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Abstract
Current theories of dissociation are deficient, in that diverse symptoms are grouped under one global classification. This thesis used a multi-pronged approach employing clinical and analogue studies to deconstruct one commonly reported peritraumatic dissociative symptom: time distortion. Study 1 tested the proposal that time slowing during a traumatic event would be associated with the development and maintenance of Posttraumatic Stress Disorder (PTSD). The findings indicated that peritraumatic time slowing was associated with more severe PTSD symptoms and a threefold increase in the probability of PTSD three months later. Study 2 examined qualitative aspects of time distortion experience during traumatic events. The results indicated that time slowing was linked with the anticipation of aversive outcomes of the event. Study 3 tested the hypothesis that increased arousal would be associated with overestimates of stimuli duration. The findings indicated that higher levels of arousal were associated with longer time judgments. Study 4 investigated hyperarousal in a naturalistic setting involving extreme stress in skydivers. Higher ratings of fear were associated with a tendency to overestimate event duration. Study 5 investigated hypnotically-induced temperature change and time perception. The results indicated that highly hypnotisable hypnotised participants overestimated stimuli duration following a warming suggestion. Studies 6a, 6b, 7 and 8 investigated whether emotional material was perceived differently to non-emotional material. Studies 6a and 6b demonstrated that the duration of emotionally negative material was overestimated relative to neutral or positive material. Study 7 examined the combined effect of valence and physiological arousal on time perception. The results suggested that arousal mediated the effect of valence on time perception. Study 8 employed clinical and non-clinical samples to investigate time perception for autobiographical memories. The results indicated that people currently experiencing PTSD indexed greater estimates of trauma memory duration. Study 9 examined the effect of perception of control on duration estimates. The results suggested that perceived lack of control over negative stimuli was associated with longer duration estimates. Together, the findings supported and extended existing models of time perception, and demonstrated that time distortions appear to be influenced by arousal, emotional valence, and avoidance reactions.