Effects of experienced disgust on habituation during repeated exposure to threat-relevant stimuli in blood-injection-injury phobia

Despite growing evidence implicating disgust in the etiology of blood-injection-injury (BII) phobia, the relevance of disgust for exposure-based treatment of BII phobia remains largely unknown. Individuals with BII phobia were randomly assigned to a disgust (view vomit videos) or neutral activation (view waterfall videos) condition. They were then exposed to 14 videotaped blood draws, during which fear and disgust levels were repeatedly assessed. Participants then engaged in a behavioral avoidance test (BAT) consisting of exposure to threat-relevant stimuli. Examination of outcome comparing the identical first and last blood-draw clips revealed that fear and disgust toward blood draws was significantly reduced in both groups. Disgust levels were also found to be more intense for the video stimuli relative to fear levels whereas the opposite was true for BAT stimuli. Contrary to predictions, the disgust induction did not enhance reductions in negative responses to the target video or reduce behavioral avoidance. Growth curve analyses did show that individuals with BII phobia exposed to the disgust induction showed greater initial fear levels during repeated exposure than those in the neutral condition. However, this effect was not consistently observed across different analytic approaches. Changes in fear during exposure were also found to be independent of changes in disgust but not vice versa, and greater initial fear levels during repeated exposure to threat was associated with fear and disgust levels during the BAT. The implications of these findings for conceptualizing the role of disgust in etiology and treatment of BII phobia are discussed.     

An examination of the decline in fear and disgust during exposure-based treatment

It has been suggested that disgust plays a prominent role in the fear of spiders. Participants (N=27) displaying marked spider fear were provided 30 min of self-directed in vivo exposure to an actual tarantula, during which time their fear and disgust levels were assessed repeatedly. Growth curve analyses were then conducted to examine the decay slopes in both fear and disgust and their relationship. Consistent with prediction, exposure led to significant declines in both spider fear and spider-specific disgust but not in global disgust sensitivity. However, the decay slope observed for fear was significantly greater than that for disgust. Further analyses revealed that the reduction in disgust during treatment remained significant even after controlling for change in fear; and similarly, change in fear remained significant even after controlling for change in disgust. Contrary to prediction, disgust levels at pretreatment did not moderate the level of fear activation or fear reduction during treatment. Theoretical and clinical implications of the findings are discussed.     

A comparison of repeated exposure to fearful and disgusting stimuli among spider phobics

This study examined the role of fear and disgust in repeated exposure among spider phobics. Thirty spider phobics were randomly assigned to one of two experimental groups. Both groups completed measures of fear and disgust and performed two initial standardized Behavioral Avoidance Tests (BATs; one with a fear stimulus – live tarantula, and one with a disgust stimulus – dead rat). One group was then repeatedly exposed to the tarantula and the other to the dead rat. Results of the study indicated that exposure to either the disgust stimulus or the live tarantula was associated with significant decreases in fear, avoidance, and disgust. However, it was found that repeated exposure to the fear stimulus produced a greater decrease in avoidance behavior. Results suggest that both types of exposure can be effective in alleviating associated symptoms and provide additional evidence that disgust sensitivity plays a role in the treatment of spider phobia. Copyright © 2010 John Wiley & Sons, Ltd.     

The Effect of d-Cycloserine on Subliminal Cue Exposure in Spider Fearful Individuals

Research on d-cycloserine (DCS) has demonstrated a significant effect on symptom reduction in human studies that utilized conventional exposure-based approaches. Recent studies have offered promising results for targeting fears through subliminal paradigms. In this double-blind, randomized placebo-controlled study, 45 spider fearful individuals received DCS or placebo pills prior to completing a subliminal cue exposure task to images of spiders. Participants completed self-report questionnaires and a behavioral approach task to a live caged tarantula. After repeated exposure to subliminal spider cues, participants in the DCS group reported a greater reduction in disgust than individuals in the placebo group. No difference was observed in fear ratings. These findings suggest that DCS augments the reduction in disgust in spider fearful subjects after subliminal exposure to spider cues.     

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.     

I am going to gag: Disgust cognitions in spider and blood-injury-injection fears

There is mounting evidence that disgust plays an important role in certain anxiety disorders, yet little is known about disgust's cognitive component. The current study introduces a measure of cognitions associated with disgust and contamination to assess the role of disgust-specific primary and secondary appraisals in phobic responding. A multi-modal assessment of blood-injury-injection (BII) and spider phobia was conducted using BII (N=29) and spider (N=30) fearful groups, and a non-fearful control group (N=30). The Disgust Cognitions scale showed good reliability and validity, and distinguished among the groups. For example, relative to the other groups, the spider fear group reported higher disgust cognitions following presentation of a live spider, whereas the BII Fear group reported higher disgust cognitions following a surgery video. Moreover, the scale was associated with multiple phobic indicators (behavioral avoidance, subjective distress, symptom endorsement), suggesting cognitions may be critical to understanding how disgust contributes to anxiety disorders.     

