Pergamon

Behac. Res. Thu. Vol. 32, No. I, pp. 141-746, 1994 Copyright 0 1994 Elsevier Science Ltd

00057967(93)EOOZl-V Printed in Great Britain. All rights reserved 0005-7967/94 $7.00 + 0.00

ROLE OF SELECTIVE RECALL IN THE

OVERPREDICTION OF FEAR

STEVEN TAYLOR’ and S. RACHMAN’

‘Department of Psychiatry and ‘Department of Psychology, 2255 Westbrook Mall, University of British Columbia, Vancouver, B.C., Canada V6T 2A1

(Received 5 November 1993)

Summary-Overprediction of fear is a bias in which phobic individuals tend to overestimate the amount of fear they will experience in a subjectively threatening situation. The selective recall model states that this bias arises because memories of highly fearful experiences are more easily retrieved than memories of nonfearful experiences. The model predicts that phobics should show a greater magnitude of overprediction if they receive fear-relevant priming compared with fear-irrelevant priming. A study of 100 spider-fearful Ss found that the magnitude of overprediction was smallest after fear-relevant priming, thus refuting the model. Alternative models are considered, and directions for further investigation are set out.

INTRODUCTION

Several studies have demonstrated that fearful people tend to overpredict the amount of fear they will experience in a subjectively threatening situation [see Rachman & Bichard (1988) for a review]. This bias can be demonstrated by measuring predicted fear and reported (experienced) fear on O-100 scales, anchored such that 0 = no fear, and 100 = terrifying fear. The S makes a prediction about the amount of fear to be evoked by a given stimulus, encounters the stimulus, and then reports the amount of fear that was experienced. The overprediction bias is of theoretical and clinical significance because fear-relevant expectations are known to be among the best predictors of avoidance behaviour in simple phobia and in panic disorder with agoraphobia (Rachman, 1990).

People may overpredict their fears because they overpredict the dangerousness of a threatening stimulus, and underpredict the sources of safety (e.g. escape routes) associated with the stimulus. This possibility is consistent with findings that anxious people tend to: (a) overpredict the probability of aversive events (Beck, Laude & Bohnert, 1974; Butler & Mathews, 1983; Lucock & Salkovskis, 1988); (b) underpredict the probability of pleasant events (Lucock & Salkovskis, 1988); and (c) neglect safety information when making fear predictions but not when making fear reports (Taylor & Rachman, 1991). Recently, we tested the hypothesis that the overprediction of fear arises from the overprediction of danger and underprediction of safety (Taylor & Rachman, 1994). 224 snake-fearful Ss were exposed to a live, harmless snake. Subjects made predictions and reports of their fear levels, in addition to predictions and reports of danger-relevant features (snake length, activity level and a global rating of dangerousness), and predictions and reports of safety-relevant features (control over whether the snake touched the S, and a global rating of safety). Subjects overpredicted their fears, overpredicted each of the danger-relevant features, and underpredicted each of the safety-relevant features (all Ps < 0.001). Structural equation modelling (“causal modelling”: Bollen, 1989) supported the hypothesis that biases in estimating the fear stimulus lead to the overprediction of fear.

These findings advance the understanding of the overprediction of fear, yet the question remains as to why fearful people tend to overpredict danger and underpredict safety. These biases may arise from distortions in the retrieval of threat-relevant memories. Rachman and Bichard (1988) proposed that fear predictions are based on memories of previous experiences, and so are influenced by the availability (ease of access) of memories of relevant experiences. Vivid emotion-arousing events, such as highly fearful experiences, tend to be more easily recalled than memories of pallid experiences (Tversky & Kahneman, 1973). Thus, the overprediction of fear may arise because of the selective retrieval of memories of experiences that were more threatening than those that the

741

742 STEVEN TAYLOR and S. RACHMAN

individual typically experiences. Implicit in this model is the assumption that selective recall has a greater effect on fear predictions than fear reports. The selective recall model holds that the overprediction of fear is most likely to occur when the individual has little information about the nature of the fear-stimulus that is about to be encountered, and so must draw on his/her stock of past experiences to make a fear prediction. The aim of the present study was to evaluate this model.

