One of our readers has suggested that one of us post something on last Sunday’s New York Times Magazine piece on stem cells and animals.  It seems that scientists have now been injecting human stem cells into some animals to figure out the ways in which the cells might differentiate and develop, and so, as with any new medical technology or procedure, certain ethical questions are raised.  Combining the cells of any two distinct species creates what is known as a “chimera,” and so when these human cells are injected into the brain of a mouse, say, we’ve got a mouse/human chimera on our hands (perhaps literally).  As it’s put in the article:

Few people argue that all experiments mixing human and animal material should be banned outright.  But where should the lines be drawn?  “Some scientists are completely upset with even a single human cell in a monkey brain,” says Evan Snyder, a neurobiologist who has conducted chimeric experiments with Redmond.  “I don’t have problems with putting in a large percentage of cells – 10 or 20 percent – if I felt it could help a patient.  It comes down to what percentage of human cells starts making you squirm.”

But what precisely are the ethical issues involved here?  Believe it or not, what seems to be taken most seriously in defining the ethical issues is the aforementioned what-makes-you-squirm condition, known officially (I kid you not) as the “yuck factor.” 

Again, to quote from the article:

The man most identified with that term, Dr. Leon Kass, the bioethicist and current chairman of the President’s Council on Bioethics, is of the opinion that widespread feelings of repugnance may be an alarm that something is morally wrong, even if you are not able to articulate precisely why.  The mouse [with a partly human immune system] and the senator [with a partly porcine heart] may not trigger a yuck because they look just like a rodent and a person.  But what about a normal-looking mouse with a headful of human brain cells or a human-animal embryo that is only briefly alive and never seen?

I must confess to being less interested in the so-called ethical concerns involved in chimeras than I am in exploring the nature of the “yuck factor.”  Should “feelings of repugnance” play a role in moral deliberation and the attempts to arrive at moral verdicts?  One thought might be that yes, because we’re on new ethical terrain, we should take whatever we can in the way of moral data, and repugnance at least provides us with that.

There are some obvious worries with doing so, though, not the least of which being that, if this is all we have to go on, then we’re going to wind up with some seriously intractable disagreement, because there are some states of affairs about which people would disagree wildly in their degrees of squeamishness.  Professional philosophers, for the most part, have had their capacity for squeamishness greatly reduced, I suspect, after years of considering rather crazy intuition-pumps and following implications to absurd ends, so their reaction to the thought of a monkey/human chimera may be more along the lines of detached curiosity than horrified disgust (or at least the former is how I would likely react, mixed in with a dash of enthusiasm).  But this is just a particularized form of the standard worry about appealing to intuitions.  Nevertheless, it’s particularly worrisome when repugnance is included as an important feature of moral discourse at the public policy level.

In addition, it’s entirely unclear that the “yuck” feeling is an indicator of either (a) a moral worry, or (b) a moral worry.  With respect to (a), we tend to experience repugnance at all sorts of states of affairs, so why think it tracks a specifically moral concern?  For example, I may be feel a “yuck” when you traipse around barefoot and I see a bit of dirt underneath your toenails.  I’m obviously not undergoing the basis of a moral judgment, though.  As for (b), the self-aware homophobe may still undergo the “yuck” factor when seeing two men kiss, despite his full-fledged affirmation that there’s nothing wrong – morally or otherwise – with that action.  Given these facts, then, why think that a “yuck” feeling is, or ought to be, relevant to specifically moral deliberation and discourse?

