“Both of Us Disgusted in My Insula”: Mirror Neuron Theory and Emotional Empathy
In a report of the results of an experiment pertaining to a common neural basis for seeing and feeling the emotion of disgust, the claim is made that, just as we have mirror-neuron mechanisms for understanding other people’s intentional actions, so we have mirror-neuron mechanisms for understanding or empathizing with other people’s emotions. The article was published in 2003 by a group of scientists that included first-author Bruno Wicker and co-authors Giacomo Rizzolatti and Vittorio Gallese, the last two being well known as members of the research team that discovered mirror neurons in monkeys. I consider their paper a telling example of what can go wrong in emotion research today, and in the following discussion I shall try to say why.1
A mirror neuron is a neuron that fires both when an animal enacts a movement and when that animal merely observes the same action by another (especially a con-specific). In other words, mirror neurons appear to “mirror” the behavior of another animal by a kind of motor simulation or motoric resonance. Mirror neurons were first detected in the 1990s in experiments using electrodes directly implanted in the pre-motor cortex of the macaque monkey. Although mirror neurons are often assumed to exist in humans and other species, the evidence is scant.2 In humans, for example, the only published direct evidence of mirror neuron activity exists in the form of single-neuron electrode recordings from the brains of epileptic patients and even that evidence is equivocal.3
From the start, the function of mirror neurons has been the topic of much speculation and controversy. Many researchers have claimed that mirror neurons provide a mechanism for an animal’s ability to grasp the motor-intentional actions of others without the intervention of higher cognitive or sensory processes. Dysfunction in the mirror neuron system is also thought to explain mind-reading failures associated with autism. Gallese and art historian David Freedberg have recently applied the idea of mirror neurons to the field of neuroaesthetics by claiming that our empathic responses to works of art as well as to everyday images depend on the activation of embodied, non-cognitive mirror-neuron mechanisms.4 Freedberg and Gallese thus follow the trend in the neurosciences to expand the role of mirror neurons to include the capacity for emotional empathy.5
In their 2003 article, Wicker and his group described the results of a Functional Magnetic Resonance Imaging (fMRI) study in which experimental subjects were asked to inhale odorants selected to produce strong feelings of disgust. The same subjects were also asked to observe video clips of other individuals exhibiting or showing the facial expression of disgust. The scientists reported that the same sites in the anterior insula (and to a lesser extent in the anterior cingulate cortex) were activated both when the experimental subjects themselves experienced disgust and when they observed the filmed expressions of disgust on the faces of others.6 The researchers therefore concluded in reference to the mirror-neuron matching system that, “just as observing hand actions activates the observer’s motor representation of that action, observing an emotion activates the neural representation of that emotion. This finding provides a unifying mechanism for understanding the behavior of others” (“BUD,” 655). The study by Wicker and his team has generated considerable interest in the neuroscientific community (a recent Google search indicates that the paper has now been cited in over 900 research articles). In subsequent publications, Rizzolatti, Gallese, Keysers and others have cited Wicker et al.’s experiment on disgust as confirming the idea that there is a common neural basis for emotional empathy.7 The experiment by Wicker and his group has also provided confirming evidence for Alvin I. Goldman’s influential approach to the “problem of other minds.” In his 2006 book, Simulating Minds, Goldman begins his review of the empirical evidence supportive of his Simulation Theory of mindreading by focusing on the “low-level” task of recognizing the emotional expressions of others because, as he observes with reference to the findings of Wicker et al. and those of others, the case for simulation here is “very substantial.”8
The Wicker Experiment In Detail
Let me begin by providing some details about the Wicker experiment. First, the experimenters recruited from a Marseille theater school six actors (male and female) who agreed to be filmed while smelling either neutral, or pleasant, or unpleasant odors. The actors were presented with a glass containing either pure water (for the neutral expression), water with an added pleasant odor (perfume designed to produce the pleased expression), or water with an added unpleasant odor (the content of “stinking balls” from a local toy store designed to induce the disgust expression). The actors were asked to display the relevant emotional reactions in a “natural but clear way.” Each emotional reaction was filmed three times for each actor, and the “most natural example” was selected by one of the experimenters. These filmed enactments served as the visual “stimuli” for the experiment that followed.
The experiment itself was conducted with fourteen males, each of whom was asked to participate in two “visual runs” and two “olfactory runs” while undergoing fMRI. In the “visual runs” the participants passively viewed the film clips that had been made of the actors smelling the contents of the glass. The participants were not informed of the aim of the study, and were not explicitly instructed to empathize with the actors. In the “olfactory runs” the participants themselves inhaled the same pleasant or disgusting or neutral odors that had been smelled by the filmed actors.