It has been argued that a priming task is the most appropriate method for testing models that rely on the concept of selective recall (availability~ (Gabrielcik & Fazio, 1984). Priming tasks influence the availability of material in memory. The availability of highly fearful memories can be enhanced by having Ss recall fear-relevant memories, and reduced by recalling fear-irrelevant memories. The effect of these procedures on subsequent predictions and reports of fear can then be examined. Rachman and Bichard’s (1988) selective recall model predicts that the magnitude of overprediction following fear-relevant priming will be greater than that following fear-irrelevant priming.

METHOD

Subjects

100 university students participated for course credit. Subjects were selected from a pool of over 1500 students who completed an abbreviated version of the Fear Survey Schedule III (Wolpe & Lang, 1964). Respondents who stated that they were “much”, or “very much’ afraid of spiders were selected for participation. The sample was 90% female, with a mean age of 19 yr (SD = I yr}.

Measures

All ratings were made on visual analogue scales, consisting of 100 mm lines divided into 5 mm gradations and labelled in increments of 10 mm. Scales were anchored such that 0 indicated the minimum quantity of the attribute in question, and 100 indicated the maximum. Each variable was measured by a single analogue scale since these scales require little time to complete, which reduces the chances that they would give rise to priming effects. This was deemed important, since scale-induced priming could cloud the effects of the experimental manipulations. The scales assessed pre-priming spider fear and mood-state (four scales: happy, sad, anxious and angry). The mood scales were included to further examine the effects of priming. Other visual analogue measures were used in the priming tasks and the predict-report task, and are described below.

Priming tasks

Fear-relevant priming. Subjects were asked to provide a written description of a memorable, highly fearful personal encounter with a spider. Subjects were asked to provide details about what had happened, where they were, what the spider looked like, their reactions, and their peak fear during the event. The latter was assessed by a visual analogue scale. After giving their description, the Ss answered several probe questions intended to enhance the saliency of the recollection. These called for descriptions of the spider (e.g. size, colour and activity level), the S’s cognitions, physiological reactions, and behavioral responses during the episode.

Fear-irrelevant priming. Subjects were asked to provide a written description of a memorable experience that was unrelated to spiders, Subjects were informed that this could be any event that stood out in memory, such as meeting an interesting person, going on a trip, or watching a good movie. Subjects were asked to provide details about what had happened, where they were, what the scene looked like, and their reactions. After providing this description, they answered several questions intended to enhance the saliency of the recollection, consisting of descriptions of the event (e.g. colours, sounds, shapes), the S’s cognitions, physiological reactions and behavioral responses during the episode.

Predict-report task

The selective recall model holds that the overprediction of fear is most likely to occur when there is uncertainty about the predicted stimulus. To provide an adequate test of the model, the

Overprediction of fear 743

predict--report task was designed to enhance this factor. In the case of spider fears, the fear-evoking stimulus can be regarded as a complex of features, consisting of a spider, the environment in which a spider might be found, and the task required of the S. Thus, the spider serves as a fear-evoking stimulus, as does a container that might house a spider. Stimulus uncertainty can be introduced by limiting the information about any or all of these features. The threat-value of this stimulus clearly depends on whether the spider is present or absent. Thus, a powerful way of introducing stimulus uncertainty is to make the presence of the spider a probabilistic event. This feature was incorporated into the present study.

