Doctoral Dissertation
University of Oregon

MEMORY AND FRAGMENTATION IN DISSOCIATIVE IDENTITY DISORDER

Margaret Rose Barlow
PhD
2005
Advisor Freyd, Jennifer J.

Dissertation Abstract

Dissociative identity disorder (DID), formerly called multiple personalities, is a condition in which aspects of experience and memory are separated from each other and from awareness. The current study adds to the literature in this area by utilizing a broad conceptualization of memory functioning in DID, combining ecologically valid memory tests with experimental paradigms, and examining shareability, switching, and integration. Eleven women with DID participated in a two-session experiment that included a variety of memory measures. Participants were given no instructions regarding switching among alters, but were later asked how often they had switched. They reported significantly higher levels of trauma than did a group of 13 female university students. DID participants were faster than student participants at producing autobiographical memories in response to cue words. DID participants also showed a decreased ability to answer detailed questions about a story containing fear, compared with a neutral story. This decrease did not appear in the student group. In a procedural learning task, DID participants improved more than did the student group on percentage of mirror-reversed words read correctly. Although these results were not statistically significant, effect sizes were moderate to high.

Shared and unshared autobiographical memories had similar properties, although in the DID group the unshared memories included significantly more taste imagery than did the shared memories. The student group scored significantly higher on a measure of overall memory than did the DID group. Percentage of alters who knew about the unshared memory was significantly negatively correlated with how long ago the memory was formed.

DID participants switched among alters an average of 5.8 times during the memory-testing session, and switching was highly correlated with high levels of lifetime betrayal trauma. This study also introduces the Integration Measure (IM), which is the first standardized measure of integration in DID. Integration was related to switching, though this relationship may be complex. Regression analyses demonstrated that lifetime high betrayal trauma was the best predictor of switching. Frequent switching may also slow reaction time in a variety of tasks. Directions for future research and suggestions for researchers are also di

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