Is disgust sensitive to classical conditioning as indexed by facial electromyography and behavioural responses?

Earlier studies provided preliminary support for the role of classical conditioning as a pathway of disgust learning, yet this evidence has been limited to self-report. This study included facial electromyographical (EMG) measurements (corrugator and levator muscles) and a behavioural approach task to assess participants’ motivation-to-eat the actual food items (conditioned stimuli, CS). Food items served as CS and film excerpts of a woman vomiting served as unconditioned stimuli (US). Following acquisition the CS+ (neutral CS paired with US disgust) was rated as more disgusting and less positive. Notably, the conditioned response was transferred to the actual food items as evidenced by participants’ reported lowered willingness-to-eat. Participants also showed heightened EMG activity in response to the CS+ which seemed driven by the corrugator indexing a global negative affect. These findings suggest that classical conditioning as a pathway of disgust learning can be reliably observed in subjective but not in disgust-specific physiological responding.     

恐惧与厌恶情绪图片系统的编制：基于两种情绪的区分

基于恐惧与厌恶情绪刺激材料界定模糊的问题,实验一在总结前人研究中实验材料方面混淆恐惧和厌恶的基础上,通过问卷法完成了对恐惧与厌恶图片系统初步的搜集、整理工作;实验二通过进一步测评得到了具有良好信度的恐惧与厌恶情绪图片系统,图片系统中的恐惧与厌恶情绪很好的分离,且图片系统中动物、场景、物体三类图片的恐惧、厌恶程度均存在显著差异,可适用于需要不同种类情绪刺激的具体应用性研究。     

恐惧与厌恶情绪图片系统的编制：基于两种情绪的区分

基于恐惧与厌恶情绪刺激材料界定模糊的问题,实验一在总结前人研究中实验材料方面混淆恐惧和厌恶的基础上,通过问卷法完成了对恐惧与厌恶图片系统初步的搜集、整理工作;实验二通过进一步测评得到了具有良好信度的恐惧与厌恶情绪图片系统,图片系统中的恐惧与厌恶情绪很好的分离,且图片系统中动物、场景、物体三类图片的恐惧、厌恶程度均存在显著差异,可适用于需要不同种类情绪刺激的具体应用性研究。     

高低强迫清洗倾向个体对负性情绪注意偏向的差异

摘 要 本研究采用返回抑制范式,以诱发厌恶、恐惧和中性情绪的图片为线索,考察高、低强迫清洗倾向个体对负性情绪刺激注意偏向的差异及其发生机制。结果表明：（1）被试对诱发厌恶和恐惧的图片均产生了注意偏向且注意偏向是由注意解除困难所引起;（2）被试对诱发厌恶图片的注意偏向程度显著大于对诱发恐惧图片的注意偏向程度;（3）高、低强迫清洗倾向个体对诱发厌恶和恐惧图片的注意偏向程度之间的组间差异均不显著。     

Pavlovian Disgust Conditioning and Generalization: Specificity and Associations With Individual Differences

Although studies have identified differences between fear and disgust conditioning, much less is known about the generalization of conditioned disgust. This is an important gap in the literature given that overgeneralization of conditioned disgust to neutral stimuli may have clinical implications. To address this knowledge gap, female participants (n = 80) completed a Pavlovian conditioning procedure in which one neutral food item (conditioned stimulus; CS+) was followed by disgusting videos of individuals vomiting (unconditioned stimulus; US) and another neutral food item (CS–) was not reinforced with the disgusting video. Following this acquisition phase, there was an extinction phase in which both CSs were presented unreinforced. Importantly, participants also evaluated generalization stimuli (GS+, GS?) that resembled, but were distinct from, the CS after each conditioning phase. As predicted, the CS+ was rated as significantly more disgusting and fear inducing than the CS? after acquisition and this pattern persisted after extinction. However, disgust ratings of the CS+ after acquisition were significantly larger than fear ratings. Participants also rated the GS+ as significantly more disgusting, but not fear inducing, than the GS? after acquisition. However, this effect was not observed after extinction. Disgust proneness did predict a greater increase in disgust and fear ratings of the CS+ relative to the CS? after acquisition and extinction. In contrast, trait anxiety predicted only higher fear ratings to the CS+ relative to the CS? after acquisition and extinction. Disgust proneness nor trait anxiety predicted the greater increase in disgust to the GS+ relative to the GS? after acquisition. These findings suggest that while conditioned disgust can generalize, individual difference variables that predict generalization remain unclear. The implications of these findings for disorders of disgust are discussed.     