Emotion-specific modulation of early visual perception

Exposure to fearful facial expressions enhances vision at low spatial-frequencies and impairs vision at high spatial-frequencies. This perceptual trade-off is thought to be a consequence of a fear-related activation of the magnocellular visual pathway to the amygdala. In this study we examined the generality of the effect of emotion on low-level visual perception by assessing participants' orientation sensitivity to low and high spatial-frequency targets following exposure to disgust, fear, and neutral facial expressions. The results revealed that exposure to fear and disgust expressions have opposing effects on early vision: fearful expressions enhanced low spatial-frequency vision and impaired high spatial-frequency vision, while disgust expressions, like neutral expressions, impaired low spatial-frequency vision and enhanced high spatial-frequency vision. Thus we show the effect of exposure to fear on visual perception is not a general emotional effect, but rather one that may that depend on amygdala activation, or one that may be specific to fear.     

I am going to gag: Disgust cognitions in spider and blood–injury–injection fears

There is mounting evidence that disgust plays an important role in certain anxiety disorders, yet little is known about disgust's cognitive component. The current study introduces a measure of cognitions associated with disgust and contamination to assess the role of disgust-specific primary and secondary appraisals in phobic responding. A multi-modal assessment of blood–injury–injection (BII) and spider phobia was conducted using BII (N=29) and spider (N=30) fearful groups, and a non-fearful control group (N=30). The Disgust Cognitions scale showed good reliability and validity, and distinguished among the groups. For example, relative to the other groups, the spider fear group reported higher disgust cognitions following presentation of a live spider, whereas the BII Fear group reported higher disgust cognitions following a surgery video. Moreover, the scale was associated with multiple phobic indicators (behavioural avoidance, subjective distress, symptom endorsement), suggesting cognitions may be critical to understanding how disgust contributes to anxiety disorders.     

Counterconditioning in the treatment of spider phobia: effects on disgust, fear and valence

From the perspective that disgust is a core feature of spider phobia, we investigated whether the treatment efficacy could be improved by adding a counterconditioning procedure. Women with a clinically diagnosed spider phobia (N = 34) were randomly assigned to the regular one-session exposure condition (EXP) or to the exposure with counterconditioning condition (CC). In the CC-condition tasty food-items were used during the regular exposure exercises and the participants' favourite music was played. Both treatment conditions appeared very effective in reducing avoidance behaviour and self-reported fear of spiders, strongly attenuated the disgusting properties of spiders and altered the affective evaluations in a positive direction. CC was not more effective in altering the affective valence of spiders than EXP and was not superior with respect to the long term treatment efficacy at 1 year follow up. Apparently, regular exposure treatment is already quite effective in altering the affective-evaluative component of spider phobia and it remains to be seen whether it is possible to further improve treatment outcome by means of procedures which are specifically designed to reduce the spiders' negative affective valence.     

To look or not to look: an eye movement study of hypervigilance during change detection in high and low spider fearful students

Previous eye movement studies of attentional bias in spider fear reported inconsistent results with respect to early attentional capture, suggesting that overt attentional capture only reliably occurs under specific circumstances. In addition, none of these studies explored covert attention. The present study examined attentional bias in spider phobia using a change detection paradigm that was expected to provide good conditions for documenting attentional capture. In contrast to our expectations, eye movement data showed that all participants' first fixations were fastest on general negative targets, whereas participants' first fixations on spider targets were slower in the spider fearful than in the nonfearful group. In addition, spider fearful participants made more nontarget fixations before fixating on a spider target than did nonfearful participants. Thus, we found that participants' overt attention was more quickly focused on general negative targets, whereas covert attentional processes enabled initial avoidance of fear-relevant (i.e. spider) stimuli. The present findings have important implications for research on attention and fear as they indicate that fearful individuals are not characterized by static attentional orienting toward threat but, under certain conditions, may avert attention from threat automatically.     

Some animal specific fears are more specific than others: Evidence from attention and emotion measures

Using a visual search methodology we investigated the effect of feared animal stimuli on attention. Our results confirmed the important role of emotion on attention. All participants detected fear-relevant stimuli (snakes and spiders) faster than neutral (mushrooms) ones against a background of fruits. In addition, spider fearful participants were sensitized specifically to detect their feared stimulus (spiders), compared to their fear-relevant but non-feared (snakes) and neutral stimuli. However, for participants fearful of snakes there was no significant difference in detection latencies between the feared (snakes) and the fear-relevant but non-feared animal stimuli (spiders). The results from the attention task were mirrored in the emotional ratings, which showed that spider fear was highly specific, whereas snake fear was associated with a more generalized enhanced evaluation of all negative stimuli.     