The central finding of Wicker and his team was that the anterior insula was not activated during the participants’ observation of happy expressions or during their experience of pleasant odors. But it was activated both during their observation of the actors’ disgusted facial expressions and during the feeling of disgust evoked in the participants themselves when they smelled the foul odors. The investigators suggested that two different hypotheses might explain our ability to recognize and understand emotions in other people. According to the “cold” hypothesis, we recognize the affects of others by using our perceptual and cognitive mechanisms without ourselves experiencing or sharing the same emotions and without activating the same causal mechanisms. But Wicker’s group claimed that their findings appeared to confirm the “hot hypothesis” according to which observing the emotions of others automatically generates the same emotion in ourselves because of a shared neural basis for seeing and feeling. In the case of disgust, the authors stated, “this automaticity may explain why it is so hard to refrain from sharing a visceromotor response (e.g., vomiting) of others when observing it in them” (“BUD,” 661). The authors suggested that in evolutionary terms “hot” activation is likely to be the oldest form of emotion understanding, permitting a form of primitive empathy that may protect monkeys and young human infants from food poisoning even before sophisticated cognitive skills develop (“BUD,” 661).
Goldman considers Wicker’s disgust experiment an original contribution to his Simulation Theory because it provides evidence for an “Unmediated Resonance (Mirroring)” model of simulation, according to which the perception of the target’s facial expression “directly” triggers sub-threshold activation of the same neural substrate of the emotion in question. He states that this model does not require the cognitive “pretend” or “off-line” states on which higher-level mindreading is theorized to depend, but only a minimum automatic matching between the pair of emotion events in the target and the observer. “The observer’s emotional system ‘resonates’ with that of the target,” Goldman writes, “and this is the matching event on which the attribution is based.”9
Wicker’s et al.’s experiment and the conclusions drawn from it presupposed a set of theoretical and methodological premises that are deeply entrenched in the field of emotion research today, and it is important to be clear about them from the outset. The main assumptions informing their work can be briefly summarized as follows:
1. There exists a small set of “basic emotions” (“BUD,” 658) defined as pan-cultural categories or “natural kinds.” These basic emotions are evolved, genetically hard-wired, reflex-like responses of the organism. Disgust is one such basic emotion, as are fear, sadness, anger, joy, surprise, and perhaps contempt. The evolved status of the emotions implies some degree of emotional commonality between human and non-human animals, although the similarities and differences are rarely articulated.
2. Each basic emotion manifests itself in distinct physiological and behavioral patterns of response, especially in characteristic facial expressions. When not masked by cultural or conventional requirements of display or by deliberate deception, the face “expresses” the affects, which is to say that under the right conditions facial displays are authentic “read-outs” of the discrete internal states that constitute the basic emotions.
3. The facial expressions associated with the basic emotions can be posed or portrayed by actors in a natural way so as to convey the authentic truth of the affects.
4. Each basic emotion is linked to specific neural substrates in the brain, an assumption that implies the embrace of some degree of modularity and information-encapsulation in brain functions. Whereas (at least until very recently) the amygdala has been pinpointed as the neural seat of fear, insula activation has been especially implicated in the response to facial expressions of disgust, a finding Wicker’s experiment claims not only to confirm but extend, such that the insula is activated both during the experimental subject’s observation of the facial expressions of disgust in others and during the subject’s own experience of disgust.10
5. Emotional processes occur independently of “cognitive” or “intentional” states.11 As Paul Ekman has declared: “[E]motional expressions are special . . . because they are involuntary, not intentional . . . emotional expressions occur without choice . . . we trust them precisely because they are unintended.”12 According to this view, the basic emotions do not involve “propositional attitudes” or beliefs about the emotional objects in our world. Rather, they are rapid, phylogenetically old, automatic responses of the organism that have evolved for survival purposes and lack the cognitive characteristics of higher-order mental processes. The tendency in the recent literature on empathy to distinguish between “cognitive empathy,” our ability to identify someone else’s intentional actions, and “emotional” empathy, our ability to sympathize with or match someone else’s feelings, helps reinforce a non-cognitive (or non-intentionalist) theory of the affects by suggesting that our affects occur independently of our cognitions. Wicker et al.’s definition of disgust conforms to the non-cognitive model by pigeonholing disgust as in essence a sensory or corporeal phenomenon—a point to which I will return.13 The authors explicitly present the “hot hypothesis” as a non-cognitive theory of emotional empathy.