Perhaps, though, if we take seriously that our “yuck” feelings are just a starting point, we can at least take them into account as one of many possible instances of moral data entering into the deliberative mix.  But should we even allow this?  My main worry in doing so has to do with Kass’s claim that “widespread feelings of repugnance may be an alarm that something is morally wrong, even if you are not able to articulate precisely why.”  This claim immediately reminded me of the work of Jonathan Haidt, a psychologist at the University of Virginia, who has written a powerhouse article called “The Emotional Dog and its Rational Tail” [Psychological Review 108:4 (2001): 814-834], in which he summarizes a load of recent psychological literature on moral decision-making, and suggests that most of the time when we express some deep-seated emotional reaction (like “yuck”) to a morally charged situation, we are, ultimately, often drawing on an intuition that reflects how others we trust would react to the situation (this is what he calls the “social intuitionist” model of moral judgment).  For example, many studies show that, when people are asked about certain harmless but morally charged situations involving, say, incest between a brother and sister, they’ll respond that it’s wrong, but when pressed for reasons they’ll eventually say something like, “I don’t know, I can’t explain it.  I just know it’s wrong” (p. 814).  Haidt suggests – and he seems quite right here – that when faced with morally charged situations, people simply have an intuition, which then produces a judgment about its rightness/wrongness, and then they provide, when pressed, public reasons to try and rationalize the judgment made.  The public reasoning, then, doesn’t serve to produce and support the moral verdict; instead, the verdict comes first.  The function the public reasoning does serve, however, is that of influencing the intuitions, and thus moral verdicts, of other people.  But here’s the kicker: it doesn’t do so via its actual reasons; instead, it does so because of whose mouths emit it.  This is the “I agree with people I like” heuristic, suggests Haidt: “If your friend is telling you how Robert mistreated her, there is little need for you to think systematically about the good reasons Robert might have had.  The mere fact that your friend has made a judgment affects your own intuitions directly . . .” (p. 820).  So people’s intuitions are affected directly, not by any moral reasons espoused, but simply by who the espouser is.  (Incidentally, these findings occur across the board, except in one group.  Guess which one?  See the answer below.)

Disgust/repugnance is a particularly contagious emotion.  Imagine being in a situation with your good friends, and you come across some activity at which all of your friends immediately express strong disgust.  It would be enormously difficult for you to resist experiencing the same emotion.  It is in this respect, I suspect, that disgust is much like laughter and yawning: it serves as a form of social glue, a deep-seated form of bonding selected for a very long time ago.  I have no doubt that it is utterly pre- or non-rational, though: what one will feel “yuck” towards will either be indicative of a primal aversion to something related to what we ought to avoid ingesting (e.g., rotten foods, excrement), or a function of what others we trust express disgust towards.  In neither case, though, should the reaction necessarily play any role in contributing to public policy discussions of specifically moral matters.

What’s worrisome about this view, though, is that it applies to moral verdicts generally.  It’s not just disgust that’s at the root of our moral verdicts, after all; it’s also a variety of other emotions that drive moral deliberations, and deliberation generally.  Indeed, this is one of the most important findings of neuropsychology these days.  So I’m not sure what the lesson is that we should draw from all this.  Should we simply not trust our moral verdicts, insofar as they are typically based on intuitions dependent either on the emotions we simply find ourselves having or on the emotional bonds we happen to have to certain others?  Or should we simply accept that these are the ways in which our brains operate, this is what our moral verdicts amount to, and then exploit that knowledge in the public domain to achieve consensus on the moral conclusions we want (via, say, a kind of public rhetoric/propaganda)?

I suppose, then, that there are a number of issues I’d like to hear from you on, based on the preceding rambling diatribe.  First, what role, if any, ought the “yuck factor” play in public (or even private) moral discourse?  Second, is there a way to distinguish disgust/repugnance from the other emotions that clearly play a role in our moral verdicts?  Third, what, if anything, should be done about the way in which emotions generally feed into our moral “deliberations” and verdicts?  Fourth, what precisely are the ethical issues involved in the creation of chimeras?  (Sorry if that last question sounds like a nonsequitur, despite being the general motivation for the post itself.)

Oh, and what group is the exception to Haidt’s descriptions?  That’s right: philosophers.  But before you pat yourself on the back as being part of the one group that gets things right, you might consider the alternative possibility that you’re instead just deeply flawed humans….

