Joshua Greene and his colleagues have proposed a dual-process theory of moral decision-making to account for the effects of emotional responses on our judgments about moral dilemmas that ask us to contemplate causing direct personal harm. Early formulations of the theory contrast emotional and cognitive decision-making, saying that each is the product of a separable neural system. Later formulations emphasize that emotions are also involved in cognitive processing. I argue that, given the acknowledgement that emotions inform cognitive decision-making, a single-process theory can explain all of the data that have been cited as evidence for Greene’s theory. The emotional response to the thought of causing harm may differ in degree, but not in kind, from other emotions influencing moral decision-making.
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They also use a set of nonmoral dilemmas (e.g. scenarios that asked participants to choose whether to take the bus or the train, given prevailing time constraints). Patterns of neural activity were similar for nonmoral and for impersonal moral dilemmas.
These cognition-related areas found to be more active during contemplation of “impersonal” moral dilemmas were the right middle frontal gyrus (BA 46) and bilateral parietal areas (BA 7/40). The emotion-related areas active during “personal” moral dilemmas were the medial prefrontal cortex, Brodmann areas (BA) 9 and 10; the posterior cingulate cortex (BA 31) and bilateral angular gyrus (BA 39). In their second paper, some areas of the posterior cingulate (BA 31) were more active during contemplation of personal moral dilemmas, while others (BA 23, 31) were more active when impersonal moral dilemmas were presented.
Greene et al. originally interpret these reaction time results as further evidence for the operation of two distinct processes, but later retract this claim in response to a reanalysis of their data by McGuire et al. . (See  for Greene’s response regarding the implications of the reanalysis. I discuss this exchange further later on in this paper.) Berker  also provides important criticism of the reaction time data.
Greene et al. refer to “cognitive” versus emotional representations and “cognitive” versus emotional processes. They don’t elaborate on this terminology but, roughly, it seems that “cognitive” processing is carried out over “cognitive” representations (with their attached affective states), while emotional processing occurs over intrinsically-emotional representations.
The idea that the emotion system functions like an alarm bell is first introduced in . Greene also discusses here the idea that “cognitive” representations are inherently neutral and are, or perhaps must be, contingently attached to emotional representations in order to exert any influence on behavior.
Reflecting his main interests in his paper, Kahane characterizes the two versions of the theory as making claims about deontological versus utilitarian judgment, but I will use the distinction without reference to Greene’s conclusions about the relationship between his dual-process theory and normative ethical theories.
Beyond the dual-process theory, the opposition between cognition and emotion has also been criticized. For a recent overview of this issue, see .
Whether a dilemma counted as easy or difficult for a particular participant depending on the time they took to respond whether the action was morally appropriate or inappropriate. Greene et al. assumed that a longer reaction time indicated a more difficult decision. The infanticide dilemma was easy for the majority of participants, while the crying baby dilemma was difficult for most people. It should also be noted that there was less agreement among the responses to difficult than to easy dilemmas.
In fact, there is another important difference between this study and that of Koenigs et al.; Ciaramelli et al. used a random selection of dilemmas from Greene’s set), but did not distinguish between high conflict and low conflict dilemmas in their analysis. (Thank you to an anonymous reviewer of this paper for pointing out this difference.) Recall that Greene’s original set of personal moral dilemmas included “low conflict” ones in which participants were asked whether they would cause personal harm in scenarios in which that harm did not prevent greater harm to others (e.g. abandoning a baby you did not want to care for). Since Koenigs et al. found statistically significant differences between the groups only with regard to high conflict dilemmas, it may be that Ciaramelli et al. did not find a significant difference between the groups because they analyzed all of the (high and low conflict) personal moral dilemmas together.
It is easy to see why Cushman et al. were misled, given the way that the study results were reported. Despite failing to find a statistically significant difference in the responses each group gave to personal moral dilemmas, Ciaramelli et al. still conducted post hoc analyses “for completeness.” On the basis of these post hoc results, they concluded that “patients were faster and more inclined than normal controls to authorize moral violations in personal moral dilemmas [emphasis mine]” [20, p. 88]. Actually, their data only demonstrate a statistically significant difference in the speed of responses.
This observation may be difficult to reconcile with the suggestion, above, that these patients retain knowledge of social norms.
Damasio explains his choice of terminology: “Because the feeling is about the body, I gave the phenomena the technical term somatic state…and because it ‘marks’ an image, I called it a marker…I use the term somatic in the most general sense (that which pertains to the body) and I include both visceral and nonvisceral sensations when I refer to somatic markers” [22, p. 173]. Damasio’s proposed mechanism for attaching emotional significance to possible outcomes is therefore based on a general ability to read bodily reactions, whereas Greene’s emotional process is explained in terms of a dedicated neural system.
Damasio’s use of the phrase “alarm signal” should not be confused with Greene’s “alarm bell” terminology. Somatic markers are not, as the next paragraph will show, responses to very specific problems like the thought of causing personal harm; they are attached to all sorts of cognitive representations.
I will return to this point later in the paper.
Bartels follows Greene in identifying emotional/intuitive judgments with deontology and deliberate “cognitive” judgments with utilitarianism. Because I am not concerned here with the extension of Greene’s dual-process theory to normative moral theories, I will not consider this aspect of Bartels’s paper.
Oddly, in a later paper these authors seem much more sympathetic to Greene’s theory, though they do not address the reason for this change . The primary conclusion of this second paper is that the distinction between personal and impersonal moral dilemmas is, contra McGuire et al. , reliable. Since Greene’s own discussions of the dual-process theory have moved away from this distinction, I will not discuss the second paper by Moore et al. any further.
Evolutionary psychology is itself controversial. (For criticisms, see (; ), among others.) I will not address this controversy here, but will simply examine whether Greene’s hypothesized module meets the criteria for modularity that have been set out by evolutionary psychologists themselves.
Greene’s suggestion that the system responds to perceived unfairness comes from work by Sanfey et al.  that shows that perceived unfairness is associated with activation in brain areas similar to those activated by the footbridge problem. See Crockett et al.  for an alternative explanation of the emotional response to unfairness.
Greene describes the emotional response as modular in the context of his “modular myopia” hypothesis. This hypothesis is one of the major new theoretical developments presented in the book. Briefly, the “myopia” of the emotional response module occurs because it is not able to see harmful side effects of contemplated actions (thus explaining why the switch dilemma does not trigger a strong emotional response). Because this new development does not change the dual-process theory itself, I do not consider it further in this paper.
Fodor draws a distinction between informational encapsulation (other cognitive processes do not influence the operation of the module) and inaccessibility to central processes (the operation of the module is not open to introspection). I have suggested here that Greene thinks that both of these are true of the emotional process: the first because the alarm bell is nonnegotiable and the second because of moral dumbfounding.
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Work on this paper was supported by a National Endowment for the Humanities Summer Stipend #FT-59,871-12. I am grateful for feedback on earlier versions of this paper provided by Ginger Hoffman, Dale Miller, and the participants at the second annual New Scholars in Bioethics (NSiB) Symposium: Kirstin Borgerson, Danielle Bromwich, Michael Garnett, Douglas MacKay, and Joseph Millum. Three anonymous reviewers for this journal also provided extremely valuable feedback.
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Bluhm, R. No Need for Alarm: A Critical Analysis of Greene’s Dual-Process Theory of Moral Decision-Making. Neuroethics 7, 299–316 (2014). https://doi.org/10.1007/s12152-014-9209-0
- Dual-process theory
- Joshua Greene
- Moral decision-making