6. Grasping another person’s emotional state is also a non-cognitive process. It’s just a matter of responding automatically to the triggering effect of another person’s facial displays. Goldman has criticized those whose view of empathy involves imputing purposive states to others (SM, 10-11). Goldman argues that the kind of low-level faced-based emotion recognition that occurs in emotional empathy recruits a simulation mechanism that operates automatically and sub-personally, without the necessity of propositional contents, desires, or beliefs of any kind. The comparative simplicity of faced-based emotion recognition, he writes in this regard, “consists in recognizing emotion types (e.g., fear, disgust, and anger) without identifying any propositional contents, presumably a simpler task than identifying desires or beliefs with specific contents” (SM, 113). On this view, reading someone’s emotional expressions has survival value and specialized mirroring mechanisms have evolved for this primitive kind of emotion detection.
Now to anyone knowledgeable about the history of research on the emotions, the assumptions I have just summarized will be familiar, belonging as they do to an emotion theory or paradigm that has had tremendous success over the last thirty years in the United States and, to a large extent, in Europe as well. Specifically, the presuppositions of Wicker and his team can be traced most directly to the work of the American psychologist Silvan S. Tomkins, and especially to that of his follower, Paul Ekman, both of whom have proposed an evolutionary-classificatory approach to the affects.14 Key features of their approach include the claim that there exists a small number of basic emotions, such as disgust, which can be defined in evolutionary terms as universal or pancultural, adaptive responses of the organism; that these emotions are discrete, innate, reflex-like “affect programs” located in subcortical parts of the brain; that the basic emotions manifest themselves in distinct patterns of physiological arousal and especially in characteristic facial expressions; that according to Ekman’s “neurocultural” model for explaining commonalities and variations in human facial displays, socialization and learning may determine the range of stimuli that can “trigger” the emotions and can moderate facial movements according to social norms or “display rules,” but that under the right conditions the underlying emotions can nevertheless leak out; and that the more complex or “higher” emotions are made up of blends of the basic emotions. This view of the emotions has been given a variety of names; in this paper I shall refer to it as the Basic Emotions View.15
A further claim associated with the Basic Emotions View, one that we have already seen in both Wicker et al.’s and Goldman’s work, is that although the emotions can and do combine with the cognitive systems in the brain, they are essentially separate processes. For Freud and the “appraisal theorists” such as Richard Lazarus, Robert Solomon, Martha Nussbaum, Phoebe Ellsworth and others, emotions are embodied intentional states that are directed toward objects and depend on our beliefs and desires. But the Basic Emotion View denies this by interpreting the affects as non-intentional responses. It thus posits a constitutive disjunction between our emotions on the one hand and our knowledge of what causes and maintains them on the other, because feeling and cognition are two separate systems. On this conceptualization, disgust does not concern the meaning of the objects or situations that disgust us but the inherent noxiousness or offensiveness of physical objects (such as animal and body wastes or contaminated foods) that are capable of automatically triggering an adaptive disgust response.
The Basic Emotions View has been extremely influential, especially because Ekman’s strategy of using pictures of posed facial expressions as “stimuli” to test the responses of subjects in experimental situations is so easy to use and conforms so well to the requirements of the newer imaging methods of research. Hundreds of experiments have now been performed using as emotional stimuli a standard set of photographs of posed expressions that Ekman and Friesen first made available for research purposes as far back as 1976.16 In order to give the appearance of greater “ecological validity” to their study, Wicker and his colleagues used moving rather than still pictures of actors posing expressions, but this does not alter the fact that their assumptions and research methods fundamentally adhere to the norms of the Basic Emotions View.
But are those assumptions and research methods valid? There are serious reasons to doubt it. Not only have appraisal theorists questioned the validity of the Basic Emotions View by emphasizing the role of perceptual-cognitive evaluation of the situation in emotional processing, for other reasons as well, it is doubtful whether the Basic Emotions View can withstand critical scrutiny.17 In recent years especially, investigators such as Alan J. Fridlund, James A. Russell, Jose-Miguel Fernández-Dols, Brian Parkinson, and Lisa Feldman Barrett have published cogent criticisms of the Ekman paradigm.18 The net result of those criticisms has been to directly challenge from within the emotion research field the empirical and theoretical validity of the Basic Emotions View. Nevertheless, for reasons I can’t examine here, that paradigm continues to dominate the field. Indeed, it currently represents the orthodox position.