Emotional and neutral scenes in competition: Orienting,efficiency, and identification

To investigate preferential processing of emotional scenes competing for limited attentional resources with neutral scenes, prime pictures were presented briefly (450 ms), peripherally (5.2° away from fixation), and simultaneously (one emotional and one neutral scene) versus singly. Primes were followed by a mask and a probe for recognition. Hit rate was higher for emotional than for neutral scenes in the dual- but not in the single-prime condition, and A′ sensitivity decreased for neutral but not for emotional scenes in the dual-prime condition. This preferential processing involved both selective orienting and efficient encoding, as revealed, respectively, by a higher probability of first fixation on—and shorter saccade latencies to—emotional scenes and by shorter fixation time needed to accurately identify emotional scenes, in comparison with neutral scenes.     

Emotional and neutral scenes in competition: orienting, efficiency, and identification

To investigate preferential processing of emotional scenes competing for limited attentional resources with neutral scenes, prime pictures were presented briefly (450 ms), peripherally (5.2° away from fixation), and simultaneously (one emotional and one neutral scene) versus singly. Primes were followed by a mask and a probe for recognition. Hit rate was higher for emotional than for neutral scenes in the dual- but not in the single-prime condition, and A' sensitivity decreased for neutral but not for emotional scenes in the dual-prime condition. This preferential processing involved both selective orienting and efficient encoding, as revealed, respectively, by a higher probability of first fixation on—and shorter saccade latencies to—emotional scenes and by shorter fixation time needed to accurately identify emotional scenes, in comparison with neutral scenes.     

阈下启动的恐惧和厌恶情绪对人际判断的影响

该研究通过两个实验,采用单因素的组间设计,探讨了阈下启动的恐惧情绪和厌恶情绪对人际判断的影响作用。研究结果显示:1)阈下呈现恐惧图片的情况下,被试认为随后的中性人物面孔图片表现出更多的攻击性和威胁性,相对于阈下呈现中性图片的条件;2)阈下呈现厌恶图片的情况下,被试认为人物随后的中性人物面孔图片表现出更多的无礼性和令人讨厌,相对于阈下呈现中性图片的条件。研究结果表明,在具体情绪的水平上,阈下情绪启动会影响被试随后的人际判断。     

Depressive Symptomatology and College Persistence among African American College Students

ABSTRACT. While many studies find women self-report higher disgust sensitivity than men, few studies have examined gender differences with behavioral tasks in senses other than vision. On a haptic task, we tested the hypothesis that women would report greater disgust but not greater unpleasantness than men. Forty-four undergraduates (29 women) touched 8 out-of-sight stimuli with sensory (unpleasantness) and emotional (disgust) responses recorded. The stimuli consisted of 2 neutral, 2 pleasant, and 4 unpleasant (3 disgust-evoking) objects. No gender differences were found for reporting stimuli unpleasantness. In contrast, women rated their disgust significantly higher than men when touching the high disgust-evoking objects. Unpleasantness of the stimuli correlated with disgust to the objects, but disgust sensitivity (Disgust Scale-Revised) was not a strong predictor of disgust responses. Besides differentiating unpleasantness from disgust, this was also the first study to show gender differences in a disgust-evoking haptic task.     

Shaking That Icky Feeling: Effects of Extinction and Counterconditioning on Disgust-Related Evaluative Learning

Learned disgust appears to play an important role in certain anxiety disorders, and can be explained by the process of evaluative conditioning, in which an affective evaluative reaction evoked by an unconditional stimulus (US) is transferred to a conditional stimulus (CS). Much remains unknown about how disgust-related evaluative learning can be effectively eliminated. Study 1 of the present investigation examined the effects of extinction on reducing the negative evaluation of a CS that was acquired during disgust conditioning. Participants completed acquisition trials, with a disgusting picture as US and two neutral pictures as CS (CS + was paired with the US; CS- was unpaired), followed by extinction trials ("CS only"; experimental condition) or a filler task (control condition). Extinction trials reduced acquired US expectancy to the CS +, but did not extinguish negative evaluations of the CS +. Study 2 examined the effects of counterconditioning on evaluative learned disgust. After disgust acquisition trials, counterconditioning trials followed in which the CS + was paired with a pleasant US (experimental condition) or a filler task (control condition). Counterconditioning trials reduced acquired US expectancy to the CS + and reduced evaluative conditioned disgust. Implications of the potential differential effects of extinction and counterconditioning on evaluative learning for exposure-based treatment of specific anxiety disorders are discussed.     

