Fear and disgust processing during repeated exposure to threat-relevant stimuli in spider phobia

Although disgust plays a significant role in the etiology of spider phobia, there remains a paucity of research examining the role of disgust in the treatment of spider phobia. Spider fearful participants (N = 46) were randomly assigned to a disgust (view vomit images) or neutral activation (view inanimate objects) condition. They were then repeatedly exposed to a videotaped tarantula, during which time their fear, disgust, and physiological levels were assessed repeatedly. Growth curve analyses indicated that repeated exposure led to significant declines in fear and disgust with no statistically significant differences between the two conditions. However, there was marginal evidence for decreased physiological arousal during repeated exposure among spider fearful participants in the disgust activation condition compared to those in the neutral condition. Reduction in disgust during exposure in the disgust activation condition remained significant after controlling for change in fear, whereas change in fear was no longer significant after controlling for change in disgust. However, the opposite pattern of relations between change in fear and disgust was observed in the neutral activation condition. Higher fear and disgust activation during exposure was also associated with higher fear and disgust responding on a subsequent behavioral task and higher spider fear and disgust at 3-month follow-up. Baseline trait disgust propensity also predicted fear and disgust parameters during repeated exposure. The implications of these findings for the role of disgust in the treatment of spider phobia are discussed.     

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.     

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.     

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.     

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.     

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.     

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.     

The spread of fear: Symbolic generalization mediates graded threat-avoidance in specific phobia

Overgeneralization of fear and threat-avoidance represents a formidable barrier to successful clinical treatment of anxiety disorders. While stimulus generalization along quantifiable physical dimensions has been studied extensively, less consideration has been given to symbolic generalization, in which stimuli are indirectly and arbitrarily related. The present study examined whether the magnitude and extent of symbolic generalization of threat-avoidance and threat-beliefs differed between spider-phobic and nonphobic individuals. Initially, participants learned two sets of stimulus equivalence relations (A1?=?B1?=?C1; A2?=?B2?=?C2). Next, one cue (B1) was established as a conditioned stimulus (CS?+?; threat) that signalled onset of spider images and prompted avoidance, and another cue (B2) was established as a CS– (safety cue) that signalled the absence of such images. Subsequent testing showed that phobics compared to nonphobics exhibited greater symbolic generalization of threat-avoidance to threat cues A1 and C1 (indirect CS+ threat cues related via symmetry and equivalence, respectively), while all individuals showed nonavoidance to indirect safety cues A2 and C2. The enhanced symbolic generalization of threat-beliefs and avoidance behaviour observed in spider phobics warrants further investigation.     

Repeated exposure of flight phobics to flights in virtual reality

The present study examined the effects of repeated exposure of flight phobics to flights in virtual reality (VR). Flight phobics were randomly assigned either to complete one VR test flight followed by four VR exposure flights (VR group; N=15) in one lengthy session or to complete one VR test flight followed by a lengthy relaxation training session (relaxation group; N=15). All participants completed a second VR test flight at the end of the session. Fear reports and physiological fear reactions (heart rate, skin conductance level) during VR exposures were registered, and fear of flying was assessed psychometrically from 3 weeks before to 3 months after exposure. Exposure to VR flights elicited subjective and physiological fear responses in flight phobics, and these responses attenuated within and across VR flights. Fear reduction associated with repeated VR exposure was greater than fear reduction caused by relaxation training. Fear of flying improved in both treatment groups, but several outcome measures indicated greater effects in the VR treated group than in the relaxation group. These findings indicate that exposure in virtual reality may offer a new and promising approach for the treatment of fear of flying.     

Very brief exposure II: the effects of unreportable stimuli on reducing phobic behavior

This experiment compared the effects of exposure to masked phobic stimuli at a very brief stimulus-onset asynchrony on spider-phobic and non-phobic individuals. Participants were identified through a widely used questionnaire and a Behavioral Avoidance Test (BAT) with a live, caged tarantula to establish baseline levels of avoidance. One week later, they were individually administered one of two continuous series of masked images: spiders or flowers. Preliminary masking experiments showed that independent samples of participants from the same populations failed to recognize these stimuli. Participants in the main experiment reported ratings of subjective distress immediately before and after the exposure manipulation. Then they engaged in the BAT once again. Very brief exposure to images of spiders reduced phobic participants' avoidance of the tarantula. No effects were evidenced on subjective distress, or on non-phobic participants. Theoretical implications for the non-conscious basis of fear are discussed.     