Against this background, I now want to raise certain questions about Wicker et al.’s experiment and the uses to which it is being put to explain emotional empathy. I cannot do justice to the entire range of issues that interest me but will restrict myself to the following points:
1. My first question concerns the validity of the assumption by Wicker and his group that there exists a small set of basic emotions and that under the right conditions facial expressions can be viewed as involuntary readouts of internal emotional states. This is an assumption that Fridlund, Russell, Fernández-Dols, Feldman Barrett, and others have criticized. If we are to take their criticisms seriously, as in my view we must, then we need to reject the presuppositions underlying Wicker et al.’s analysis of emotional empathy. The idea that there exists a set of basic emotions, which manifest themselves in characteristic patterns of physiological reactions and facial movements has been shown to be erroneous, and the “readout” view of the affects mistaken. Not that the reader would learn anything about those criticisms from Wicker et al.’s paper, which simply ignores them. The authors’ failure to acknowledge the work of critics or to admit the existence of dissent exemplifies what I regard as a striking fact about the current situation of research on emotion, namely, that most scientists committed to the Basic Emotions View feel free to cite selectively and mention only the work of others that supports their views. The result is that objections are not allowed to disturb the investigators’ basic premises or their experimental approach. Simply put, the network of presuppositions and methods associated with the Basic Emotions View is too attractive and the laboratory methods too convenient to be given up.
2. The experiment on disgust by Wicker and his group was based on a belief central to the Basic Emotions View, namely, that under the right conditions the face reliably and sincerely reveals the truth about the subject’s “inner feelings.” Put slightly differently, the body does not lie. The facial displays performed by the actors as “stimuli” for the participants in the experiment were assumed to be authentic emotional expressions of this kind. It is because Ekman thinks that under the right conditions the face is bound to reveal the authentic truth of a person’s feelings that since 9/11 he has been developing methods of surveillance designed to read the telltale involuntary signs he believes will identify terrorists. His goal is to reassure us that we don’t have to be frightened by the tendency of human beings to dissimulate, because trained observers can be counted on to reliably distinguish authentic facial expressions from false ones, the genuine from the feigned. His speculations have recently led to his involvement with a fanciful television series, “Lie to Me,” in which the lead character, a jet-setting Ekman surrogate named Lightman, oversees a large firm of beautiful men and women, reads faces to solve crimes, and routinely makes the police and the FBI look foolish.
But what if his assurance that the face reliably divulges the truth of our emotions is false? What if, as critics have argued, there is no simple one-to-one relationship between a person’s facial behavior and his or her emotional state? What if facial displays can’t be considered simple readouts of underlying “basic emotions” because they are intentional communicative signals that aid in the negotiation of social encounters? As Fridlund has pointed out in this regard, “[A]ny reasonable account of signaling must recognize that signals do not evolve to provide information detrimental to the signaler. Displayers must not signal automatically, but only when it is beneficial to do so, that is, when such signaling serves its motives. Automatic readouts or spill-outs of drive states (i.e., ‘facial expressions of emotion’) would be extinguished early in phylogeny in the service of deception, economy, and privacy. Thus, an individual who momentarily shows a pursed lip on an otherwise impassive face is not showing ‘leakage’ of anger but conflicting intentions . . . for example, to show stolidity and to threaten” (HFE, 131-32). In short, what if deception is widespread in nature and can be advantageous for the displayer?19 Wouldn’t this imply that Wicker and his research team were wrong to take for granted the meaning of the posed facial expressions used in the experiment because they ignored the potential for a mismatch between facial displays and their subjects’ actual emotional experiences?
