Disgust, Racism and the Moral-Conventional Distinction


DanMaroonLakeDaniel Kelly, Department of Philosophy, Purdue University

Introducing Empirically Informed Philosophy of Mind

March 2015 – The bulk of my work on emotion thus far has focused specifically on disgust, but my interests and approach are more eclectic. I am a philosopher of mind and moral psychology with a decidedly empirical orientation, and am interested in understanding distinctively human minds, emotions, and activities from a broadly naturalistic point of view, and then thinking through the philosophical and ethical ramifications of that understanding. I’m also particularly attracted to the perspective provided by evolutionary theory, and the light it sheds on the ways humans are continuous with other animals, as well has how we and our minds are unique.

The discipline-spanning character of evolutionary theory also fits well with my impulse to integrate. I often find myself searching for points of contact and common ground between different insights and theoretical approaches found in philosophy, psychology, anthropology and other areas of research, and looking for ways in which they can be synthesized to paint a more complete picture of the Who We Are and How We Got Here and to formulate and address pressing questions about What It All Means.

disgust 2Obviously this all covers a lot of ground, and in practice taking this interdisciplinary angle can be demanding. For instance, doing it right requires that one be conversant in each of the different disciplines on which one is drawing, and able to competently navigate their proprietary concerns, methods, and dialects. It also means taking on the typical dangers associated with pursuing breadth rather than aiming primarily for a narrower depth. But I believe that this kind of integrative and interdisciplinary research is crucial, and so worth the effort and risk.

I also believe that philosophers, with their distinctive training on theoretical foundations, conceptual precision, and argumentative clarity, are particularly well equipped to make exactly these kinds of contributions. Indeed, many of my early influences were exemplary practitioners of exactly this style of research (especially Dennett 1995, Simon 1996, Griffiths 1997, Mallon and Stich 2000) and I have tried to follow their example in my own work on social norms, disgust, and implicit bias.

Norms and Emotions: Questioning the Moral/Conventional Distinction

As a graduate student I was lucky enough to become a founding member of the Moral Psychology Research Group, and thus had the opportunity to think about and participate in some of the most exciting and important work in that thoroughly interdisciplinary field as it began to take off – and emotions were center stage (see Doris et al 2010). Of particular note was a tradition of experimental work initiated by developmental psychologists suggesting that there exists a crisp, stable, psychologically important and culturally universal distinction between moral and merely conventional norms (Turiel 1983, Nucci 2001).

In this literature, examples of prototypical moral norms included injunctions against pulling someone else’s hair or stealing someone’s scissors, while examples of prototypical conventional norms included rules specifying where to sit during class, or whether it is okay to wear pajamas to school. The research suggested that experimental participants at least tacitly draw a moral/conventional distinction. Violations of moral norms are typically judged to be authority independent, applying generally and to everyone, comparatively serious, and justified by appeal to harm, justice or rights.

Violations of conventional norms, on the other hand, are typically judged to be authority dependent, applying only in certain situations or to certain groups of people, comparatively less serious, and justified by appeal to factors other than harm, justice or rights (such as, for instance, the need for organization and coordination, the smooth running of the classroom). In addition, empirical research also suggested what kinds of violations tend to elicit the two kinds of responses: norms whose violations result in harm, unfairness or the infringement of someone’s rights elicit the moral response, while norms whose violations did not result in harm, an unfair outcome, or the infringement of anyone’s rights elicit the conventional response. Finally, initial cross-cultural research suggested that these generalizations about moral cognition emerge relatively early in development, and hold universally rather than being parochial to a certain age, group, religion, or culture.

This work was grabbing the interest of many philosophers, perhaps most notably Shaun Nichols, whose Sentimental Rules view (2004) posits a psychological explanation of the results of experiments on the moral/conventional distinction. Nichols holds (very roughly) that the moral response is the result of the perceived transgression of a social norm together with an emotional response to that violation, while the conventional response is the result merely of the perceived transgression of a social norm, without any accompanying emotional response.

However, in a series of papers, my co-authors and I argue that the picture painted by the experiments on the moral/conventional distinction is misleading, and that the generalizations drawn from these experiments are in fact false, and so Nichols’ emotion-based explanation of those generalizations may be on the wrong track as well (Kelly et al. 2007Kelly and Stich 2007, Stich et al 2009). Indeed, my own skepticism was hatched when I noticed that many counterexamples to and complications for theorizing about the putative moral/conventional distinction arose from cases that elicited disgust. For instance, work by Jon Haidt and colleagues (1993, 2006) shows that many people give the moral response to norms whose violation elicits disgust, even though no one is harmed, no injustice is committed, and no rights have been violated; examples include masturbating with a dead chicken, eating the family dog, cleaning the toilet with the national flag, and consensual sibling incest.