Animal phobias versus claustrophobias: Exteroceptive versus interoceptive cues

The overall purpose of this investigation was to examine heterogeneity among specific phobias. In particular, the goals were to compare features of fear responding between individuals fearful of claustrophobic situations and individuals fearful of spiders/snakes, and to compare their response to hyperventilation challenges. By so doing, specific predictions were tested in relation to a conceptual model of exteroceptive and interoceptive fear cues. Using a nonclinical sample, 19 subjects with spider/snake phobias, 18 nonphobies, and 9 subjects with claustrophobias were exposed on two separate occasions to a live tarantula or python, a small closet, and a hyperventilation challenge. Dependent measures included subjective anxiety, panic attacks, physical symptoms, cognitive symptoms (or, fear of symptoms) and heart rate. In addition, subjects completed a standardized self-report scale that measures fear of bodily symptoms of arousal. It was found that subjects with claustrophobia reported more physical symptoms and cognitive symptoms than did subjects with snake/spider phobias, in response to their fear-relevant stimulus. In addition, claustrophobic subjects were more fearful of hyperventilation challenges and reported more fear of bodily symptoms, than did snake/spider phobic subjects. Finally, subjects with claustrophobia were as fearful of hyperventilation as they were of their fear-relevant stimulus. Theoretical and empirical implications of these findings are discussed.     

What you cannot see can help you: the effect of exposure to unreportable stimuli on approach behavior

We examined effects of exposure to unreportable images of spiders on approach towards a tarantula. Pretests revealed awareness of the stimuli was at chance. Participants high or low (top and bottom 15%) on fear of spiders were randomly assigned to receive computer-generated exposure to unreportable pictures of spiders or outdoor scenes. They then engaged in a Behavioral Approach Task (BAT) with a live tarantula. Non-fearful participants completed more BAT items than spider-fearful individuals. Additionally, as predicted, a significant interaction (F(1,48)=5.12, p<.03) between fear of spiders and stimulus demonstrated that spider-fearful participants exposed to spiders completed more BAT items than spider-fearful participants exposed to control stimuli (but not as many as non-fearful participants). The findings support the hypothesis that exposure to unreportable feared stimuli promotes approach towards the feared object. Future research and clinical implications were discussed.     

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.     

Very brief exposure: The effects of unreportable stimuli on fearful behavior

A series of experiments tested the hypothesis that very brief exposure to feared stimuli can have positive effects on avoidance of the corresponding feared object. Participants identified themselves as fearful of spiders through a widely used questionnaire. A preliminary experiment showed that they were unable to identify the stimuli used in the main experiments. Experiment 2 (N = 65) compared the effects of exposure to masked feared stimuli at short and long stimulus onset asynchronies (SOA). Participants were individually administered one of three continuous series of backwards masked or non-masked stimuli: unreportable images of spiders (25-ms SOA), clearly visible images of spiders (500-ms SOA), or unreportable images of trees (25-ms SOA). Immediately thereafter, they engaged in a Behavioral Avoidance Test (BAT) with a live, caged tarantula. Exposure to unreportable images of spiders resulted in greater approach towards the tarantula than unreportable neutral images. A post-hoc comparison with clearly visible exposure to these same images approached significance. These effects were maintained at a 1-week follow-up (N = 57). In Experiment 3 (N = 26), participants engaged in the BAT 1 week prior to the exposure manipulation in order to provide a baseline measurement of their avoidant behavior, and again immediately after the exposure manipulation. Exposure to unreportable images of spiders reduced avoidance of the tarantula. Similar exposure to trees did not. Implications for the non-conscious basis of fear are discussed.     