The facial pattern of disgust, appetence, excited joy and relaxed joy: an improved facial EMG study

The purpose of the study was to investigate the facial muscle pattern of disgust in comparison to appetence and joy, using an improved facial EMG method. We analyzed the activity of nine facial muscles in forty healthy subjects. The subject group was randomly divided into two groups (oversaturated vs. hungry) of ten women and ten men each. Four different emotions (disgust, appetence, excited-joy and relaxed-joy) were induced by showing pictures from the IAPS. Pre-visible facial muscle activity was measured with a new facial EMG. A Visual Analog Scale (VAS) was established. Disgust is represented by a specific facial muscle pattern involving M.corrugator and M.orbicularis oculi, clearly distinguishing it from the facial patterns of appetence and joy. The intensity of disgust is stronger in a state of hunger than under oversaturation and is altogether stronger in females than in males. Our findings indicate the possibility to explore the entire emotion system successfully through a state-of-the-art psychophysiological method like our EMG device.     

Eye movement assessment of selective attentional capture by emotional pictures

The eye-tracking method was used to assess attentional orienting to and engagement on emotional visual scenes. In Experiment 1, unpleasant, neutral, or pleasant target pictures were presented simultaneously with neutral control pictures in peripheral vision under instruction to compare pleasantness of the pictures. The probability of first fixating an emotional picture, and the frequency of subsequent fixations, were greater than those for neutral pictures. In Experiment 2, participants were instructed to avoid looking at the emotional pictures, but these were still more likely to be fixated first and gazed longer during the first-pass viewing than neutral pictures. Low-level visual features cannot explain the results. It is concluded that overt visual attention is captured by both unpleasant and pleasant emotional content.     

Emotional responding to fearful and disgusting stimuli in specific phobics

Individuals with small animal and blood-injection-injury (BII) phobias respond to phobia-relevant stimuli with both fear and disgust. However, recent studies suggest that fear is the dominant emotional response in animal phobics whereas disgust is the primary emotional response in BII phobics. The present study examined emotional responding toward pictures of spiders, surgical procedures, and two categories of general disgust elicitors (rotting food and body products) among analogue spider phobics, BII phobics, and nonphobics. Dominant emotional responses to phobia-relevant stimuli clearly differentiated the groups. as spider phobics were more likely to be classified as primarily fearful when rating pictures of spiders (74%), whereas BII phobics were more likely to be classified as primarily disgusted when rating pictures of surgical procedures (78%). Discriminant function analyses revealed that disgust ratings, but not fear ratings, of the phobic pictures were significant predictors of phobic group membership. Both phobic groups were characterized by elevated disgust sensitivity toward video and pictorial general disgust elicitors. Implications and suggestions for continued research examining fearful and disgusting stimuli in specific phobia are outlined.     

厌恶与恐惧情绪习得的性别差异研究:一项ERP研究

采用事件相关电位技术（ERPs）,用条件性习得范式探讨厌恶与恐惧情绪习得的性别差异。行为结果表明,在成功习得厌恶、恐惧和中性情绪之后,男女性在唤醒度维度上,性别差异显著;脑电结果表明,在早期N1和P2成分,厌恶情绪与恐惧情绪的习得无显著性别差异;但男女不同性别在N2成分上差异显著,主要表现为女性在厌恶、恐惧、中性这三类CS的N2成分均差异显著,但男性仅厌恶与中性情绪的CS差异显著。结果表明在负性情绪的习得中,女性比男性更敏感。     

Perspective taking and emotion: The case of disgust and sadness

In a recent study (Gilead et al., 2016), perspective taking (PT) was found to have a significant effect on affect ratings of negative pictures compared to neutrals. The current study explores the question whether PT would be affected equally by distinct negative emotions. We used neutral pictures and pictures classified as provoking sadness or disgust, matched for their intensity and arousal. Participants were asked to rate the pictures (on a scale from 1—no emotional reaction, to 5—very strong reaction) from 3 different perspectives - tough, sensitive, or their own – “me”. In Experiment 1, all pictures were mixed in the same blocks. In Experiment 2, the sad and disgust pictures were separated into two different blocks (each including neutrals). Both experiments showed significant interaction between PT and emotion. PT was found to be influenced by valence; however, distinct negative emotions were found to affect PT similarly.     

The psychopath as observer: emotion and attention in picture processing

This study extended prior work showing abnormal affect-startle modulation in psychopaths. Male prisoners viewed specific categories of pleasant (erotic or thrilling) and unpleasant (victim or direct threat) slide pictures, along with neutral pictures. Acoustic startle probes were presented early (300 and 800 ms) and late (1,800, 3,000, and 4,500 ms) in the viewing interval. At later times, nonpsychopaths showed moderate and strong reflex potentiation for victim and threat scenes, respectively. For psychopaths, startle was inhibited during victim scenes and only weakly potentiated during threat. Psychopaths also showed more reliable blink inhibition across pleasant contents than nonpsychopaths and greater heart rate orienting to affective pictures overall. These results indicate a heightened aversion threshold in psychopaths. In addition, deficient reflex modulation at early times suggested a weakness in initial stimulus evaluation among psychopaths.     