So confident were Wicker and his colleagues that faces normally and automatically express the truth of the hypothesized basic emotions that it did not occur to them to ask the actors what they themselves were feeling when they sniffed the various odorants. Of course, it’s possible that the actors really did feel the emotion of disgust they were exhibiting on their faces; the smell in question was selected because it was vile and was assumed to be intrinsically disgusting. But possibly they did not—to repeat, no one asked. Nor did the investigators make any effort to find out or discern whether the participants in the experiment felt disgust when they observed the actors posing facial expressions of disgust. This omission is all the more striking because, according to the “hot hypothesis,” individuals recognize emotions in others by actually experiencing the same emotions themselves. But how do we know that this was the case in the absence of any effort to find out? In the experiment by Wicker’s research group, any attempt to discern what the participants were feeling was ruled out from the start. All they were asked to do was to passively witness the actors’ facial displays or to smell the various odors themselves while submitting to brain imaging: emotion was equated with brain activation, with the result that the distinction between subjective experience and neuronal response was elided. In order to induce disgust in the participants, the investigators puffed the unpleasant and other odors into an anesthesia mask. Moreover, the subjects’ mouth and eyes were closed throughout the olfactory runs, and during the experiment itself they did not speak or report on their feelings. In other words, it’s as if the irrelevance of the subject’s subjective state was assumed from the outset.20 I could apply to the experiment what Vinciane Despret has said more generally about such methods in psychology: “The subject proves the scientist’s point so well only because the latter has managed to keep him from speaking.”21
3. My third question concerns the strategic role played in their experiment by Wicker et al.’s definition of disgust as simply and primordially a visceromotor reaction. For these authors, primitive or “core” disgust does not involve any cognitive-interpretive dimension entailing, as an intentionalist might argue, an embodied revulsion against appraised objects of various kinds, whether real or symbolic. Rather, Wicker and his team assumed that disgust is essentially a reflex response of the body to repulsive smells. The scientists treated the more familiar or ideational forms of disgust as elaborated forms of the more fundamental olfactory and gustatory reflexes that serve to protect the organism against poisoning by preventing the ingestion or inhalation of harmful substances and smells. Disgust was therefore viewed as a food-related sensation involving a reflex revulsion at the incorporation of revolting or noxious foods. On this interpretation, derived from the work of Paul Rozin, disgust just is the sensation of a bad smell or bad taste (as Rozin points out, the word dis-gust simply means “bad taste”): in human development distaste may become linked cognitively, ideationally, and symbolically to an array of non-food-related items and objects, but at its core disgust is “a type of rejection primarily motivated by sensory factors.”22 The fact that the anterior sector of the insula is an olfactory and gustatory center that appears to control visceral sensations and related autonomic responses helps support this sensory-corporeal definition of disgust (the anterior insula region is known as the “gustatory cortex”).23
One can see the point of Wicker et al.’s definition. If disgust is just a bodily sensation with visceromotor manifestations, then the subjective-experiential dimension can be collapsed into the corporeal by studying brain activation directly, without any apparent conceptual loss. If both of us are disgusted in my insula, because the activation of your insula when you experience an emotion is automatically duplicated by the activation of mine when I observe your disgust expression, then scientists don’t have to worry about what I am feeling or what you are feeling because the neural mechanism we share will tell us everything they need to know.24
But is such a reflex definition of disgust valid? Fridlund, for one, doesn’t think so. He concedes that the social disgust display resembles the protective gag reflex, but thinks it is more likely that the display is a convention or a “conversational icon,” of the kind we see when a child sticks out its tongue in a display of defiance (HFE, 120).25 Nor does he believe that the disgust face should be considered an “expression” of a basic emotion. As he puts it, the gag reflex acts “not to ‘express’ sensory disgust but to abort it. Likewise, the social display signifies not ‘you make me sick’ so much as ‘I want to do with you what I do with bad food (lest I get sick).’ It thereby denotes an intention rather than an ‘expression’ of an emotion, and is therefore better named ‘revulsion’ or even ‘rejection’ than ‘disgust’” (HFE, 121). In other words, Fridlund proposes that the disgust display should be regarded as an intentional movement subserving various social motives, which means not only that it is responsive to proximate elicitors but also that it is sensitive to those who are present, one’s aim toward them, and the nature and context of the interaction.26 He cites various experiments suggesting that facial responses to odors and tastes do not behave like simple reflexes but are influenced by the social situation in which they occur, including the presence of others.27 Research on animal signaling has also suggested that many nonhuman facial and vocal displays likewise vary with the presence of interactants and with the relationship between the interactants and the displayer (HFE, 145-152).28
Such findings are known collectively as “audience effects,” a characterization which has the virtue of drawing attention to the performative-transactional nature of facial and other displays.29 It is precisely this performative-transactional dimension that Wicker and his team ignored. In their experiment, the investigators treated both the actors and the experimental subjects or participants as if the latter were entirely alone in the room, which is to say as if they were completely liberated from the various cultural constraints that ordinarily guide people in any situation along a trajectory of social interaction with the expected and appropriate roles and expressions, with the result that they were free to exhibit their natural, innately-determined expressions. In other words, these scientists forgot that the laboratory is a social space structured by conscious and unconscious or subconscious demands and expectations, including not only those of the experimental subject but of the scientists involved as well. Fridlund has emphasized the “dramaturgical” dimension of such demands and expectations, suggesting that when subjects are asked to pose or mimic facial displays to the point of being emotionally aroused themselves, the experimenter is actually a director and the subject-actor posing the expression is a Stanislavski actor who “slips into role”: “It is the role or ‘set’ taken in the given social context that determines the emotion,” Fridlund observes in this regard, “not the facial displays themselves” (HFE, 179).
