Here’s a draft of the section of “Experimental Moral Philosophy,” (for the Stanford Encyclopedia of Philosophy) on the emotions that I just drafted. As always, questions, comments, suggestions, and criticisms are most welcome.
Experimental inquiries into morality and emotion overlap in myriad, distantly-related ways. We can only hope to gesture at many of the interesting questions that have been investigated in this context. For instance, are moral judgments always motivating? In other words, does it follow that, insofar as you judge that x is morally right (wrong), you are – perhaps only defeasibly, but to some extent – motivated to x (avoid xing)? An affirmative answer is often labeled “internalist,” whereas a negative answer is labeled “externalist.” Emotions are intrinsically motivational, so if experimental investigation could show that emotion was implicated in all moral judgments, that would be a point in favor of internalism. Another question we will not discuss in depth: is emotionally-driven reasoning in general better or worse than “cold,” affectless reasoning? Greene et al. (2001, 2004) seem to presuppose that cold reasoning is typically or even always better, but we see little reason to make such a sweeping judgment.
Instead of trying to address all of the relevant questions, we focus on a particular application based on what have come to be known as dual-system models of cognition, reasoning, decision-making, and behavior. While the exact details of the two systems vary from author to author, the basic distinction is between what Daniel Kahneman calls System 1, which is fast, automatic, effortless, potentially unconscious, often affect-laden, and sometimes incorrigible, and System 2, which is slow, deliberative, effortful, typically conscious, and associated with the subjective experience of agency, choice, and concentration (2011, pp. 20-21). Whereas System 2 exhibits a degree of functional unity, System 1 is better conceived as a loose conglomeration of semi-autonomous dispositions, states, and processes, which can conflict not only with System 2 but also with each other.
The dual-system approach has been employed by various experimental moral philosophers and experimental moral psychologists, including Joshua Greene (2008, 2012), Jonathan Haidt (2012; Haidt & Björklund 2008), Joshua Knobe (Inbar et al. 2009), Fiery Cushman (Cushman & Greene forthcoming), and Daniel Kelly (2011). We will focus in particular on one process that relies heavily on System 1, disgust, to show what experimental moral philosophy of the emotions can do.
Disgust is an emotion that seems to be unique to human animals. It involves characteristic bodily, affective, motivational, evaluative, and cognitive patterns. For instance, someone who feels disgusted almost always makes a gaping facial expression, withdraws slightly from the object of disgust, experiences a slight reduction in body temperature and heart rate, and feels a sense of nausea and the need to cleanse herself. In addition, she is motivated to avoid and even expunge the offending object, experiences it as contaminating and repugnant, becomes more attuned to other disgusting objects in the immediate environment, is inclined to treat anything that the object comes in contact with (whether physically or symbolically) as also disgusting, and is more inclined to make harsh moral judgments – both about the object and in general. There are certain objects that basically all normal adults are disgusted by (feces, decaying corpses, rotting food, spiders, maggots, gross physical deformities), but there is also considerable intercultural and interpersonal variation beyond these core objects of disgust, including in some better-studied cases cuisines, sexual behaviors, out-group members, and violations of social norms. Furthermore, the disgust reaction is nearly impossible to repress, is easily recognized, and – when recognized – empathically induces disgust in the other person.
In a recent monograph, Kelly (2011) persuasively argues that this seemingly bizarre combination of features is best explained by what he calls the “entanglement thesis” (chapter 2) and the “co-opt thesis” (chapter 4). First, the universal bodily manifestations of disgust evolved to help humans avoid ingesting toxins and other harmful substances, while the more cognitive or symbolic sense of offensiveness and contamination associated with disgust evolved to help humans avoid diseases and parasites. According to the entanglement thesis, these initially distinct System 1 responses became entangled in the course of human evolution and now systematically co-occur. If you make the gape face, whatever you’re attending to will start to look contaminated; if something disgusts you at a cognitive level, you will flash a quick gape face. Second, according to the co-opt thesis, the entangled emotional system for disgust was later recruited for an entirely distinct purpose: to help mark the boundaries between in-group and out-group, and thus to motivate cooperation with in-group members, punishment of in-group defectors, and exclusion of out-group members. Because the disgust reaction is both on a “hair trigger” (it acquires new cues extremely easily and empathically, p. 51) and “ballistic” (once set in motion, it is nearly impossible to halt or reverse, p. 72), it was ripe to be co-opted in this way.
Dan Kelly’s “Yuck!”
If Kelly’s account of disgust is on the right track, it seems to have a number of important moral upshots. One of the more direct consequences of this theory is what he calls “disgust skepticism” (p. 139), according to which the combination of disgust’s hair trigger and its ballistic trajectory mean that it is extremely prone to incorrigible false positives that involve unwarranted feelings of contamination and even dehumanization. Hence, “the fact that something is disgusting is not even remotely a reliable indicator of moral foul play” but is instead “irrelevant to moral justification” (p. 148).
