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Abstract
Although anxiety disorders have traditionally been associated with maladaptive fear responses, there is growing awareness that other aversive states, in particular disgust and dislike, play an important role in anxiety. Given that the “gold standard” treatment for anxiety disorders, which involves gradual exposure to feared stimuli and situations, is explicitly based on extinction in the laboratory, extinction models have been a useful tool with which to examine anxiety disorders. A wealth of data suggests that fear responses reliably diminish in response to extinction and exposure. In contrast, research suggests that feelings of dislike towards feared stimuli remain following extinction, although the bulk of that evidence relies on self-report. Despite the central role of disgust in certain anxiety disorders, little is known about the loss of disgust reactions. Therefore, the aim of this research was to examine the extinction of evaluative responses, in particular, dislike and disgust, using both self-report and behavioural measures, in order to inform the treatment of anxiety disorders. Using a variety of assessment tools, including a promising new measure, visual avoidance, the experiments in the first experimental chapter examined residual dislike following fear conditioning and extinction. Those experiments demonstrated that feelings of dislike did not extinguish to the same extent as cognitive expectancy of threat and physiological fear responses. The next chapter examined disgust conditioning and extinction. The experiments in that chapter showed that disgust responses were also resistant to extinction and demonstrated that certain evaluative responses were retained over time whilst others were not. Finally, the last experimental chapter directly compared the extinction of learned fear and disgust within the same protocol. Although fear responses extinguished, disgust responses were again shown to be resistant to extinction, suggesting that differences in the extinction of these emotions are not due to procedural artifacts. This comprehensive examination of the extinction of evaluative responses suggests that current treatments for anxiety disorders may not adequately target disgust and dislike. This inattention to evaluative responses may reduce the effectiveness of treatment or may leave the patient vulnerable to relapse. Potential strategies to address these affective states are explored in the General Discussion.