4. In the light of such considerations, which emphasize the sociality of facial displays, the decision by Wicker and his colleagues to define disgust as primordially a primitive reflex can be understood as a means of denying or suppressing the social-transactional character of the organism’s emotional reactions. It is all the more interesting, then, to note that at one moment in their paper Wicker et al. themselves naively invoked Stanislasvki’s acting theories in ways that unexpectedly redounded on themselves. The issue came up when Wicker et al. were discussing another experiment on emotional empathy, one that appeared the same year as their own and that covered somewhat similar ground. In the experiment in question, Laurie Carr and her associates asked the experimental participants—ordinary persons, not actors—to pose all six of the “basic emotions,” including disgust, in order to determine by fMRI whether the same neural substrate was activated both when the participants actually experienced emotions through posing or imitation in this way, and when they observed the same emotions in others, by observing a set of Ekman and Friesen’s photographs of facial expressions on a computer screen.30 Carr’s research group showed that both the imitation of emotions and their observation activated a largely similar network of brain regions, including the anterior insula, although activation was greater when the subjects imitated the expressions than when they merely passively observed them in others.31
In their paper Wicker and his team acknowledged the agreement between their own results and those of other researchers, including those of Carr et al. But they also drew attention to certain differences. They pointed out that no previous study of disgust, including that of Carr and her colleagues, had actually evoked the “sensation of disgust” in experimental subjects, as they themselves had done, in order to investigate whether the activated locations were common to both the experience of disgust and the perception of the same emotions in others. They stressed in this regard that merely imitating or posing an emotion, as Carr’s experimental subjects were asked to do, does not require or guarantee that the poser subjectively feels the portrayed affect, because “imitation usually does not require experiencing the imitated emotion” (“BUD,” 658-59). They thus declared that Carr’s research group had demonstrated only that the insula was involved in imitation, not that it was directly involved in the “experience of emotions” (“BUD,” 659). In other words, Wicker’s team claimed that, unlike the subjects in their own experiment who, by smelling a foul odor actually experienced the emotion or sensation of disgust, the participants in Carr’s experiment might only have represented but not personally felt the emotions they were showing on their faces (as if Carr’s subjects only experienced “cold” emotional responses).
Since Carr and her group found that the insula was nevertheless activated, their findings appeared to invalidate the claim by Wicker and his colleagues that the insula is necessary for actual emotional experience. But Wicker et al. ingeniously proposed a solution to this apparent difficulty. They suggested that, like good method actors, some of Carr et al.’s participants must have been so swept up in their role that they really must have felt the emotions they were portraying on their faces. “However,” Wicker’s group observed in this connection, “in the light of our findings, it is possible that, during imitation, some of their participants felt the imitated emotion—as actors do when using the ‘Stanislavsky’ method of emotion induction” (“BUD,” 659).32 I call the invocation by Wicker and his team of Stanislavski’s theory of acting “naïve” because the authors don’t seem to have appreciated the problem of acting in their own case. The interesting question here is: Why in their own experiment did these investigators use not ordinary persons but precisely actors to perform expressions in front of the camera for the purposes of making portraits of disgusted, neutral, or pleased facial expressions to show to the participants in the experiment? If disgusting smells are disgusting to everyone and automatically induce the experience (or “sensation”) of disgust, then ordinary volunteers could have served the investigators’ purposes just as well. The fact that professional actors were used and that they were asked to display expressions in a “natural but clear way” (“BUD,” 661) suggests that some degree of acting skill and “stage direction” was necessary to produce the required disgust display, or at any rate that Wicker and his team believed that to be the case—in other words, they believed, or proceeded as if they believed, that ordinary people are not very good at portraying such emotional expressions in the way scientists require. We might put it that in their experiment, Wicker and his colleagues functioned in part as directors of the facial displays, although it remains an open question whether the performers slipped into their role so deeply that, like good “method” actors, they really felt the emotion or “sensation” of disgust the investigators attributed to them—as I say, the actors were not asked. In any case, the notion of a “natural but clear” display begs every conceivable question, implying as it does that performers or actors are capable on demand of producing “natural” appearances (as opposed to what exactly?) and moreover that they can on demand produce emotional expressions that are “intense but natural” and not, let us say, overdone or exaggerated.33 But the entire history of modern theories of dramaturgy testifies to the fact that nothing of the sort can be taken for granted.34 All this may be summed up by saying that in their appeal to the ideas of Stanislasvki, Wicker’s team inadvertently drew attention to the contextual-social influences at work in the production of emotional expressions, influences that their Ekman-inspired reflex, corporeal, readout approach to the affects was meant to forestall.