Disgust sensitivity and contamination fears in spider and blood-injection-injury phobias

Disgust has been implicated in the onset and maintenance of blood-injection-injury (BII) and animal phobias. Research suggests that people with these phobias are characterized by an elevated sensitivity to disgust-evoking stimuli separate from their phobic concerns. The disgust response has been described as the rejection of potential contaminants. Disgust-motivated avoidance of phobic stimuli may therefore be related to fears of contamination or infection. The present study compared BII phobics, spider phobics and nonphobics on two measures of disgust sensitivity and two measures of contamination fears. Positive correlations were found between disgust sensitivity and contamination fear. Specific phobics scored higher than nonphobics on all scales and BII phobics scored higher than spider phobics on contamination fear measures. Furthermore, the contamination fear scales were correlated with the blood phobia measure, but not correlated with the spider phobia measure. The results suggest that while both phobias are characterized by elevated disgust sensitivity, contamination fear is more prominent in BII than spider phobia.     

Behavioral avoidance tests and disgust in contamination fears: distinctions from trait anxiety

Much of the existing literature examining the role of disgust is limited to specific phobia. Recent research has begun to examine the role of disgust in contamination fear, a subtype of obsessive-compulsive symptoms. Through the use of behavioral avoidance tasks (BATs), the current study was designed to examine the role of disgust in people with contamination fears, with attention to distinguishing high and low trait anxiety. From a large screening of undergraduate students, three groups were formed based on their level of contamination fear and level of trait anxiety: contamination fearful ( n = 12 ), high-trait anxiety ( n = 11 ), and low trait anxiety ( n = 15 ). Subjects were asked to engage in six different BATs corresponding to six domains of disgust (food, animals, body products, body envelope violations, death, and sympathetic magic). One-way analysis of variance (ANOVA) showed significant differences between the contamination fearful group and the high trait anxiety group on the animal and sympathetic magic BATs. Significant differences on the food, animal, body envelope violations, and death BATs were also found between the contamination fearful group and the low-trait anxious group. The findings modestly support the importance of disgust in contamination fears. Implications for the study of disgust in contamination fear are provided.     

The role of fear and expectancies in capture of covert attention by spiders

Fear-related stimuli are often prioritized during visual selection but it remains unclear whether capture by salient objects is more likely to occur when individuals fear those objects. In this study, participants with high and low fear of spiders searched for a circle while on some trials a completely irrelevant fear-related (spider) or neutral distractor (butterfly/leaf) was presented simultaneously in the display. Our results show that when you fear spiders and you are not sure whether a spider is going to be present, then any salient distractor (i.e., a butterfly) grabs your attention, suggesting that mere expectation of a spider triggered compulsory monitoring of all irrelevant stimuli. However, neutral stimuli did not grab attention when high spider fearful people knew that a spider could not be present during a block of trials, treating the neutral stimuli just as the low spider fearful people do. Our results show that people that fear spiders inspect potential spider-containing locations in a compulsory fashion even though directing attention to this location is completely irrelevant for the task. Reduction of capture can only be accomplished when people that fear spiders do not expect a spider to be present.     

What is so frightening about spiders? Self‐rated and self‐disclosed impact of different characteristics and associations with phobia symptoms

Spider phobia is a common and impairing mental disorder, yet little is known about what characteristics of spiders that spider phobic individuals find frightening. Using screening data from a clinical trial, we explored which characteristics that spider‐fearful individuals (n = 194) rated as having the greatest impact on fear, used factor analysis to group specific characteristics, and explored linear associations with self‐reported phobia symptoms. Second, a guided text‐mining approach was used to extract the most common words in free‐text responses to the question: “What is it about spiders that you find frightening?” Both analysis types suggested that movement‐related characteristics of spiders were the most important, followed by appearance characteristics. There were, however, no linear associations with degree of phobia symptoms. Our findings reveal the importance of targeting movement‐related fears in in‐vivo exposure therapy for spider phobia and using realistically animated spider stimuli in computer‐based experimental paradigms and clinical interventions such as Virtual Reality exposure therapy.     

Contamination vs. harm-relevant outcome expectancies and covariation bias in spider phobia

There is increasing evidence that spiders are not feared because of harmful outcome expectancies but because of disgust and contamination-relevant outcome expectancies. This study investigated the relative strength of contamination- and harm-relevant UCS expectancies and covariation bias in spider phobia. High (n=25) and low (n=24) spider fearful individuals saw a series of slides comprising spiders, pitbulls, maggots, and rabbits. Slides were randomly paired with either a harm-relevant outcome (electrical shock), a contamination-related outcome (drinking of a distasting fluid), or nothing. Spider fearful individuals displayed a contamination-relevant UCS expectancy bias associated with spiders, whereas controls displayed a harm-relevant expectancy bias. There was no evidence for a (differential) postexperimental covariation bias; thus the biased expectancies were not robust against refutation. The present findings add to the evidence that contamination ideation is critically involved in spider phobia.     