6 Replies to “Chimeras and the “Yuck Factor”

  1. David,
    I like your hunch that there might be an important distinction between relying on feelings of disgust in matters of public moral discourse and relying on it in matters of private discourse. But perhaps the more important distinction is between its use in everyday moral reasoning and its use in more thoroughgoing reflection where an important value is the articulation of reasons for particulars point of view (such as public discourse about policy, to be sure, but also private reflection on some weighty matter, class discussions, and so on). Let me explain.
    There seem to be a great number of people these days — philosophers, psychologists, and neurophysiologists — who insist that we are really utterly dependent on our emotional reactions to navigate our way through the day, helping us to resolve moral and prudential dilemmas without having to think them through — that is, giving us good guidelines for action without requiring us to articulate the reasons for those guidelines (just as Kass suggests can be true of disgust). A good neurophysiological defense of this, by the way, is Antonio Damasio’s Descartes’ Error (a very accessible book) as well as his Looking for Spinoza. Apparently people whose emotional reactions are profoundly impaired, whether by stroke or (in one famous case) by having a bar stuck through the head, have a great deal of trouble just getting by, even when they otherwise perform well on other sorts of cognitive tests.
    And it’s really not hard to imagine how this could be. There simply isn’t enough time in the world to think through all of the relevant moral options at any given moment, and it seems to be our visceral feelings, and not just some affect-less “habits of thought,” that help us through, not only by highlighting the morally preferable options at stake, but by helping us to recognize when morally salient issues arise in the first place.
    So it really is inevitable, I think, that our emotions will feed into our deliberations, at least into the everyday and necessarily circumscribed deliberations that we must engage in. That said, however, there is still ample room to argue that some emotions are better for these ordinary purposes than others. Nussbaum, who has a great deal to say in favor of compassion and such, also takes Kass to task for his reliance on disgust and the yuck factor. She’s not always charitable to Kass, I think, but her general argument is interesting. In a nutshell, she thinks disgust is misapplied when taken as a guideline for moral deliberation, because it really gets its content (Nussbaum is a cognitivist on the emotions — that is, the emotions *are* judgments of a certain kind) from aspirations to invulnerability and worries about contamination that no longer apply, at least not in this day and age. There was a time when it had a certain instrumental value in keeping primitive people away from bad things, but these days we no longer depend upon disgust for that, and oftentimes our disgust misjudges what those bad things really are.
    But really the more interesting question, then, is whether we should rely on (some) emotions in more thoroughgoing forms of moral justification. There seem to be some obvious senses in which we really must, at least if we are subjectivists about human welfare, and think that part of what makes X a primary good is that people find it to be good for them (which surely requires a test of emotion, in my view). But this might be trivial for your purposes, no?

  2. Fascinating topic. I just have one small point to make, then a lot of thinking to do. I don’t think most people are in any danger of confusing an ordinary sense of disgust with a quite different emotion, morally-tinged repugnance. I can get disgusted at spoiled food, but nothing’s immoral about that. I can get disgusted at a hideously deformed person, but not think that person is evil–not even lean in that direction. At least I think I can. Others’ thoughts?

  3. First off, it seems to me that to make any sense at all of disgust playing a justificatory role in moral epistemology we have to think of it (and other cognate attitudes, emotions, etc.) as being a cognitive state, some sort of judgment or belief-like state with specific intentional content. Otherwise, it’s hard to see how the emotions can be truth-apt, as Crispin Wright might say.
    I’d say it’s unlikely we should “rely on” such emotions, since they clearly can be mistaken. What’s unsettling about Kass’ view of the matter is his willingness to let ‘yuck’ go unchallenged by allowing the content of the judgment to go unarticulated. If the idea is that such emotions-cum-judgments are inputs into moral deliberation, that seems unobjectionable. But Kass seems to think they have prima facie moral authority, and something more besides. That strikes me as an apology for unreflective moral blindness and prejudice.
    Heath – You’re right with your examples. But it’s a little harder to see the difference between disgust and the “moral emotion” of repugnance at work in the actual cases in which Kass (and others) invoke it. That is, the ‘yuck’ people feel about incest, homosexuality, cloning, and the like seems to be both moral and, I don’t know, visceral or aesthetic. The question is which is leading and which is following: Is the feeling of disgust grounded in some judgment of wrongness, or vice versa? Kass’ willingness to allow the basis for such feelings of disgust and repugnance to go unarticulated or unanalyzed makes me suspect the latter, which makes these judgments shaky at best as reliable moral sentiments.

