Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity



Nature 447, 768-771 (14 June 2007)

News Feature

Moral psychology: The depths of disgust

Dan Jones

Dan Jones is a freelance writer in Brighton, UK.

Scholars see disgust as a basic emotion that, like fear, anger, sadness and joy, is found across all cultures. All around the world pus, maggots, rotting food and scavenging animals such as rats produce the distinctive facial expression of disgust: nose wrinkled, mouth agape, lips raised. When severe, the feeling of revulsion can be accompanied by throat clenching, nausea and vomiting. In evolutionary terms, the adaptive value of such reactions seems to be to prevent people from eating contaminated foodstuffs and to get rid of any they have ingested. Disgust is related to bodily purity and integrity, with things that should be on the outside such as faeces kept out, and things that should be on the inside such as blood kept in.


Science 27 February 2009: Vol. 323. no. 5918, pp. 1222 - 1226

In Bad Taste: Evidence for the Oral Origins of Moral Disgust

H. A. Chapman,1 D. A. Kim,1 J. M. Susskind,1 A. K. Anderson1,2

1 Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada.
2 Rotman Research Institute, Baycrest Centre for Geriatric Care, Toronto, Ontario M6A 2E1, Canada.


In common parlance, moral transgressions "leave a bad taste in the mouth." This metaphor implies a link between moral disgust and more primitive forms of disgust related to toxicity and disease, yet convincing evidence for this relationship is still lacking. We tested directly the primitive oral origins of moral disgust by searching for similarity in the facial motor activity evoked by gustatory distaste (elicited by unpleasant tastes), basic disgust (elicited by photographs of contaminants), and moral disgust (elicited by unfair treatment in an economic game). We found that all three states evoked activation of the levator labii muscle region of the face, characteristic of an oralnasal rejection response. These results suggest that immorality elicits the same disgust as disease vectors and bad tastes.


Science 27 February 2009: Vol. 323. no. 5918, pp. 1179 - 1180

From Oral to Moral

Paul Rozin,1 Jonathan Haidt,2 Katrina Fincher1

1Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA.

2Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA.


Is moral disgust an elaboration of a food rejection system?

According to the principle of preadaptation, a system that evolves for one purpose is later used for another purpose. From this viewpoint, disgust originates in the mammalian bitter taste rejection system, which directly activates a disgust output system. This primal route (e.g., bitter and some other tastes) evokes only the output program, without a disgust evaluation phase. During human evolution, the disgust output system was harnessed to a disgust evaluation system that responded not to simple sensory inputs (such as bitter tastes) but to more cognitively elaborated appraisals (e.g., a cockroach). Initially, the evaluation system was a food rejection system that rejected potential foods on the basis of their nature or perceived origin. This was the first "true disgust," because it engaged this evaluation system. Later, through some combination of biological and cultural evolution, the eliciting category was enlarged to include reminders of our animal nature, as well as some people or social groups. This process had adaptive value, because by making things or thoughts disgusting a culture could communicate their negativity and cause withdrawal from them.


Nature 447, 768-771 (14 June 2007)

Reactions to Disgust relate to Political and Ideological views

Dan Jones is a freelance writer in Brighton, UK.


What is the link between visceral or 'core' disgust the feeling you get when you encounter an unflushed toilet and a disgusted reaction to something much more abstract, such as the idea of animal chromosomes in a part-human embryo?

A clue is the language of moral indignation itself. All cultures and languages that we have studied have at least one word that applies both to core disgust (cockroaches and faeces) and also to some kind of social offence, such as sleazy politicians or hypocrites. People labelled as disgusting in this way evoke fears of contamination just as rotting food does.




Return to Emotion

Link to Consciousness Subject Outline

Further discussion Covington Theory of Consciousness