Angela Jolie kisses her brother at the Oscar's red carpet in 2001

Angela Jolie kisses her brother at the Oscar’s red carpet in 2001

Even some of Nichols own experimental work indicated variation in how different subjects responded to the same disgusting violation of an etiquette norm (spitting in one’s drink before taking a sip out of it at the dinner table). Additionally, closer examination of the available data suggested that the so-called moral and conventional responses themselves are not as disjoint as had been supposed, and the elements that make up each putative response do not cluster together as often as was initially thought. My co-authors and I pressed this skeptical line of argument, gathering data suggesting that, again contrary to the predictions of the received view, some people hold that in some scenarios it would be okay to use extreme training techniques on military trainees or to punish derelict sailors who were found drunk on duty by whipping them, while in some scenarios causing harm in these ways would not be okay (Kelly et al 2007). While we did not offer our own positive hypothesis about the relationships between emotions, social norms, and moral judgment, our aim was to show that one prominent view about those relationships was untenable, and thus clear the way for new research approaches to the topic.

Understanding Disgust 

As mentioned earlier, I initially became interested in disgust by considering the different ways in which it had been found to influence moral judgments and social norms. As I looked further into the matter, it seemed to me that disgust had many other intriguing features, and that it was an emotion whose time had finally come – after years of waiting in the wings it was finally attracting the attention of scores of researchers. Disgust also presented exactly the kind of topic I was looking for, one whose many facets required a thoroughly interdisciplinary perspective to fully explain.

yuck 2Part of what made disgust intriguing was that experimental data seemed to be coming in faster than theory was being developed to account for it. There were a number of competing theoretical proposals in the air, and it wasn’t clear which was correct or whether any were compatible with each other. To the extent that there was a received view, it was probably Paul Rozin’s. Rozin holds that although disgust is different from, and more conceptually sophisticated than, mere distaste – one can be disgusted by things that one had never tasted, or has no intention of ever putting in one’s mouth – disgust is primarily an orally based emotion. He also holds that cultural evolution broadened the scope of the emotion until it also came to function in a number of other domains. For instance, he showed that it can be triggered by reminders of our animal nature like corpses and blood (Rozin et al. 2000).

Alternatively, another rising school of thought saw disgust simply as the human version of the kind of behavioral immune system found in a number of other animals, helping to prevent infection from contagious pathogens by monitoring for, and producing aversion towards, likely sources of disease (see Curtis et al. 2001 and 2004 for arguments and data supporting this view). Together with the research connecting disgust to social interaction and moral judgment discussed above, a more complete view of a surprisingly complex emotion was emerging.

In my work, I attempt to articulate a broader theory that can capture the evidence and insights supporting such views and to show how the different approaches each have an important piece of a complicated puzzle. At the heart of my theory is a dual origins account of the evolutionary history of disgust that I call the entanglement thesis (see Kelly 2011 chapter 2). I draw on a wide range of evidence ranging from anthropology, through developmental, evolutionary, and comparative psychology to support the claim that the emotion was initially formed in our phylogenetic past when two initially distinct cognitive mechanisms – one dedicated to monitoring food intake, the other to protecting against infectious diseases – became functionally entangled to form the single emotion we now call disgust.

I argue that mechanisms performing functions similar to each of these can be found in a wide range of other animals, but that in those other animals they are not merged in the way they are in human beings; thus, there is indeed a sense in which disgust is a uniquely human emotion (as other theorists have previously claimed (Miller 1997, also see Rozin et al. 2000)).

Another intriguing aspect of disgust is that it appears to include features that are universal and largely innate, on the one hand, while other aspects of the emotion appear to be sensitive to social influence and exhibit significant cultural variation, on the other. A central example of a universal feature is contamination sensitivity: when we are disgusted by something , we also tend to become disgusted by whatever else that thing comes into contact with.face

Other examples of universal aspects include the capacity to naturally recognize the disgust response in others, particularly the associated facial expressiVegon often called the gape, and the tendency to become disgusted by a core set of innate disgust elicitors, typically cues that are highly correlated with the increased risk of infection (coughing, open sores, blood and other bodily fluids, decomposing organic material) or the likelihood of causing gastrointestinal distress if consumed (spoiled milk, rotting meat, moldy fruit). However, beyond that core set of innate elicitors, individuals can learn to be disgusted by additional things as well, and individuals raised in different cultures typically learn to be disgusted by different things. Even in the case of food, what is considered a delicacy in one culture is often considered revolting by members of other cultures (even if they haven’t tasted it!): prominent examples include Australia’s vegemite (a spreadable paste made from vegetable and spice additives), France’s escargot, Japan’s sushi, America’s deep fried baconnaise.