Linking Pavlovian Disgust Conditioning and Eating Disorder Symptoms: An Analogue Study

Although the experience of disgust is commonly endorsed among women with eating disorders, it remains unclear how to best model this emotion in relation to disordered eating. The present study sought to identify potential disgust conditioning abnormalities that may underlie the development of eating disorder symptoms. Individuals high and low in eating disorder symptoms (HED, n = 19; LED, n = 18) completed a Pavlovian conditioning procedure in which one neutral food item (conditioned stimulus; CS +) was followed by disgusting videos of individuals vomiting (unconditioned stimulus; US) and another neutral food item (CS–) was not reinforced with the disgusting video. Following this acquisition procedure, there was an extinction procedure in which both CSs were presented unreinforced. The results showed that ratings of disgust, fear, and willingness to eat the CS + and CS- did not significantly vary as a function of the conditioning phase for the LED group. However, the HED group rated the CS + as significantly more disgusting and fear inducing than the CS- after the acquisition phase and this pattern persisted after extinction. These conditioning effects were also observed to be significantly larger for disgust compared to fear. The HED group also reported being significantly less willing to eat the CS + compared to the CS- after the acquisition phase and this pattern also persisted after extinction. In the full sample, only discriminant disgust responding after acquisition was associated with the amount of calorie consumption over the 24-hour period after conditioning. These findings suggest that eating disorder symptoms may result from a heightened proneness to associate disgusting outcomes with otherwise neutral food items. This pattern of disgust learning may reinforce food avoidance in eating disorders and appears to be difficult to fully unlearn.     

Differential response patterns to disgust-related pictures

ABSTRACT

In the present study, attentional bias was investigated as a potential predisposing mechanism for the contamination-related subtype of obsessive-compulsive disorder (C-OC disorder). Fifty healthy participants with varying degrees of subclinical C-OC symptoms performed a visual search task to measure differential attentional biases elicited by neutral, disgust-, and fear-specific pictorial material. Participants had to find a target picture within five neutral distractor pictures randomly presented on different locations in an array. The task was to decide whether the array contained an unpleasant target picture or not. In randomly-selected emotional trials, participants were further asked about the content of the picture and the confidence of their answer. The results show that the reaction times significantly differed between the emotional and neutral pictures. Participants were significantly more confident in answering questions referring to fear compared to disgust pictures. This effect was marginally amplified in participants with higher C-OC symptoms. We discuss the results within the framework of the cost and benefit hypothesis, which postulates that disgust evolutionarily elicits stronger uncertainty compared to fear, owing to the ambiguous nature of the stimuli. Increased uncertainty might be an important but underestimated factor for pathological disgust experience, such as in obsessive-compulsive disorder.     

Human evaluative conditioning: Order of stimulus presentation

In an experiment designed to demonstrate evaluative conditioning, subjects were shown 48 pictures of sculptures that they rated on a scale with 21 categories (?10 to +10). Then, the two most liked pictures (L) were paired with pictures from the categories ?1, 0, or +1 (N). In contrast to prior experiments, subjects were given either forward conditioning (N-L) or backward conditioning (L-N) trials but not both. Four other neutral stimuli were paired with each other (N-N) and acted as control stimulus pairs. After conditioning, the stimuli were rated a second time. There was a statistically significant difference in evaluative ratings showing a change of the evaluative tone of the previously neutral stimuli in a positive direction only after forward conditioning. This finding is inconsistent with results of prior experiments and challenges the assumption of Martin and Levey (1987) that evaluative conditioning is different from human classical conditioning.     

Disgust sensitivity and fear of animals: Effect of exposure to violent or revulsive material

Subjects were asked to rate their fear of four categories of animals both before and after viewing one of three brief video films. Subjects watched either (a) a video depicting extreme violence, (b) a video depicting revulsive scenes from a hospital operation, or (c) a video showing neutral landscape scenes. The results suggested that exposure to violent material produced an increase in fear ratings for animals in the Hi Fear/Hi Predatory category (e.g., lion, tiger, shark) which was significantly different from a decrease in fear ratings recorded for all other categories of animals. However, exposure to revulsive material produced an increase in fear ratings to animals in both the Hi Fear/Lo Predatory category (e.g., rat, spider, snake) and the Hi Revulsion category (e.g., slug, maggot, snail) which was significantly different to the decrease in fear ratings recorded for animals in the remaining categories. The neutral landscape scenes produced a decrease in mean fear ratings for all categories of animals. These results are considered further support for a disease-avoidance model of common animal fears, and suggest a causal link between disgust sensitivity and fear of certain fear-relevant animals.