The predict-report task consisted of a predictions questionnaire foltowed by an approach task. The predictions questionnaire was prefaced by a written description of the approach task. The S was informed that the task required him/her to approach a container located 3 m away at the end of the test room, then remove the container’s opaque cover, and touch the inside base of the container. The S was informed that the container either would be empty or contain a slow-moving spider that was 2 in wide, with a 50% chance of either event. After reading the instructions the 5’ predicted the level of fear when he/she was about to remove the cover. After completing the predictions, the S walked up to the covered container and made a rating of reported fear.*

Design and procedure

One group of Ss (n = 50) received fear-relevant priming and a second group (n = 50) received fear-irrelevant priming. Each S was tested individually and all instructions and rating scales were presented in booklet form. Informed consent was obtained prior to participation, and Ss were informed that they could discontinue the experiment at any time. The instructions and ratings were completed in the following sequence: (a) ratings of pre-priming spider fear and mood-state; (b) priming task (fear-relevant or fear-irrelevant); (c) re-rating of mood state; (d) predict-report task; and (e) debriefing.

Analysis procedures

The dependent variable used to test the experimental prediction was OP, defined as fear prediction-fear report. A difference score is necessary to operationally define the overprediction phenomenon, although it has a drawback in that it has a greater measurement error than its constituents, predicted and reported fear. This is because when a difference score is constructed the factors in common to the tests are cancelled out, leaving the true difference between the measures along with the SUM of the errors of measurement associated with each test (Thorndike & Hagen, 1977). The use of residuahzed scores reduces the error associated with difference scores (Cronbach & Furby, 1970). The difference between predicted and reported fear can be residuafized by using predicted fear as a covariate. Thus, the residuahzed difference score was expressed as #(predicted fear) - (reported fear)}, where pis a correction factor derived from a least-squares covariance analysis.

RESULTS

The groups did not differ in their pre-priming levels of spider fear or mood-state, Hotelling F(5.93) < 1 .OO, P > 0.1. The priming tasks did not differ in duration, F(1,98) < 1 .OO, P z=- 0.1; grand M = 10.2 min, SD = 2.7 min. The mean peak fear recalled in the fear-relevant condition was 86.2 (SD = 10.4), indicating that Ss were successful in recalling highly fearful experiences. The memories recalled in the fear-irrelevant condition were predominantIy pIeasant events.

*Subjects also predicted: (a) the level of fear when touching the inside base of the container (FP.,,,); (b) the level of fear when touching the inside base of the container if the spider was present (FP .,Ww); and (c) the level of fear when touching the inside base of the container if the spider was not present (FP.,,). The S also removed the cover and touched the inside base of the container and then reported his/her fear level (FR). A spider was never present in the container because the presence of a spider could increase the error variance of the fear reports, since the spider may sporadically move about in its container, increasing fear for some Ss but not for others. The difference score, FP.,, - FR, was computed and the priming effects were found to be essentially the same as those reported in the body of this article. The results described in this footnote are not discussed further since it may be objected that the empty container does not constitute a fear stimulus, whereas a covered container that might house a spider clearly is fear stimulus for spider phobics.

744 STEVEN TAYLOR and S. RACHMAN

The effects of priming on the overprediction of fear were examined by a one-way ANCOVA. The independent variable was the priming condition (fear-relevant vs fear-irrelevant). OP was the dependent variable and the covariate was the fear prediction. The priming main effect was significant, F( 1,97) = 5.54, P < 0.02. The fear-irrelevant group significantly overpredicted, t(48) = 2.05, P < 0.05 (A4 = 7.3, SD = 24.5) whereas the fear-relevant group were accurate in their predictions, t(48) < 1.00, P > 0.1 (A4 = -2.1, SD = 19.3). The priming groups did not differ in predicted fear, F( 1,98) = 1.05, P > 0.1, but did differ in reported fear, F( 1,98) = 6.62, P < 0.02. The fear-relevant group had significantly higher reported fear (M = 73.4, SD = 16.9) than the fear- irrelevant group (M = 61.7, SD = 27.3). The results are in the opposite direction to that predicted by the selective recall model. In the following sections we consider some possible explanations for these unexpected findings.