Many cultures find forms of “deviant” sexual behavior both disgusting and wrong, but what falls within the range of “deviant” behavior exhibits considerable variation from one culture to the next. More generally, different cultures have their own norms regulating rites of passage, proper behavior in ritual settings, acceptable ways of interacting with members of different classes, castes, or cultures, and many other social and moral issues. Purity norms like these delineate the culture’s “way of life”, and violations of them are considered not just wrong but also often disgusting – morally contaminating and spiritually polluting (Rozin et al 1999). Here again we see significant variation in what elicits disgust, this time in the social and moral domain.

Another aim of my book is to explain this type of variation, and sketch the psychological mechanisms responsible for producing it. Here I first turn to recent work on research on facial expressions. In short, I canvass recent evidence that disgust recognition is esempathic: we easily “catch” the emotions expressed by those around us, and in recognizing that someone nearby is disgusted by something, we ourselves are primed to be disgusted, sometimes actually coming to be disgusted ourselves.

Placing these insights within the context of recent work on cultural evolution, I argue that they reveal an instinctive, non-verbal signaling system that gives disgust an important kind of flexibility, showing how the emotion can admit of the sorts of cultural variation described above. The signaling system allows us to socially transmit information to one another about what is disgusting and important to avoid in local environments, so an individual can easily learn what it is appropriate to be disgusted by in whatever culture they are raised. Thus, differences between cultures about what is considered disgusting can accumulate over time as they are socially transmitted from one generation to the next (see Kelly 2011 chapter 3,).

baconnaiseWhile disgust originates in and remains closely attuned to the concrete realities associated with poisons and parasites, much of the experimental work cited earlier suggests that it is able to exert influence, sometimes covertly, other times more openly, over certain aspects of social and moral cognition. Though many details remain to be learned in this area, I offer a broad theoretical framework through which such findings might be interpreted. I first develop the gene cultural coevolutionary account of uniquely human tribal social instincts, with special attention to the central role it gives to our capacities to socially learn and comply with the social norms of our group, and the corresponding importance we assign to signaling group membership and monitoring others’ behavior for commitment to the group and compliance with its norms (Richerson and Boyd 2001, Boyd and Richerson 2005).

I then argue for what I call the co-opt thesis: as human social life became more complicated, disgust was recruited to provide the motivational component associated with certain tribal social instincts (see Kelly 2011, chapter 4 and Kelly 2013). I point out that its signaling system and susceptibility to social influence made it easily exploitable for these new purposes, and thus disgust acquired auxiliary functions related to certain types of social norms, the construction of social identities, and the monitoring of group membership and tribal boundaries. Moreover, in those cases where disgust is the emotion recruited to provide motivation, activities forbidden by the social norm will be avoided because they will be considered not just wrong but also disgusting, and violators of the social norm can become objects of disgust themselves, morally contaminated by their actions. Likewise, motivation to avoid interactions with members of certain outgroups can come to be infused with disgust, and as a result those individuals and the very symbols of their group can come to considered tainted and polluting.

Finally, I have used this empirically and evolutionarily informed account to provide new theoretical foundations for conclusions about the value of disgust in moral deliberation and justification. More specifically, I have argued that as vivid and aversive as feelings of disgust can be while one is in their grip, there is no reason to think that the emotion is morally “wise” or that it is an intrinsically reliable guide to the moral status of the practices and actions that might elicit it. In other words, merely finding some behavior disgusting is itself never a good reason to think that behavior is morally wrong. Rather, given what we now know about its evolutionary history, psychological functioning, and capacity for variation, we should be skeptical about the idea that the emotion is uniquely sensitive to genuine ethical boundaries, and should do what we can to minimize its role in our social and legal institutions. (Kelly 2011 chapter 5, Kelly and Morar 2014).

Racial Cognition and Implicit Bias

A final strand of my research centers on issues of race and racism where they intersect with psychological work on racial cognition and implicit bias (see http://biasproject.org for further information). The strategy my co-authors and I pursue begins by considering recent empirical research about racial cognition having to do with, for instance, how humans learn racial categories, how we intuitively assign racial membership, and how racial biases can take both explicit and implicit form.

We explore the ways in which such findings interact with issues discussed in the philosophical literature on race. These include issues concerning whether or not racial categories should be eliminated or preserved in an ideal society (short answer: it depends, Kelly et al 2010a) and whether or not psychological explanations depict racism as inevitable (short answer: no, Machery et al. 2010, Kelly et al. 2010b). We also show how social constructivist accounts of race and institutional accounts of racism can be strengthened by incorporating insights from empirical psychology (Mallon and Kelly 2012). Finally, my most recent work in this vein has considered the putative problems implicit biases raise for moral responsibility, especially the fact that those biases can operate automatically and outside the awareness of people who harbor them, and can be diametrically opposed to their considered values.

