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The effect of distraction on fear reduction during In Vivo exposure for Spider-fearful individuals: Exploring the relationship between fear level and distraction load

Ellis, Samantha (2012) The effect of distraction on fear reduction during In Vivo exposure for Spider-fearful individuals: Exploring the relationship between fear level and distraction load. Professional Doctorate thesis, Murdoch University.

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Exposure-based therapy is currently the treatment of choice for a number of specific phobias (Antony & Barlow, 2002). While a myriad of studies have been conducted investigating exposure characteristics, such as frequency and duration, or comparing exposure to other forms of treatment, few studies have investigated the mechanisms of change underlying fear reduction. The emotional processing model (Foa & Kozak, 1986, 1998) claims that full attention to the feared stimulus during exposure is required for fear reduction to take place. However, some studies have found that directing attention away from the feared stimulus can facilitate greater and more rapid fear reduction than exposure, where attention is directed toward the phobic stimuli (Johnstone & Page, 2004; Oliver & Page, 2003, 2008; Penfold & Page, 1999). Further, some studies have observed an interaction between fear level and distraction load, whereby high levels of fear benefit more from high-load distracters, while low levels of fear benefit more from low-load distracters or no distraction at all (Johnstone & Page, 2004, 2007c; Penfold & Page, 1999).

Study 1 investigated jointly the roles of distraction load, operationalised using a continuous performance task (CPT) and fear level over time with a sample of spider-fearful individuals. Specifically, it was hypothesised that fear level and distraction load would interact, such that participants with relatively high levels of stimulus-bound fear in exposure one would benefit more from a high-load distracter, while those with relatively low stimulus-bound fear in exposure two would benefit more from a low-load distracter. Contrary to the emotional processing model’s prediction, results demonstrated that treatment was effective for all groups, regardless of distraction load, as evidenced by within- and between-exposure session reductions in fear (as assessed by self-report, behavioural, and physiological measures of fear). Subjective ratings of anxiety demonstrated partial support for the fear level-distraction load interaction. However, results were contaminated by practice effects of the distracter for the groups with constant load across both exposure sessions and by the relatively low anxiety sample used.

Study 2 aimed to overcome the practice effects of the distraction tasks observed in Study 1 for individuals repeating the same counting task for both exposure sessions. A CPT was used to operationalise new counting tasks. These new tasks were confirmed to load equally on working memory, providing a more consistent load than that used in Study 1.

Study 3 applied the newly operationalised counting-based distraction tasks to a higher anxiety sample of spider fearful subjects in a replication of Study 1. It was again predicted that all groups would experience a reduction in fear, further supporting the beneficial effects of distracted exposure, and that the fear level-distraction load interaction would be demonstrated. Support for distracted exposure was found with both within- and between-exposure session reductions on most indices for all groups. The interaction was partially supported, as evidenced by blood pressure ratings. However, this trend did not generalise to other measures, which was attributed to
desynchrony between the physiological, subjective, and behavioural response systems. Results indicated that fear reduction can occur under distracted conditions, but did not offer consistent support for the fear level - distraction load interaction. Results are discussed with respect to both their theoretical contribution to the literature on the processing of phobic stimuli and to their implications for clinical practice.

Item Type: Thesis (Professional Doctorate)
Murdoch Affiliation(s): School of Psychology
Supervisor(s): Dziurawiec, Suzanne, Davis, Helen and Johnstone, Kristy
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