Aiming for the stomach and hitting the heart: dissociable triggers and sources for disgust reactions.

Disgust reactions can be elicited using stimuli that engender orogastric rejection (e.g., pus and vomit; core disgust stimuli) but also using images of bloody injuries or medical procedures (e.g., surgeries; blood [body] boundary violation [B-BV] disgust stimuli). These two types of disgust reaction are presumed to be connected by a common evolutionary function of avoiding either food- or blood-borne contaminants. However, reactions to bloody injuries are typically conflated with reactions to the potential pain being experienced by the victim. This may explain why the two forms of "disgust", although similarly communicated (through self-report and facial expressions), evince different patterns of physiological reactivity. Therefore, we tested whether the communicative similarities and physiological dissimilarities would hold when markers of potential contamination in the latter category are removed, leaving only painful injuries that lack blood or explicit body-envelope violations. Participants viewed films that depicted imagery associated with (a) core disgust, (b) painful injuries, or (c) neutral scenes while we measured facial, cardiovascular, and gastric reactivity. Whereas communicative measures (self-report and facial muscles) suggested that participants experienced increased disgust for core disgust and painful injuries, peripheral physiology dissociated the two: core disgust decreased normal gastric activity and painful-injury disgust decelerated heart rate and increased heart rate variability. These findings suggest that expressions of disgust toward bodily injuries may reflect a fundamentally different affective response than those evoked by core disgust and that this (cardiovascularly mediated) response may in fact be more closely tied to pain perceptions (or empathy) rather than contaminant-laden stimuli

Disgust as embodied moral judgment.

How, and for whom, does disgust influence moral judgment? In four experiments participants made moral judgments while experiencing extraneous feelings of disgust. Disgust was induced in Experiment 1 by exposure to a bad smell, in Experiment 2 by working in a disgusting room, in Experiment 3 by recalling a physically disgusting experience, and in Experiment 4 through a video induction. In each case, the results showed that disgust can increase the severity of moral judgments relative to controls. Experiment 4 found that disgust had a different effect on moral judgment than did sadness. In addition, Experiments 2-4 showed that the role of disgust in severity of moral judgments depends on participants' sensitivity to their own bodily sensations. Taken together, these data indicate the importance-and specificity-of gut feelings in moral judgments

Neural responses to facial and vocal expressions of fear and disgust

Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus

Deontological morality can be experimentally enhanced by increasing disgust. A transcranial direct current stimulation study

Previous studies empirically support the existence of a distinctive association between deontological (but not altruistic) guilt and both disgust and obsessive-compulsive (OC) symptoms. Given that the neural substrate underlying deontological guilt comprises brain regions strictly implicated in the emotion of disgust (i.e. the insula), the present study aimed to test the hypothesis that indirect stimulation of the insula via transcranial direct current stimulation (tDCS) would enhance disgust and morality in the deontological domain. A randomized, sham-controlled, within-subject design was used. Thirty-seven healthy individuals (25 women) underwent 15-min anodal and sham tDCS over T3 in two different days, while their heart rate (HR) was recorded to derive measures of parasympathetic nervous system activity (HR variability; HRV). After the first 10-min of sham or active tDCS stimulation, participants were asked to 1) complete a series of 6-item words that could be completed with either a disgust-related word (cleaning/dirtiness) or neutral alternatives; 2) rate how much a series of vignettes, each depicting a behavior that violated a specific moral foundation, were morally wrong. Levels of trait anxiety, depression, disgust sensitivity, scrupulosity, and altruism as well as pre- and post- stimulation momentary emotional states were assessed. Compared to the sham condition, after active stimulation of T3 a) HRV significantly increased and participants b) completed more words in terms of cleaning/dirtiness and c) reported greater subjective levels of disgust, all suggesting the elicitation of the emotion of disgust. Although the results are only marginally significant, they point to the absence of difference between the two experimental conditions for moral vignettes in the altruistic domain (i.e., animal care, emotional and physical human care), but not in the deontological domain (i.e., authority, fairness, liberty, and sacrality), where vignettes were judged as more morally wrong in the active compared to the sham condition. Moreover, scores on the OCI-R correlated with how much vignettes were evaluated as morally wrong in the deontological domain only. Results preliminarily support the association between disgust and morality in the deontological domain, with important implications for OC disorder (OCD). Future studies should explore the possibility of decreasing both disgust and morality in patients with OCD by the use of non-invasive brain stimulation techniques

Disgust Promotes Disposal: Souring the Status Quo

Humans naturally dispose of objects that disgust them. Is this phenomenon so deeply embedded that even incidental disgust--i.e., where the source of disgust is unrelated to a possessed object--triggers disposal? Two experiments were designed to answer this question. Two film clips served as disgust and neutral primes; the objects were routine commodities (boxes of office supplies). Results revealed that the incidental disgust condition powerfully increased the frequency with which decision makers traded away a commodity they owned for a new commodity (more than doubling the probability in each condition), thereby countering otherwise robust status quo bias (Samuelson & Zeckhauser, 1988). Decision makers were unaware of disgust's impact. Even when warned to correct for it, they failed to do so. These studies presented real choices with tangible rewards. Their findings thus have implications not only for theories of affect and choice, but also for practical improvements in everyday decisions.

