An Investigation into the Mechanisms Underlying the Memory Amplification Effect

Author: Sasha Quayum

Quayum, Sasha, 2019 An Investigation into the Mechanisms Underlying the Memory Amplification Effect, Flinders University, College of Education, Psychology and Social Work

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Field research shows that trauma survivors sometimes report experiencing more trauma at follow-up compared to initial assessment. There is limited research regarding why this “memory amplification” occurs. I investigated three potential explanations for amplification.

First, because amplification is positively related to higher PTSD symptom severity, one possibility is that amplification arises from a reappraisal process: people may appraise the trauma event and past symptoms as worse than initially reported to make sense of, or justify, current symptomatology; therefore, traumatic events initially considered minor may be relabeled as significant. Consistent with this proposal, and with field data, my findings in Studies 1, 2, 3, and 4 show distress at follow-up is related to memory amplification errors. Further, in Studies 1, 2, and 3, participants with higher symptom levels made comparatively more amplification errors than participants with lower symptom severity. Interestingly, in Studies 3 and 6, I also found evidence that reappraising trauma as less important over time may be an adaptive adjustment mechanism that helps people regulate distress or vice versa.

A second possibility I examined is that amplification is caused by exposure to post-event information. Field amplification studies have usually investigated memory for large-scale events (e.g., war), after which people are likely to encounter new information, for example, in media reports. Numerous studies show post-event information can distort memory, likely because it shares similar details to the original event. Overlap in characteristics of memories from two sources can lead to source monitoring errors, resulting in the post-event information being inadvertently incorporated into original event memory. In Study 1, people who were exposed to media reports about their experiences and similar experiences made more amplification errors compared to those who were not. Further, in a series of analogue experiments in Study 4, participants falsely remembered more trauma photos after post-event information exposure, suggesting that they inadvertently incorporated post-event information into their memory. Further, I found improving source monitoring with subtle warnings and source tests made participants resistant to inaccurate post-event information, suggesting that source monitoring is an underlying mechanism of amplification.

Third, trauma experiences investigated in amplification studies are often shared (e.g., soldiers in a unit). Recent research shows that sharing an experience with another person, even without communication, can enhance or amplify that experience. Therefore, a third possible mechanism for memory amplification is that people construct mental representations of others' responses (perspective-taking) and spontaneously incorporate them into their own responses. Indeed, my findings in Studies 5 and 6 suggest that aspects of shared stressful experiences can amplify, becoming more negative, compared to when the same experiences are not shared. I also found some evidence that this shared amplification may occur because of perspective-taking.

My thesis adds to a growing body of literature showing trauma memory can be inconsistent and inaccurate. Further, my findings support Rubin, Berntsen, and Bohni’s (2008) memory-based PTSD model, which posits that trauma memory will be distorted by factors like current goals and concerns. Overall, my findings provide some support for all three explanations of memory amplification.

Keywords: memory, trauma, PTSD

Subject: Psychology thesis

Thesis type: Doctor of Philosophy
Completed: 2019
School: College of Education, Psychology and Social Work
Supervisor: Dr Melanie Takarangi