Many theories of value incorporate a link between emotions and value. According to fitting-attitude theories (Rönnow-Rasumussen 2011), something is bad if and only if there is reason to take a con-attitude (e.g., dislike, aversion, anger, hatred, disgust, contempt) towards it, and good if and only if there is reason to take a pro-attitude (e.g., liking, love, respect, pride, awe, gratitude) towards it. According to response-dependence theories (Prinz 2007), something is bad (good) just in case one would, after reflection and deliberation, hold a con-attitude (pro-attitude) towards it. According to desire-satisfaction theories of well-being (Heathwood 2006), your life is going well to the extent that objects towards which you harbor pro-attitudes are promoted and preserved, and objects towards which you harbor con-attitudes suffer or are harmed. If Kelly’s disgust skepticism is on the right track, it looks like it would be a mistake to lump together all con-attitudes. Perhaps it still makes sense to connect other con-attitudes, such as indignation, with moral badness, but it seems unwarranted to connect disgust with moral badness. Thus, experimental moral philosophy of the emotions leads to a potential insight into the evaluative diversity of con-attitudes.
Another potential upshot of the experimental research derives from the fact that disgust belongs firmly in System 1: it is fast, automatic, effortless, potentially unconscious, affect-laden, and nearly incorrigible. Moreover, while it is exceedingly easy to acquire new disgust triggers whether you want to or not, there seems to be no reliable way to de-acquire them, even if you want to. Together, these points raise worries about moral responsibility. It’s a widely accepted platitude that the less control you have over your behavior, the less responsible you are for that behavior. At one extreme, if you totally lack control, many would say that you are not responsible for what you do. Imagine an individual who acts badly because he is disgusted: he gapes when he sees two men kissing, even though he reflectively does not endorse homophobia; the men see this gape and, understandably, feel ostracized. Would it be appropriate for them to take up a Strawsonian (1962) reactive attitude towards him, such as indignation? Would it be appropriate for him to feel a corresponding attitude towards himself, such as guilt or shame? Of course, if his flash of disgust is something that he recognizes and endorses, the answers to these questions may be simpler, but what are we to say about the case where someone is, as it were, stuck with a disgust trigger that he would rather be rid of? We will not try to answer this question here; instead, we intend it to show that, while experimental moral philosophy of the emotions may provide new insights, it also raises thorny questions.
Cushman, F. & Greene, J. (forthcoming). Finding faults: How moral dilemmas illuminate cognitive structure. Social Neuroscience.
Greene, J., Nystrom, L., Engell, A., Darley, J., & Cohen, J. (2004). The neural bases of cognitive conflict and control in moral judgment. Neuron, 44, 389-400.
Greene, J., Sommerville, B., Nystrom, L., Darley, J., Cohen, J. (2001). An fMRI investigation of emotional engagement in moral judgment. Science, 293, 2105-2108.
Greene, J. (2008). The secret joke of Kant’s soul. In W. Sinnott-Armstrong (ed.), Moral Psychology, volume 3, pp. 35-80. Cambridge: MIT Press.
Greene, J. (2012). Reflection and reasoning in moral judgment. Cognitive Science 36:1, 163-177.
Haidt, J. (2012). The Righteous Mind: Why Good People are Divided by Politics and Religion. New York: Pantheon.
Haidt, J. & Björklund, F. (2008). Social intuitionists answer six questions about moral psychology. In W. Sinnott-Armstrong (ed.), Moral Psychology, volume 2, pp. 181-218. Cambridge: MIT Press.
Heathwood, C. (2006). Desire satisfaction and hedonism. Philosophical Studies, 128:3, 539-463.
Inbar, Y., Pizarro, Knobe, J. & Bloom, P. (2009). Disgust sensitivity predicts intuitive disapproval of gays. Emotion, 9:3, 435-443.
Kahneman, D. (2011). Thinking, Fast and Slow. New York: Farrar, Straus, & Giroux.
Kelly, D. (2011). Yuck! The Nature and Moral Significance of Disgust. Cambridge: MIT Press.
Nichols, S. (2004). Sentimental Rules. Oxford University Press.
Prinz, J. (2007). The Emotional Construction of Morals. Oxford University Press.
Rönnow-Rasumussen, T. (2011). Personal Value. Oxford University Press.
Strandberg, C. & Björklund, F. (forthcoming). Is moral internalism supported by folk intuitions? Philosophical Psychology, 1-17.
Strawson, P. (1962) Freedom and resentment. Proceedings of the British Academy, 48, 1-25.
 See Nichols (2004, ch. 5) and Strandberg & Björklund (forthcoming) for an experimentally-motivated argument against internalism.
 See Kelly (2011, especially chapter 1) for a comprehensive literature review