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UBC Theses and Dissertations

The overprediction of fear Taylor, Steven


Stimulus and response expectations play a central role in cognitive formulations of fear and avoidance. Research on this subject has been primarily concerned with the identification of various forms of expectations and their associated biases. Comparatively little is known about the cognitive structures or processes that produce biased expectations. The studies reported in this dissertation were intended to investigate the mechanisms of one bias of fear expectations, the overprediction of fear. This is a common phenomenon in which fearful people tend to overestimate the amount of fear that they will experience upon exposure to a threatening stimulus. Although overprediction is of interest in its own right, it is also important in that it promotes excessive avoidance behaviour, and so contributes to the maintenance of fear. A theoretical framework, called the stimulus estimation model, was proposed for conceptualizing the overprediction of fear. This model consists of an algebraic expression of the elements of overprediction and a set of candidate cognitive mechanisms that generate the algebraic relations. The essence of the algebraic expression is that the overprediction of fear arises from the overprediction of the threatening elements of the feared stimulus, and the underprediction of the elements that confer safety. One of the cognitive components of this model, the selective recall model, states that overprediction arises from the selective retrieval of memories of highly fearful reactions to aversive events. Another cognitive component, the differential-weighting model, proposes that overprediction arises because environmental information about sources of safety has a greater influence on reported fear than on predicted fear. The first experiment tested the selective recall model with a priming paradigm. One group of 50 spider-fearful subjects was required to recall highly fearful encounters with spiders (fear-relevant priming). A second group of 50 spider-fearful subjects was required to recall spider-irrelevant experiences (fear-irrelevant priming). The selective recall model predicts that the overprediction of fear in a subsequent fear-evoking task would be greatest after fear-relevant priming compared with fear-irrelevant priming. Contrary to expectation, predicted fear did not differ between the priming conditions. Reported fear was greatest after fear-relevant priming. Thus, contrary to the selective-recall model, the magnitude of overprediction was smallest in the fear-relevant priming condition. The second experiment tested the differential-weighting model. One hundred and twenty-one spider-fearful subjects were randomly allocated to one of two groups. One group received minimal safety information about a fear-evoking task. The second group received a high level of safety information about the task. It was found that the groups did not differ in their fear predictions, but the high information group made lower fear reports than the low-information group. As a result, the provision of safety information increased the magnitude of overprediction, thus supporting the model. The third experiment attempted to replicate and extend the findings of Experiment 2, using a sample of 224 snake-fearful subjects. Danger and safety information were compared in their effects on predictions and reports of fear. All information effects were nonsignificant. The results of further analyses suggested that this was due to inadequate experimental manipulations rather than to an inadequacy in the model. The algebraic expression of the stimulus estimation model was supported by a series of analyses, including structural equation modeling. Thus, in the case of the fear of snakes, support was found for the hypothesis that the overprediction of fear is caused by overpredictions of the dangerousness, activity level, and size of the snake, and underpredictions of the safety and controllability of the situation. In the final chapter, the utility of the stimulus estimation model was considered, implications for other fear-relevant phenomena were set out, and directions for further investigation were explored.

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