Covariation bias,classical conditioning,and phobic fear

The present study investigated whether phobics show an illusory correlation (IC) between phobia-relevant stimuli and aversive events. Nineteen treated and 19 untreated spider phobics were exposed to a series of 72 slides. Three different categories were used: Phobia-relevant slides (spiders), alternative fear-relevant slides (weapons), and neutral slides (flowers). Slides were randomly paired with either a shock, a siren, or nothing at all. All slide/outcome combinations occurred equally frequently. A posteriori recorded contingency estimates indicated that untreated phobics dramatically overestimate the covariation of spiders and shock. On-line recorded outcome expectancies revealed that the bias to overestimate the spider-shock contingency is highly resistant to extinction. The covariation bias was accompanied by differentially heightened electrodermal first interval responses (FIR) and unconditioned electrodermal responses (third interval responses: TIR) on phobia-relevant trials. Treated phobics did not show a covariation bias, indicating that such bias can be modulated by behavioral treatment. The present findings sustain the hypothesis that phobic subjects process information in a fear-confirming way.     

Covariation bias and electrodermal responding in spider phobics before and after behavioural treatment

The present study investigated whether a covariation bias is present in severe spider phobics and whether such bias is modified by successful treatment. In addition, this study sought to examine whether a covariation bias is linked to differential autonomic responding. Subjects were 20 untreated phobics, 19 treated phobics, and 18 no-fear controls. Subjects were exposed to a series of 72 slides comprising three categories: spiders (fear-relevant), mushrooms, and flowers. At slide offset one of three possible outcomes occurred: a shock, a tone, or nothing at all. All slide-outcome combinations occurred equally frequent. The results show that an equally strong covariation bias is present in severe spider phobics, in successfully treated phobics, and in no-fear controls. Thus, the present data only partially sustain earlier findings of Tomarken, A. J., Mineka, S. & Cook, M. (1989) (Journal of Abnormal Psychology, 98, 381-394). The covariation bias appeared to be mimicked by differentially heightened autonomic responding. The current data suggest that both the covariation bias and the heightened physiological responding reflect a "beloningness" between spider slides and aversive outcome.     

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.     

Fear-relevant selective associations and covariation bias

Three experiments used an illusory correlation paradigm to assess the effects of fear on the perception of the covariation between fear-relevant stimuli and shock. In Experiment 1, high- and low-fear women were exposed to 72 trials during each of which a fear-relevant (snake or spider) or fear-irrelevant (mushroom and flower) slide was followed by a shock, a tone, or nothing. Although the relation between slide types and outcomes was random, high-fear subjects markedly overestimated the contingency between feared slides and shock. Experiment 2 showed that this bias was due to the aversive, rather than more generally salient, features of shock. Low-fear subjects demonstrated biases equivalent to those of high-fear subjects only when the base rate of shock was increased from 33% to 50% in Experiment 3. It is concluded that fear may be linked to biases that serve to confirm fear. The relevance of the present findings to preparedness theory is also discussed.     

Dissociations between Covariation Bias and Expectancy Bias for Fear-relevant Stimuli

The illusory correlation paradigm of Tomarken, Mineka, and Cook (1989) was used to examine bias in threat appraisal for biological (snake, spider) and technological (gun, knife) fear-relevant stimuli. Subjects showed bias in terms of higher on-line shock expectancy ratings and skin conductance responses, and higher post-experimental judgements of shock covariation, for fear-relevant stimuli. However, there were multiple dissociations between the measures: (1) expectancy bias was observed for both biological and technological stimuli, whereas covariation bias was restricted to biological stimuli; (2) prior fear of the target stimulus had no effect on expectancy bias, but covariation bias was restricted to high fear subjects; and (3) covariation bias was observed at the end of the experiment, by which time expectancy bias had disappeared. These results suggest that covariation bias is not simply a continuation of a pre-experimental expectancy bias.     

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.     

Stability of Cognitive Bias for Threat Cues in Phobia

The present study examined whether the cognitive bias for threat is a stable phenomenon in spider phobics and not in nonphobic controls. The rationale of this study was that the use of emotional bias for individual assessment in clinical practice requires stability of this phenomenon. In order to assess the stability of the emotional bias, the spider Stroop task was administered twice to spider phobics and controls, with a time lag of 3 weeks. In two experiments, spider phobics (n_{exp. 1} = 20; n_{exp. 2} = 33) and controls (n_{exp. 1} = 24; n_{exp. 2} = 25) were selected on basis of a structured interview. In the second experiment, subjects anticipated exposure to a real-life spider. Emotional bias was inferred from color-naming latencies on spider words versus control words. In line with our prediction, the bias for threat was stable in spider phobic individuals but not in controls. This stability could not be attributed to a general cognitive characteristic because a standard Stroop task did not differentiate between the spider phobics and the controls. The results support the view that cognitive processing of threat in anxiety is stable. It is proposed to use both the emotional bias and its stability as measures of the constraints on the flexibility of the cognitive fear-network.     