In response to these problems, my coauthors and I argue that since implicit biases are still knowable and controllable, albeit in non-traditional ways, behaviors driven by them still fall squarely within the realm of moral assessment. We elaborate upon and defend this idea by showing how common norms governing praise and blame can be reasonably extended to apply to such behaviors, and argue that we can and should take responsibility for the effects of implicit biases (Holroyd and Kelly, forthcoming, Washington and Kelly, forthcoming).


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Curtis, V., Aunger, R. & Rabie T. (2004). Evidence that disgust evolved to protect from risk of disease. Proceedings of the Royal Society: Biological Science Series B, 271(4), S131-S133.

Curtis, V & Biran, A. (2001). Dirt, disgust, and disease: Is hygiene in our genes? Perspectives in Biology and Medicine, 44(1), 17-31.

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Doris, J and the Moral Psychology Research Group. (2010). The Moral Psychology Handbook. Oxford: Oxford University Press.

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Haidt, J. (2006). The happiness hypothesis: Finding modern truth in ancient wisdom. New York: Basic Books.

Holroyd, J. and D. Kelly, forthcoming, “Implicit Bias, Character, and Control”. in J. Webber and A. Masala (eds.) From Personality to Virtue, Oxford: Oxford University Press.

Kelly, D., L. Faucher, & E. Machery, 2010a, “Getting Rid of Racism: Assessing Three Proposals in Light of Psychological Evidence”, Journal of Social Philosophy, 41(3): 293–322.

Kelly, D., E. Machery, & R. Mallon, 2010b, “Race and Racial Cognition”, in The Moral Psychology Handbook, J. Doris & the Moral Psychology Reading Group (eds.), Oxford: Oxford University Press, pp. 433–472.

Kelly, D., and Morar, N. (2014). ‘Against the Yuck Factor: On the Ideal Role of Disgust in Society’, Utilitas, 26(2): 153-177. doi: 10.1017/S0953820813000290.

Kelly, D., Stich, S., Haley, K., Eng, S. & Fessler, D. (2007). Harm, affect and the moral / conventional distinction. Mind and Language, 22(2), 117-131.

Kelly, D. and Stich, S. (2007). ‘Two Theories of the Cognitive Architecture Underlying Morality,’ The Innate Mind Vol 3.: Foundations and Future Horizons, Eds. Peter Carruthers, Stephen Laurence and Stephen Stich. New York: Oxford University Press. Pages 348-366.

Kelly, D. (2013). ‘Moral Disgust and The Tribal Instincts Hypothesis,’ Cooperation and Its Evolution, Eds. K. Sterelny, R. Joyce, Calcott, B, & B. Fraser. Cambridge, MA: The MIT Press, pages 503-524.

Kelly, D. (2011). Yuck! The Nature and Moral Significance of Disgust. Cambridge, MA: The MIT Press.

Machery, E., Faucher, L. & D. Kelly, 2010, “On the alleged inadequacy of psychological explanations of racism”, The Monist, 93(2): 228–255.

Mallon, R., and S. Stich. 2000. The odd couple: The compatibility of social construction and evolutionary psychology. Philosophy of Science 67: 133–154.

Miller, W. (1997). The anatomy of disgust. Harvard University Press: Cambridge, MA.

Nichols, S. (2004).  Sentimental rules: On the natural foundations of moral judgment.  New York: Oxford University Press.

Nucci, L. (2001). Education in the moral domain. Cambridge: Cambridge University Press.

Richerson, P. & R Boyd. 2001. “The Evolution of Subjective Commitment to Groups: A Tribal Instincts Hypothesis.” The Evolution and the Capacity for Commitment. (ed.)R. Nesse, 186-220. New York, NY: Russell Sage.

Rozin, P., Lowery, L., Imada, S., & Haidt, J. (1999). The CAD triad hypothesis: A mapping between three moral emotions (contempt, anger, disgust) and three moral codes (community, autonomy, divinity). Journal of Personality and Social Psychology, 76(4), 574-586.

Rozin, P., Haidt, J., & McCauley, C. (2000). Disgust. In M. Lewis & J. M. Haviland- Jones (Eds.), Handbook of emotions, 2nd Edition, New York: Guilford Press.

Simon, R. (1996.) Boo! Culture, experience, and the startle reflex. Oxford: Oxford University Press.

Stich, S., Fessler, D. and Kelly, D. (2009). ‘On The Morality of Harm: A Response to Sousa, Holbrook and Piazza,Cognition, 113(1): 93-97.

Turiel, E. (1983). The development of social knowledge. Cambridge: Cambridge University Press.

Washington, N. and Kelly, D. ‘Who’s Responsible for This? Moral Responsibility, Externalism, and Knowledge about Implicit Bias‘ to appear in Implicit Bias and Philosophy, Eds. M. Brownstein and J. Saul. Oxford University Press.



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