Dissociable effects of fear and disgust in proactive and reactive inhibition

Numerous studies have demonstrated that negative emotional distracters impair inhibitory control. Nevertheless, two issues have emerged in prior studies. First, fear and disgust were inappropriately treated as a single category, which is particularly concerning given that they have been recently demonstrated to exert different impacts on inhibitory control. Second, inhibitory control might not be a unitary construct, as it can be further divided into proactive and reactive inhibition. Therefore, the present study aimed to investigate whether fearful and disgusting distracters have differential effects on proactive and reactive inhibition. Twenty-four female participants were instructed to perform a modified stop-signal task superimposed on a fearful, disgusting, or neutral image cue. Results showed that fearful distracters improved reactive inhibition when compared to disgusting and neutral distracters, while disgusting distracters enhanced proactive inhibition when compared to fearful distracters. Further, reactive and proactive inhibition was positively correlated under fearful, disgusting, and neutral contexts. This study is the first to provide evidence that fear and disgust may affect proactive and reactive inhibition differently. These results add to a growing literature linking emotion and inhibitory control, and they expand our understanding of the relationship between emotion and inhibition.     

A randomized, controlled clinical trial of in virtuo and in vivo exposure for spider phobia

The present study compared the efficacy of virtual reality (VR) in virtuo exposure and in vivo exposure in the treatment of spider phobia. Two treatment conditions were compared to a waiting-list condition. A 3-month follow-up evaluation was conducted in order to assess the durability of the treatment effects. Participants were randomly assigned to the treatment groups. A total of 16 participants received the in virtuo treatment, and 16 received the in vivo treatment. The waiting-list condition included 11 participants. Participants received eight 1.5-hour treatment sessions. Efficacy was measured with the Fear of Spiders Questionnaire, the Spider Beliefs Questionnaire (SBQ-F), and a Behavioral Avoidance Test (BAT). In addition, a clinician administered the Structured Interview for DSM-IV to assess DSM-IV's criteria for specific phobia and severity. Clinical and statistically significant improvements were found for both groups. Differences in treatment groups were found on one of five measures of fear: greater improvement on the SBQ-F beliefs subscale was associated with in vivo exposure.     

Erratum

Abstract

Recent research has highlighted the central role of disgust in the etiology and maintenance of contamination aversion (CA). Data would also suggest that, although amendable to the treatment of choice for CA (exposure and response prevention [ERP]), disgust is resistant to habituation. However, with regard to CA, it is not yet known if disgust's resistance to habituation is an artifact of the emotion or the disorder. Specifically, research has not yet indicated if severity of CA moderates the effect of ERP on disgust. Utilizing an undergraduate convenience sample (n=33), the present study compared emotional responding (disgust and fear) with repeated exposure to a disgusting contamination-relevant stimulus between participants who are high in contamination aversion (HCA; n=17) and low in contamination aversion (LCA; n=16). Results indicated that, habituation of disgust was slower than fear within the HCA group but not the LCA group. Contrasts revealed that the decay of fear across trials was faster for HCA participants when compared with LCA participants, although decay of disgust was similar between groups. These results indicate that habituation of disgust is slower than fear when elevated CA is present.     

The Set of Fear Inducing Pictures (SFIP): Development and validation in fearful and nonfearful individuals

Emotionally charged pictorial materials are frequently used in phobia research, but no existing standardized picture database is dedicated to the study of different phobias. The present work describes the results of two independent studies through which we sought to develop and validate this type of database—a Set of Fear Inducing Pictures (SFIP). In Study 1, 270 fear-relevant and 130 neutral stimuli were rated for fear, arousal, and valence by four groups of participants; small-animal (N = 34), blood/injection (N = 26), social-fearful (N = 35), and nonfearful participants (N = 22). The results from Study 1 were employed to develop the final version of the SFIP, which includes fear-relevant images of social exposure (N = 40), blood/injection (N = 80), spiders/bugs (N = 80), and angry faces (N = 30), as well as 726 neutral photographs. In Study 2, we aimed to validate the SFIP in a sample of spider, blood/injection, social-fearful, and control individuals (N = 66). The fear-relevant images were rated as being more unpleasant and led to greater fear and arousal in fearful than in nonfearful individuals. The fear images differentiated between the three fear groups in the expected directions. Overall, the present findings provide evidence for the high validity of the SFIP and confirm that the set may be successfully used in phobia research.