  4. Thanks for the very thoughtful comments. First, to Justin, yes, I’m very much aware of the work of both Damasio and Nussbaum on these issues. I think Damasio (along with others) is quite correct about the importance of emotions to moral deliberation and deliberation generally. My question, then, was whether or not there was a way to make a distinction between the disgust/repugnance emphasized by Kass, and the other emotions that clearly feed into moral deliberation. The Nussbaum attempts you cite fail to do so, it seems. For one thing, where the emotion originally got its content (via worries about vulnerability and contagion, say) seems neither here nor there with respect to its current role in moral deliberation. Second, the other, more “acceptable,” emotions as well, I’m sure, got their content in ways similar to disgust, so even if their content is more closely related to their current deployment than that of disgust, if we are focused solely on the where and the ways they got their content originally, then there’s no distinction of any importance between disgust and the other emotions. (And so see my dilemma below.)
    Heath, one might hope that there’s a way to preserve the distinction you talk about, but I’m even more of a pessimist than Michael on this score. He thinks the main worry is about a lack of distinction between disgust and morally-tinged repugnance in the cases *Kass* cites, but I tend to believe we can’t run that distinction very far (or successfully) *at all*. At least in terms of the qualia and the content of the judgment, for long-term vegetarians, to take just one example, there seems to be no difference between their disgust at the smell/look of a steak on the barbecue and anyone else’s disgust at rotten food. And while it’s precisely qualia and content that Kass and others want to focus on (thus Michael’s worry), the way in which disgust comes up in everyday morally-tinged contexts leads me to believe that the distinction you cite is conflated/ignored most of the time. Disgust at the thought of homosexual (male) activity seems clearly to operate at the level of a fundamental *natural* datum for most folks (precisely along the lines of rotten food) that’s then trotted out as the basis for a moral judgment (so this is a case in which there’s a distinction cited, I suppose, that’s completely backwards and then employed in a version of the is/ought fallacy!). On the other hand, folks who live downwind from a sewage treatment facility may experience disgust at the smells that they nevertheless treat with a distinctly moral tincture.
    Finally, Michael, I’m not sure what to think about Kass and the relation between judgments of wrongness and disgust. He claims that the feeling of disgust is indicative of wrongness, which implies to me that he believes disgust is just a signpost for a deeper judgment (albeit one we might not be able to articulate). This would allow him to avoid your worries about the “shakiness” of the moral judgments, but perhaps at the cost of the psychological facts of the matter, if Haidt is right.
    So I guess what I’ve been suggesting is a kind of dilemma. Either we think, along with Kass, that disgust is really grounded in an antecedent moral judgment, in which case he’s just wrong about the psychology, or we agree with Haidt that disgust is antecedent to the moral judgment (typically, for most folks), in which case, since we can’t find a viable distinction between disgust and the rest of the moral emotions, our worries about appealing to disgust in moral deliberation carry over to the kinds of emotion ordinarily feeding into moral deliberation as well.

  5. David,
    Thanks for the clarification/reminder/slap-on-the-head. I have to admit the dilemma seems relatively apparent now that I look back at your original post, although the first time through I thought it was something more of an open bag.
    I’m tempted to say that Kass is right to think that disgust is grounded in a judgment, but mistaken in thinking that it is grounded in a *moral* judgment. That mistake comes in at a higher order, when he concludes, in retrospect, that his initial feeling of disgust was indicative in some way of a moral judgment or moral sense.
    If I may say so, however, I get the impression that you do not really see this is a dilemma at all, but rather gladly grab onto Haidt’s horn come what may, and are much more interested in thinking about the fallout from that view. In other words, what, given the fact of a great deal of poorly-informed moral judgment, influenced by a kind of emotional contagion and such, should we do about it? The unhappy upshot of Haidt’s view is the dark picture of standard moral reasoning that we would have to accept. The unhappy upshot of Kass’s view is that it contradicts a mountain of evidence gathered by Haidt. Is that right?

  6. Yes, Justin, you’ve put your finger on precisely the position I’m saddling myself with: Kass can’t be correct if he thinks our emotional reactions are simply indicators of more deeply-held-but-unarticulated moral judgments, simply because of the (ever-growing) mountain of data otherwise. So then the question really becomes (a) if we’re worried about the picture in which our moral judgments depend on disgust/repugnance, but (b) there’s no relevant distinction between disgust/repugnance and other emotions that feed into our moral deliberations (in terms of either qualia or content), then (c) our worries about disgust and its role in public policy would seem to carry over without remainder to moral deliberation more generally.

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