The disgust story does not end here. Perhaps aware that the 2003 experiment on disgust by Wicker and his group was defective in some respects, investigators returned to the fray with a follow-up experiment in 2007. In the new study, by Jabbi, Swart, and Keysers (the latter being one of the authors of the 2003 experiment), disgusting tastes rather than disgusting smells were the focus of inquiry, but the basic experimental set-up remained the same. As before, actors were filmed while posing disgusted, pleased, and neutral expressions in a “naturally vivid manner,” this time when sipping unpleasant (quinine), pleasant (sucrose) and neutral (artificial saliva) solutions from a cup, and the ten best clips for each emotional category were selected for use in the experiment. In the “Visual runs” the experimental participants (eighteen right-handed subjects, ten females and eight males) were asked to observe the movie clips of those posed expressions while they themselves underwent fMRI. In the “Gustatory runs” the participants were asked to sip the same liquids as those the actors had tasted, again while undergoing brain scanning. (The solutions were delivered by an experimenter standing beside the MRI scanner, using a tubing system consisting of a syringe connected to an infusion tube inserted into a pacifier.) Just as in the previous experiment, insula activation was reported in both the observing and the gustatory or “experiencing” condition. But this time the investigators added a new feature: they asked the participants to rate their own experiences both on tasting the solutions and on seeing the actors’ emotional expressions when the latter posed their facial reactions to the same drinks. It’s as if the researchers recognized that, without documenting the participants’ actual subjective states, the “hot” hypothesis predicting that the participants would actually experience the same emotion as those whom they were observing had remained unproven. Put less critically, it’s as if they wanted to document assumptions that in their 2003 paper Wicker et al. had apparently taken for granted but that skeptics could rightly question.35
It is worth remarking that the attempt to evaluate the participants’ subjective responses raised some theoretical difficulties for Jabbi et al. The hot hypothesis claimed that observers experience emotions in an automatic, non-cognitive way just by observing the facial expressions of others. That hypothesis cannot be supported without demonstrating that people really do experience disgust when they see disgust expressions in others—evidence of brain activation alone will not suffice. The dilemma Jabbi et al. faced was that the attempt to determine an observer’s emotional experience required asking him or her to make conscious and explicit what, on the hot hypothesis, had been theorized as an implicit, non-conscious and sub-personal process. Evaluating a participant’s subjective feelings therefore necessitated asking him or her to transform a hypothesized non-cognitive experience or event into an actual cognitive one in order to articulate and report on it. In effect the hypothesis of emotional simulation couldn’t be tested, because the moment the researchers asked their subjects to report on their subjective experience the latter were doing cognition and hence transforming what was understood to be a “hot,” non-cognitive process into a cognitive one. In short, the hot hypothesis couldn’t be confirmed without contradicting its basic, non-cognitive premise.
Moreover, in designing their experiment Jabbi and his colleagues appear to have been motivated by a further concern, namely, that although the hot hypothesis could explain the observer’s tendency to emotional “contagion” or emotional resonance, it couldn’t in itself account for the empathic “understanding” of another, as the hot hypothesis had seemed to propose. As Jabbi’s research team observed in this regard, infants contagiously cry when they witness the distress of other people but are presumably unable to distinguish their feelings from those of others. In contrast, more mature persons not only resonate contagiously to the emotions of others, but are able to interpret and attribute their subjective states to someone else while distinguishing their emotions from those of another, thereby acquiring genuine “empathic understanding” or “conscious knowledge” of the other. In short, in their paper Jabbi and his colleagues now appeared to concede that mirroring or resonance or contagion of the kind proposed by the hot hypothesis might be a prerequisite for empathic “understanding” of another but is not sufficient for it, as the hot hypothesis had at first appeared to claim.36
Against this background of issues and concerns, we can understand why in their 2007 experiment Jabbi and his team made an effort to determine the subjective responses of their experimental subjects.37 First, the researchers rated the subjective reactions to the gustatory emotions of the actors in the movies by asking the participants how willing they would be to drink the beverages the actors had just tried (using a scale from – 6 “absolutely not willing,” to 6 “very much willing”). Second, the investigators asked the participants to rate the solutions they themselves had to ingest during the experiment (on a scale ranging from “extremely disgusting” to “extremely delicious”). These scales were taken to be measures of the participants’ evaluations of the beverages involved, in the third person (“He tastes”) and the first person perspective (“I taste”), thus allowing a direct comparison of these two perspectives. In other words, how willing the participants were to taste the drinks they witnessed the actors ingesting was taken to be a measure of the affective states the facial expressions induced in them. In addition, Jabbi et al. obtained the participants’ self-reported empathy scores as measured by an Interpersonal Reactivity Index. The investigators then correlated these scores with the insula activation that occurred during the same participants’ witnessing the clips of the actors posing the pleased, or disgusted, or neutral expressions.38
The main new result reported by Jabbi et al. was that for the first time it had been demonstrated that during the observation of other people’s “gustatory emotions” (that is, the observation of other people’s disgust expressions), the size of insula activation correlated with differences in self-reported interpersonal reactivity, or empathy. They took this finding to extend the previous demonstration by Wicker et al. that the insula was activated during the experience and observation of negative emotional states, such as disgust, and therefore to provide further support for the hypothesis that the anterior insula was involved in the transformation of emotional states into experienced ones. Their results also showed that the insula’s involvement was not restricted to negative emotions but was involved in the processing of positive emotions as well.