Ceiling eflects

Fear predictions tended to be higher than fear reports, at least in the group receiving fear-irrelevant priming. If fear predictions were more effected by ceiling effects then the present study would not provide an adequate test of the selective recall model since the true effects of priming on predicted fear, and hence overprediction, could not be determined. This possibility was addressed by a comparison of priming effects between Ss with high vs low levels of pre-priming spider fear. Ratings of pre-priming spider fear were subjected to a median split, and high and low fear groups were formed. A two-way ANOVA was performed. The independent variables were fear group (high vs low fear of spiders prior to priming) and priming condition (fear-relevant vs fear-irrelevant), and the dependent variable was predicted fear. The fear group main effect was significant, F(1,96) = 10.67, P < 0.002. Thus, the median split was successful in separating the Ss into groups that made either high or low fear predictions. With this division, the presence of ceiling effects would be demonstrated by a significant interaction between fear group and priming condition. This interaction was not significant, F(1, 96) < 1.00, P > 0.1. Thus, there was no evidence that the priming results were due to ceiling effects.

Mood-state

To investigate the effects of priming on mood-state, four one-way ANCOVAs were performed. The dependent variables were post-priming anxiety, happiness, sadness and anger. For each dependent variable the pre-priming scores on the same variable was used as a covariate. The priming conditions did not differ in post-priming sadness or anger, F(1,97) < 1 .OO, P > 1. Subjects receiving fear-relevant priming became more anxious, F( 1.97) = 15.76, P < 0.001, and less happy, F(1,97) = 19.57, P < 0.001, than those in the fear-irrelevant priming condition.

Zillmann’s (1983) transfer of excitation theory may be used to explain the effects of priming on reported fear by proposing that the effects of priming on mood were “transferred over” to influence the level of fear reported in the approach task. That is, the effects of priming on reported fear may have been mediated through the effects on mood, with the relatively greater state anxiety and lower state happiness in the fear-relevant priming condition producing greater levels of reported fear in the subsequent approach task. A one-way ANCOVA was performed to test this hypothesis. The dependent variable was reported fear and the independent variable was the priming condition (fear-relevant vs fear-irrelevant). The covariates were the post-priming ratings of state anxiety and state happiness. If the effects of priming on reported fear were due to changes in mood, then the covariates should be significant. Moreover, if mood mediated the effects of priming on reported fear, then matching the priming groups on post-priming mood (as per covariance analysis) should wipe out the effects of priming on reported fear. State anxiety was a significant covariate, F( 1,98) = 15.60, P < 0.001, but state happiness was not, F( 1,98) < 1 .OO, P > 0.1. With the inclusion of these covariates, the priming main effect was not significant, F(2,96) = 2.32, P > 0.1. The results are consistent with Zillmann’s (1983) theory, and suggest that the effects of priming on reported fear may have been mediated by state anxiety.

DISCUSSION

Fear-relevant priming, compared with fear-irrelevant priming, produced greater levels of reported fear, but did not influence predicted fear. Hence. the overprediction of fear was greatest

after fear-irrelevant priming, These results are contrary to the experimental predictions made by the selective recall model, and could not be attributed to ceiling efIects. Subjects were aware that, the study was concerned with the fear of spiders, and so there may have been an experimental demand to make high predictions and reports of this fear. This may be especially likely in the fear-relevant condition, since the recall of fear-relevant memories should enhance any demand to produce high fear ratings in the predict-report task. Yet priming influenced reported fear, not predicted fear. This is inconsistent with the argument that the results were due to experimental demand. It might be countered that another type of experimental demand was at work. where the priming manipulations influenced the 5s’ expectancies of the Froh~bility of encountering a spider. For example, fear-refevant priming may have conveyed the implicit message that a spider would have been present, and fear-irreleuant priming may have conveyed the opposite message. If this w&s the case, however, it would be expected that priming would influence both predictions and reports of fear. This was not found, Thus, it is concluded that the results were unlikely to have been due to experimental demand.

It is unlikely that our priming manipulations were insufficiently powerful to influence selective recall, A stronger form of priming is expected to have a greater influence on reported fear than on predicted fear, but is not expected to alter the pattern of rest&s revealed in the present study. It is possible that another version of the selective recall model could account for the overprediction of fear. The form that such a model would take is unclear. Moreover, it is difficult to see how a selective recall model could account for the overprediction of fear atrd the effects of priming.

