Why does disgust matter?

Disgust is a powerful emotion that has only recently become the subject of serious study. It plays a role in our everyday avoidances, in our hygiene, in our social relations, in our manners and even in our morality. Since disgust is the first line of defence against infection, it has been a major focus of study for the Hygiene Centre.

Our key contributions and research in this area:

The Parasite Avoidance Theory of Disgust

Val Curtis and Adam Biran first proposed the Parasite Avoidance Theory of Disgust: we suggested that this emotion evolved to help humans (and other animals) respond to and avoid matter that might harbour infectious pathogens and parasites. We then tested this idea in a huge multi-country study hosted by the BBC and showed that images manipulated to suggest an infectious disease threat were consistently found to be more disgusting than those without. We saw that women were more disgust sensitive than men and that disgust sensitivity declined with age.

The London Disgust Scale and the seven types of disgustImages: Michael De Barra

Mícheál de Barra examined the factor structure of disgust for his PhD and found seven different types of disgust:

  • Lesions and body products
  • Sex
  • Poor hygiene
  • Atypical appearance
  • Contamination
  • Some animals, insects and food items
  • Moral infractions

We think that these may correspond to how the brain categorises infectious threats. Mícheál has developed a psychological instrument, called the London Disgust Scale, which we think better measures disgust sensitivity than current tools. We are keen for more work to be done to validate and employ this scale in psychological studies of disgust. The disgust scale can be downloaded for general use here .

Don’t look Don’t touch dont look

Val Curtis recently published a book entitled ‘Don’t Look, Don’t Touch: the Science behind Revulsion’. In this book she sets out a new theory of manners as a set of rules that we learn early on, primarily to avoid disgusting others. Without manners we would fall prey to the infectious diseases carried by others and we wouldn’t be able to reap the huge benefits of being a member of a social species (New Scientist article). Lapses of manners are met with disgust and shunning and occasion feelings of shame in the perpetrator. Similarly, lapses of morality (thieving, hypocrisy, exploitation, rape) are also met with disgust. It seems that manners are the evolutionary precursor to morality, and morality is the big special trick that makes us human: with the ability to cooperate on a massive scale and so transform our planet. Understanding disgust, then, couldn’t be a more urgent or important project.

 Current projects that utilise disgust

Watch the videos blow to see ho we have utilised disgust in some of our recent hand washing campaigns.

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 Full list of publications on disgust

  1. Curtis, Valerie, Míchèal DeBarra and Robert Aunger (2011) ‘Disgust as an adaptive system for disease avoidance behaviour.’ Philosophical Transactions of the Royal Society B: Biological Sciences 366: 389-401.
  2. Curtis, V. (in press). Why disgust matters. Philos Trans R Soc Lond B Biol Sci.
  3. de Barra, Míchèal, Robert Aunger, Diana Fleischman, and Valerie Curtis (submitted) ‘Infection cues and disgust sensitivity’. Journal of Personality and Social Psychology.
  4. Evidence that disgust evolved to protect from risk of disease. CURTIS V, AUNGER R and RABIE T Proceedings of the Royal Society Biology Letters Supplement, 2003, 0144.
  5. Dirt, Disgust, and Disease: Is Hygiene in Our Genes? Curtis, V and Biran, A. Perspectives in Biology and Medicine, 44.1, 2001.
  6. Hygiene: How myths, monsters and mothers-in-law can promote behaviour change. CURTIS V. Journal of Infection 2001: 43: 75 – 79
  7. Dirt and Disgust: a Darwinian perspective on hygiene. Curtis V, Voncken N and Singh S. Medische Antropologie 11 (1) 143-158 1999.

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