Transgressions and expressions: Affective facial muscle activity predicts moral judgments

Recent investigations into morality suggest that affective responses may precede moral judgments. The present study investigated, first, whether individuals show specific facial affect in response to moral behaviors and, second, whether the intensity of facial affect predicts subsequent moral judgments. Muscle activity relating to disgust (levator labii), anger (corrugator supercilii), and positive affect (zygomaticus major) was recorded while participants considered third-person statements describing good and bad behaviors across five foundations of morality (purity, fairness, harm, authority, and ingroup). Facial disgust was highest in response to purity violations, followed by fairness violations. In contrast, harm violations evoked anger expressions. Importantly, the extremity of subsequent moral judgments was predicted by facial affect, such that judgments about purity and fairness correlated with facial disgust, harm correlated with facial anger, and ingroup correlated with positive facial affect. These results demonstrate that individuals spontaneously exhibit domain-specific moral affect that allows inferences about their moral judgments. </jats:p

Moral anger, but not moral disgust, responds to intentionality

We propose that, when people judge moral situations, anger responds to the contextual cues of harm and intentionality. On the other hand, disgust responds uniquely to whether or not a bodily norm violation has occurred; its apparent response to harm and intent is entirely explained by the co-activation of anger. We manipulated intent, harm, and bodily norm violation (eating human flesh) within a vignette describing a scientific experiment. Participants then rated their anger, disgust, and moral judgment, as well as various appraisals. Anger responded independently of disgust to harm and intentionality, while disgust responded independently of anger only to whether or not the act violated the bodily norm of cannibalism. Theoretically relevant appraisals accounted for the effects of harm and intent on anger; however, appraisals of abnormality did not fully account for the effects of the manipulations on disgust. Our results show that anger and disgust are separately elicited by different cues in a moral situation

The mediating roles of disgust sensitivity and danger expectancy in relation to hand washing behaviour

Copyright © 2010 British Association for Behavioural and Cognitive PsychotherapiesBackground: Recent interest in the role of vulnerability factors in obsessional washing has suggested that disgust sensitivity, danger expectancy and health anxiety may be of interest. Aims: This study explores the differential impact of these factors on both behavioural and cognitive measures of washing behaviour and is based on a replication of the Jones and Menzies (1997) experiment, during which participants immersed their hands in a noxious compound while rating themselves on a range of measures: the time they subsequently took to wash their hands was measured and danger expectancies were found to be the best predictor of this. Method: The present study added measures of disgust sensitivity and health anxiety to this experimental methodology while removing factors they found to be of little import to compulsive washing. Thirty non-clinical participants took part. Results: Results confirmed that disgust sensitivity was related to the behavioural measure of washing time, but that this relationship was almost entirely mediated by the danger expectancy concerning judgements of severity of consequent disease. However, a different pattern emerged when the outcome measure was questionnaire based: danger expectancy was not at all related to this. Disgust sensitivity mediated the relationship between health anxiety and scores on a questionnaire measure of washing compulsions. Interestingly, these scores were not related to the behavioural measure of washing time. Conclusions: The implications of these relationships to the further development of subtypes of Obsessive Compulsive Disorder (OCD) are discussed

Repugnance as Performance Error: The Role of Disgust in Bioethical Intuitions

An influential argument in bioethics involves appeal to disgust, calling on us to take it seriously as a moral guide (e.g. Kass, Miller, Kahan). Some argue, for example, that genetic enhancement, especially via human reproductive cloning, is repellant or grotesque. While objectors have argued that repugnance is morally irrelevant (e.g. Nussbaum, Kelly), I argue that the problem is more fundamental: it is psychologically irrelevant. Examining recent empirical data suggests that disgust’s influence on moral judgment may be like fatigue: an exogenous influence, yielding a “performance error” that does not reflect our understanding of moral matters. This conclusion also challenges appeals to repugnance on other topics (such as homosexuality) and generally downplays the importance of disgust in moral discourse

The effect of disgust-related side-effects on symptoms of depression and anxiety in people treated for cancer: a moderated mediation model

As maladaptive disgust responses are linked to mental health problems, and cancer patients may experience heightened disgust as a result of treatments they receive, we explored the associations between disgust-related side-effects and symptoms of depression and anxiety in people treated for cancer. One hundred and thirty two (83 women, Mage = 57.48 years) participants answered questions about their treatments, side-effects, disgust responding, and mental health. Experiencing bowel and/or bladder problems, sickness and/or nausea (referred to here as “core” disgust-related side-effects) was significantly related to greater symptoms of depression and borderline increased anxiety. Further, these links were explained by a moderated mediation model, whereby the effects of core disgust side-effects on depression and anxiety were mediated by (physical and behavioural) self-directed disgust, and disgust propensity moderated the effect of core disgust side-effects on self-disgust. These findings stress the importance of emotional responses, like disgust, in psychological adaptation to the side-effects of cancer treatments