Subjects overpredicted in the fear-irrelevant condition, which is consistent with the previously doc~jmented bias toward ov~~r~ictio~ {Rachman 22 &chard, 1988). Since priming increased reported fear but not predicted fear, overpred~ction did not occur in the fear-relevant condition. As mentioned, this may have arisen because priming increased state anxiety which, in turn, increased reported fear but not predicted fear.

Stcvte anxiety

What role does pre-exposure state anxiety play in the overprediction bias? If the transfer of pm-exposure state anxiety decrea,ses the overprediction bias, then the transfer of relaxation, or a transfer of a positive affective state that is incompatible with anxiety, may increase the magnitude of overprediction. This mechanism seems unlikely to account for the overprediction bias as it generally occurs, since the phobic Ss in previous overprediction studies made their fear predictions with knowledge that they were about to encounter a fear-evoking stimulus (Rachman & Bichard, 1988). Thus, they were unlikely $4 be in a relaxed or positive mood state. Indeed, they are more likely to be in a state of anticipatory anxiety.

The fact that priming did not influence fear predictions but did issuance state anxiety raises the question of whether Ss were aware that priming induced changes in state anxiety. It may be that increases in pre-exposure state anxiety do not attenuate the overprediction of fear when Ss are aware of these changes, since Ss may adjust their fear predictions accordingly. State anxiety may influence the overprediction of fear when pre-exposure anxiety is induced without the S’s awareness. When state anxiety is not manipulated in this way, it is unlikely to influence the overprediction of fear. Consistent with this, we recently found that preexposure state anxiety was not correlated with the magnitude of the overprediction of fear when experimental manipulations such as priming were not used (Taylor & Rachman, 1994). In all, our results suggest that pre-exposure state anxiety is unlikely to be a major det.e~in~nt of the over~rediction of fear.

~~~~~~~ & ~~~~~~~~~c~~~~

Finally, we consider some alternative models of the overpredictio~ of fear. One possibility is that fear predictions are influenced by the ease with which fear-relevant scenarios can be constructed, Kahneman and Tversky (1982) termed this the simuiation heuristic, Unlike the availability heuristic, which is based on the selective rem41 of episodic memories, the simulation heuristic is based on the generation of scenarios on the basis of one’s knowledge (semantic memories). The over- prediction of fear may arise if it is easier to construct terrifying scenat-ios compared with the ease of constructing low-fear scenarios. This couid occur if one acquires information that exaggerates the dangerousness of stimuli. U~~ortun~teiy, this model may have the same limitation as the

746 STEVEN TAYLOR and S. RACHMAN

selective recall model. That is, the priming of scenarios may have a greater effect on reported fear than on predicted fear, thus attenuating the overprediction bias.

Another model of overprediction draws from the research on selective attention (e.g. MacLeod, Mathews & Tata, 1986). The overprediction of fear may arise from cognitive operations that serve to facilitate avoidance or escape from aversive stimuli: (a) allocation of attentional resources to danger information at the expense of safety information when making predictions about the stimulus, thus motivating avoidance; and (b) allocating more attention to sources of safety (e.g. escape routes) when the feared stimulus has been encountered, thus facilitating escape. Measures of attention allocation (MacLeod et al., 1986) could be used to examine this possibility.

Further investigation is needed before recommendations can be made about how to reduce the overprediction bias in clinical practice. Since fear predictions motivate avoidance behaviour (Rachman, 1990) it may be possible to reduce excessive avoidance by training patients to predict more accurately. The form of training would depend on the mechanisms underlying the bias in predicting the feared stimulus. If the bias is due to selective attention, for example, then remedial attention-training procedures could be implemented. This practical implication suggests that the cognitive determinants of overprediction are an important subject for further investigation.

AcknoM?/edgements-The authors wish to thank Judy Zaparniuk for her valuable assistance. Address correspondence to Steven Taylor, Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, Canada V6T 2Al.

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