In the light of the criticisms I have already offered in my paper, many questions could be raised about this experiment and its purported findings, but here I will raise only two.39 First, Jabbi et al. appear to have made no attempt to ascertain whether the participants (observers) felt disgust or pleasure when they actually watched the actors’ facial expressions, so that their effort to determine their experimental subjects’ subjective experience seems to have fallen short.40 Equally interesting from my point of view is the fact that Jabbi et al. made no attempt to discover what the actors experienced when they were asked to taste various liquids and produce the relevant facial movement or expression in order to be filmed. Why did the researchers limit their inquiries in this regard? Perhaps the investigators assumed that the liquids the actors were asked to sip inevitably aroused in them the relevant experience of disgust or pleasure and, according to the readout theory, therefore also produced the relevant facial expression.41 Or maybe the researchers took it for granted that facial mimicry of the kind involved in posing expressions automatically induces in actors the relevant internal emotional states (although the evidence on the topic of facial-mimicry or facial feedback is mixed at best).42 But Jabbi and his research group didn’t address this question at all.
Why does the omission matter? I think it matters because, by failing to determine the actors’ personal or subjective experiences, the authors left open the possibility that, just as in the earlier experiment by Wicker’s research team, so in this experiment the actors might not have actually experienced disgust themselves but merely posed the facial expressions they were asked to represent on their faces. (Of course, as I’ve said, the quinine used to induce the actors’ disgust expression was taken to be inherently disgusting, but this claim was not tested by asking the actors their subjective reactions, so it remains an open question whether such a response should have been taken for granted.) Actors do this all the time, and indeed Ekman’s neo-cultural theory predicts insincerity or feigning in many social situations, of which the demand that actors pose an expression can serve as an example. But the effect of the omission is to suggest that since, according to the “hot hypothesis” of emotional empathy, we automatically empathize with, or resonate to, the emotional expressions of others, we will do so whether or not the people we observe are really feeling what they show on their faces. The hot hypothesis therefore seems to imply that we are destined to spend our days resonating madly, nonselectively, immoderately, automatically to whatever facial signals someone else, anyone else, sends us, without our knowing whether those signals are telling us the truth about the latter’s emotional state. If the mirror neuron theory of simulation is true, we can be fooled—we will be fooled—about the emotional states of others all the time. Both of us disgusted in my insula? It might be more accurate to say that I will be disgusted in my insula as long as you display or perform an expression of disgust—regardless of whether you are sincere. But what kind of theory is that?
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It is often said by scientists that our understanding of the neural basis of empathy is in its infancy, the suggestion being that it is only a matter of time before problems will be solved, as if the difficulties facing the research field are merely technical. But the implication of my paper is that the issues confronting empathy theorists are as much theoretical or, say, philosophical, as they are technical or scientific. Adam Smith’s name is today routinely evoked in introductory remarks on the nature of empathy. But how many people realize that for Smith empathy (or sympathy) was not a natural phenomenon or an automatic process of resonance with the feelings of another? Rather, according to him sympathy was conditioned by an inherent theatricality that, by making persons into actors and spectators who distance themselves from each other and even from themselves, forestalls the possibility (the dream) of complete sympathetic merger or identification.43 Freud expressed the same difficulty, indeed impossibility, in his own way when he made psychical ambivalence—the constitutive impossibility of separating Eros and Thanatos, love and hate, immersion and distance—central to his understanding of the sympathetic-identificatory phenomenon. According to Freud, rivalry with the other is as inherent in human nature as is love, and indeed is inseparable from love: the taming of these emotions is the necessary but endless task of civilization.44 For such thinkers, then, our knowledge of other minds cannot be explained by an appeal to a simple mechanism of mutual resonance or mutual attunement of the sort I have analyzed here. A further implication of my paper is that the problem of emotional empathy can only be rendered the more intractable if investigators persist in adopting the theoretical assumptions and experimental methods associated with the Basic Emotions View and the mirror neuron hypothesis.