Event-related potentials to schematic faces in social phobia

Social phobia has been associated with an attentional bias for angry faces. This study aimed at further characterising this attentional bias by investigating reaction times, heart rates, and ERPs while social phobics, spider phobics, and controls identified either the colour or the emotional quality of angry, happy, or neutral schematic faces. The emotional expression of angry faces did not interfere with the processing of their colour in social phobics, and heart rate, N170 amplitude and parietal late positive potentials (LPPs) of these subjects were also no different from those of non-phobic subjects. However, social phobics showed generally larger P1 amplitudes than non-phobic controls with spider phobic subjects in between. No general threat advantage for angry faces was found. All groups identified neutral schematic faces faster and showed larger late positive amplitudes to neutral than to emotional faces. Furthermore, in all groups the N170 was modulated by the emotional quality of faces. This effect was most pronounced in the emotion identification task.     

Phobia-relevant illusory correlations: the role of phobic responsivity

The authors investigated the role of phobic responsivity in the generation of phobia-relevant illusory correlations. As a means of disentangling the contributions of prior fear and elicited fear responses, half of a group of phobic women received 1 mg alprazolam (n = 21), and half received a placebo (n = 22). A group of nonfearful women (n = 24) was included to control for prior fear per se. Participants were exposed to slides of spiders, weapons, and flowers that were randomly paired with a shock, a siren, or nothing. Postexperimental covariation estimates and on-line outcome expectancies were assessed. Irrespective of both prior and elicited fear, participants postexperimentally overassociated spiders and shock. Yet, only women with spider phobia displayed a persisting fear-confirming expectancy bias. This bias was similar for the placebo and alprazolam groups. Thus, the bias appeared to be due to preexisting phobogenic beliefs, whereas phobic responsivity played a negligible role.     

Spider fear and covariation bias in children and adolescents

Covariation bias can be defined as phobic people's tendency to overestimate the association between fear-relevant stimuli and negative outcomes. The current article presents two studies that examined this type of cognitive bias in children and adolescents aged 8-16 years. Study 1 was concerned with a thought experiment during which youths (N=150) were asked to imagine that they participated in an experiment during which they had to view a series of pictures showing spiders, guns, and flowers, that were occasionally followed by a negative outcome (i.e., a mild electric shock). Participants were asked to estimate the relation between each type of picture and the negative outcome. The results indicated that youths with higher levels of spider fear displayed a specific tendency to relate spider pictures to a negative outcome. In Study 2, youths (N=220) actually participated in a computer game during which they were confronted with pictures of spiders, guns, and flowers, each of which was equally often followed by a negative (i.e., losing candy), positive (i.e., winning candy), or neutral outcome. After the game, participants had to estimate the relation between each type of picture and various outcomes. It was found that youths with higher levels of spider fear estimated more negative and less positive outcomes in relation to spider pictures. Taken together, these findings provide support for a fear-related covariation bias in youths. Further developmental analyses indicated that this type of cognitive bias seems to be more consistently present among adolescents than among children.     

Eye movements and behavioral responses to threatening and nonthreatening stimuli during visual search in phobic and nonphobic subjects

Spider-phobic and nonphobic subjects searched for a feared/fear-relevant (spider) or neutral target (mushroom) presented in visual matrices of neutral objects (flowers). In half of the displays, the mushroom target was paired with a spider distractor, or a spider target was paired with a mushroom distractor. Although all subjects responded faster to the neutral target than to the feared/fear-relevant target, phobics were slower to respond than nonphobics when a mushroom target was presented with a spider distractor. Their eyes appeared to be drawn to the feared distractor before fixating neutral targets. A further experiment indicated no group differences when subjects merely judged the homogeneity of matrices. Thus, threat seems to capture the attention of phobics only when it is part of a background that subjects are explicitly instructed to ignore.     

Psychophysiological and subjective reactions of social phobics and normals to facial stimuli

Nine social phobics and 9 normal control subjects were exposed to slides of angry faces, happy faces, and neutral objects (i.e. flowers or mushrooms). Skin conductance responses (SCRs) to the stimuli and eyeblink rate (EBR) during stimulus exposure were recorded. In addition, subjects were asked to rate the stimuli in terms of pleasantness. While angry face stimuli elicited greater SCRs, stronger inhibition of EBR, and were evaluated more negatively than the other stimuli, there were no differences between social phobics and normals in these respects. Thus, the findings lend no support to the idea that social phobics are particularly sensitive to facial cues in general or to negative facial cues in particular.     

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.     