Imagery ability and exposure in vivo in spider phobia

The present study deals with the effect of imagery ability on treatment outcome in spider phobias. Thirty-eight spider phobics completed the Questionnaire on Mental Imagery (QMI) and the Spider Questionnaire (SPQ). Subjects also went through a behavioral approach task (BAT) during which heart rate and avoidance behavior were measured. Each subject was then given one-session treatment as described by Ost. Immediately after treatment, SPQ and BAT data were again obtained. On the basis of their QMI scores, subjects were assigned to a 'good', 'moderate', or 'poor' imagers group. Neither pre-treatment nor post-treatment measures were found to vary as a function of imagery ability. Thus it appears that, at least for specific phobias such as spider fear, imagery ability is not a relevant variable for predicting the effects of in vivo exposure.     

Inhibition of fear acquisition in toddlers following positive modelling by their mothers

The present study used an experimental design to investigate the role of modelling as a protective factor in fear and avoidance learning in a sample of 77 toddlers. Mothers and their 12-20-month-old children were randomly assigned to one of three pre-exposure conditions: (1) a modelling group (n=27) observed their mothers responding positively to a fear-relevant stimulus; (2) a stimulus-only group (n=25) were exposed to a fear-relevant stimulus alone; and (3) a control group (n=25) were exposed to neither modelling nor the stimulus alone. Children in all three groups were then subjected to an observational conditioning trial in which the experimenter reacted with fear and disgust toward the stimulus. When subsequently tested for the acquisition of fear, children in the modelling group showed more positive affective reactions and more approach behaviours than either controls or children exposed to the stimulus alone. The results demonstrate that very young children can rapidly form lasting associations between maternal affective reactions and novel, fear-relevant stimuli. Further, positive maternal reactions to a stimulus can over-ride any fear-evoking effect of negative reactions to that stimulus by a stranger.     

The effect of very brief exposure on experienced fear after in vivo exposure

Two experiments tested the effect of exposure to masked phobic stimuli at a very brief stimulus onset asynchrony on reducing the subjective experience of fear caused by in vivo exposure to a feared object. In the main experiment, 35 spider-fearful and 35 non-fearful participants were identified with a questionnaire and a Behavioural Avoidance Test (BAT) with a live tarantula. One week later, they were individually administered one of two continuous series of masked images: spiders or flowers. They engaged in the BAT again immediately thereafter. They provided ratings of subjective fear at the end of each BAT (pre- and post-manipulation). Very brief exposure to images of spiders reduced the fearful group's and not the non-fearful group's experience of fear at the end of the BAT. This effect was replicated with another sample of 26 spider-fearful participants from the same population. Theoretical implications are discussed.     

Reliability and validity of some specific fear questionnaires

Normative psychometric data on a Swedish translation of fear questionnaires concerning snakes, spiders, public speaking, and mutilation given to 223 college students are presented. High internal consistencies were found for all four questionnaires, and low intercorrelations among the four inventories emerged. In a separate study the inventories were administered to a clinical sample of spider and snake phobics. Phobics scored higher on their respective phobic scale than the college group but did not differ from controls on mutilation or public speaking scales. A significant negative correlation emerged between snake and spider scores among the phobics. One year test-retest reliabilities in the phobic sample were high. Finally, snake and spider phobics viewed and rated phobic and nonphobic slides. Snake phobics rated snake slides as more aversive than spider slides, whereas the reverse was true for spider phobics. The correlation between fear ratings and questionnaire scores was significant. Use of these scales in evaluating therapeutic changes is encouraged.     

A test of a disease-avoidance model of animal phobias

This study examined the relationship between disgust/contamination sensitivity and fear of animals. The results suggested that sensitivity to disgust and contamination was directly related to scores on the animal phobia and fear of illness and death sub-scales of the Fear Survey Schedule (FSS). Further analysis suggested that disgust/contamination sensitivity was related only to fear of certain groups of animals: namely those animals that are not considered to attack and harm human beings but are considered fear-evoking (e.g. rat, spider, cockroach), and those animals that are normally considered to evoke revulsion (e.g. maggot, snail, slug). Disgust/contamination sensitivity was not related to fear of animals that are considered highly likely to attack and harm human beings (e.g. tiger, lion, shark). These results are discussed as support for a disease-avoidance model of common animal fears.