of my favourite papers in the area of psychological disgust was by Professor Andrea Morales and Professor Gavan Fitzsimons who published a paper in Journal of Marketing Research on “product contagion”. Their research showed how consumer evaluations can change in response to physical contact with products that elicit only moderate levels of disgust. Using evidence from six studies, Morales and Fitzsimons developed a theory of product contagion, in which disgusting products are believed to transfer offensive properties through physical contact to other products they touch.

The law of contagion argues that objects or people can affect each other merely by touching. Although it is clear that contagion beliefs influence behaviour in both primitive and advanced societies, Morales and Fitzsimons say it is still unclear how they became so prevalent. In a series of studies, Morales and Fitzsimons found that some products (e.g., rubbish bags, nappies, cat litter, tampons) evoke a subconscious feeling of disgust even before they’re used for their ultimate messy purposes. However, they also found that touching these products can also transfer their disgust to anything they come in contact with. In an interview with Time magazine, Professor Fitzsimons said: “We were pretty surprised at how strong the effect was. This is probably the most robust result in my career”.

The study suggests an evolutionary basis for shopping preference and the researchers agree with Curtis that disgust is hard-wired (i.e., low-threshold revulsion protected our ancestors from eating rotten or poisonous food or touching animals that had died of infectious disease). Morales and Fitzsimons wanted to examine whether products like toilet paper psychologically contaminated food in a shopping basket.

They found that any food that touched something perceived to be disgusting became immediately less desirable (even though all of the products were in their original wrapping). Food appeal fell even if the two products were close together but didn’t touch. Everything the researchers did suggested the feelings of disgust were below the level of awareness. They also found that the product didn’t stay “contaminated” as the effect faded after about an hour. The aversion tends to fade after about an hour.

One area where there is no debate is the way in which we as a human race express our disgust facially. Research by Professor Paul Ekman (University of Califiornia, US) has consistently shown that humans across different cultures use a distinctive facial expression to signal disgust and appears to be universal (i.e., screwing up our noses and pulling down the corners of our mouths). Biological research using magnetic resonance imaging scans also show that one particular part of the brain (i.e., the anterior insular cortex) is activated when we are disgusted.

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Burleson, D. (Undated). Inside the human revulsion (disgust) reflex. Burleson Consulting. Located at: http://www.dba-oracle.com/p_human_revulsion_instinct_behavior.htm

Curtis, V., de Barra, M. & Aunger, R. (2011). Disgust as an adaptive system for disease avoidance behaviour. Philosophical Transactions of the Royal Society B, 366, 389-401.

D’Amato, E. (1998). The mystery of disgust. Psychology Today, January 1. Located at: http://www.psychologytoday.com/articles/200909/mystery-disgust

Lemonick, M. (2009). Why We Get Disgusted. Time, May 24. Located at: http://www.time.com/time/magazine/article/0,9171,1625167,00.html

Morales, A.C. & Fitzsimons, G.J. (2009). Product contagion: Changing consumer evaluations Through Physical Contact with “Disgusting” Products. Journal of Marketing Research, XLIV, 272–283

About drmarkgriffiths

Professor MARK GRIFFITHS, BSc, PhD, CPsychol, PGDipHE, FBPsS, FRSA, AcSS. Dr. Mark Griffiths is a Chartered Psychologist and Distinguished Professor of Behavioural Addiction at the Nottingham Trent University, and Director of the International Gaming Research Unit. He is internationally known for his work into gambling and gaming addictions and has won many awards including the American 1994 John Rosecrance Research Prize for “outstanding scholarly contributions to the field of gambling research”, the 1998 European CELEJ Prize for best paper on gambling, the 2003 Canadian International Excellence Award for “outstanding contributions to the prevention of problem gambling and the practice of responsible gambling” and a North American 2006 Lifetime Achievement Award For Contributions To The Field Of Youth Gambling “in recognition of his dedication, leadership, and pioneering contributions to the field of youth gambling”. In 2013, he was given the Lifetime Research Award from the US National Council on Problem Gambling. He has published over 760 research papers, five books, over 150 book chapters, and over 1500 other articles. He has served on numerous national and international committees (e.g. BPS Council, BPS Social Psychology Section, Society for the Study of Gambling, Gamblers Anonymous General Services Board, National Council on Gambling etc.) and is a former National Chair of Gamcare. He also does a lot of freelance journalism and has appeared on over 3500 radio and television programmes since 1988. In 2004 he was awarded the Joseph Lister Prize for Social Sciences by the British Association for the Advancement of Science for being one of the UK’s “outstanding scientific communicators”. His awards also include the 2006 Excellence in the Teaching of Psychology Award by the British Psychological Society and the British Psychological Society Fellowship Award for “exceptional contributions to psychology”.

Posted on July 5, 2012, in Case Studies, Fame, Mania, Obsession, Paraphilia, Popular Culture, Psychology, Sex and tagged , , , , , , , . Bookmark the permalink. Leave a comment.

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