Self-reported automaticity and irrationality in spider phobia

Spider phobic women (n = 39) and nonfearful controls (n = 41) completed a 20-item questionnaire measuring the extent to which they experience their fear reactions to spiders as automatic and irrational. For the phobic sample, therapy outcome data were also collected. Results suggest that spider phobics tend to view their attitude to spiders as irrational and in this respect, they do not differ from control subjects. Furthermore, compared to control subjects, phobics more often perceive their responses to spiders as automatic, i.e., not under intentional control. Contrary to expectation, no robust correlation was found between automaticity and irrationality. Interestingly, automaticity was not related to treatment outcome, while irrationality to some extent predicted therapy outcome (i.e., the more phobics experienced their fear as irrational, the more they profited from exposure treatment).     

Sensitivity and response bias in fear of spiders

According to cognitive theories of anxiety, phobic patients are searching the environment for threatening stimuli, and detecting them rapidly. However, previous studies failed to find a lowered perceptual threshold for threatening stimuli in specific phobias. Therefore, two experiments applying a signal detection paradigm were conducted. Highly spider fearful and nonfearful participants were asked to decide whether a picture of a spider, beetle, or butterfly was presented. In both experiments, spider fearfuls were not better at detecting spiders, or any other animal, than healthy controls. Instead, spider fearfuls were more liberal in assuming that they had seen a spider or a beetle. In accord with earlier studies, these results suggest that spider phobics may exhibit an interpretation bias rather than improved detection of threat.     

UCS expectancy biases in spider phobics: underestimation of aversive consequences following fear-irrelevant stimuli

This paper reports the results of two studies investigating judgements made by spider phobics about the potential threatening consequences (unconditioned stimulus, UCS, expectancies) associated with their phobic stimulus, fear-relevant (FR) stimuli, and fear-irrelevant (FI) stimuli. Using a 'thought experiment' UCS expectancy paradigm, the studies reported found that (1) spider phobics reported significantly higher UCS expectancies to spider stimuli than nonphobics, (2) spider phobics consistently underestimated the probability of aversive consequences following FI stimuli and (3) this underestimation of UCS expectancies to FI stimuli in phobics was not the result of a contrast effect resulting from sequential FR and FI judgements. This differential effect may have important implications for the kind of mechanism which mediates judgements about phobic consequences. These findings suggest that the dimensions on which phobic stimuli are categorised may be 'stretched' in the case of phobics and that this gives rise to the comparative underestimation of threat associated with FI stimuli but also makes phobics more vulnerable to acquiring other phobias.     

The potential role of state-dependent learning in cognitive therapy with spider phobics

Investigated the potential role of state-dependent learning in cognitive therapy with spider phobics. It was hypothesized that one strategy for increasing the effectiveness of cognitive therapy for anxiety would be to induce anxiety in subjects while they were learning the cognitive restructuring principles (i.e., during treatment). Thirty-two undergraduate volunteers were randomly assigned to one of six experimental conditions. Subjects in the five treatment conditions (the sixth was a no-treatment control condition) met for three sessions of cognitive restructuring,in vivo exposure, or a facts lecture (i.e., the placebo group). Results indicated that when working with spider phobics, three sessions of cognitive restructuring,in vivo exposure, or a facts lecture resulted in equal effectiveness immediately following treatment, but are more effective than no-treatment at all.     

Thinking high but feeling low: An exploratory cluster analysis investigating how implicit and explicit spider fear co-vary

Research has demonstrated large differences in the degree to which direct and indirect measures predict each other and variables including behavioural approach and attentional bias. We investigated whether individual differences in the co-variance of “implicit” and “explicit” spider fear exist, and whether this covariation exerts an effect on spider fear-related outcomes. One hundred and thirty-two undergraduate students completed direct and indirect measures of spider fear/avoidance, self-report questionnaires of psychopathology, an attentional bias task, and a proxy Behavioural Approach Task. TwoStep cluster analysis using implicit and explicit spider fear as criterion variables resulted in three clusters: (1) low explicit/low implicit; (2) average explicit/high implicit; and (3) high explicit/low implicit. Clusters with higher explicit fear demonstrated greater disgust propensity and sensitivity and less willingness to approach a spider. No differences between clusters emerged on anticipatory approach anxiety or attentional bias. We discuss results in terms of dual-systems and cognitive–behavioural models of fear.     

Questionnaire dimensions of spider phobia: a replication and extension

Two studies are presented in this paper. The first presents an analysis of an extended version of the Spider Phobia Questionnaire (SPQ), which can be used to assess cognitive, behavioural and physiological aspects of responsiveness to spiders in spider phobics. The second examines the relationship between these measures and measures of behavioural avoidance, subjective anxiety and physiological response in high and low fear subjects during an avoidance test. The lack of an expected relationship between the two sets of measures is 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.