The role of belief in memory amplification for trauma events

Background and objectives: Trauma survivors often report trauma events inconsistently over time. Many studies, for example, have found that people report having experienced trauma events that they initially failed to report or remember, a phenomenon called “memory amplification.” Other studies have found the opposite: people report experiencing fewer events over time. Nahleen, Nixon, and Takarangi (2019) asked participants at two time-points, with a six-month delay, whether they had experienced 19 sexual assault events on a yes/no scale. Participants reported fewer events over time, that is, memory for sexual assault did not amplify overall. In the current study, we assessed whether inconsistency in reports of trauma exposure over time may be attributed to changes in participants’ belief that certain events were experienced. Methods: We replicated Nahleen et al. (2019), but rather than respond to a yes/no trauma exposure scale, participants were required to rate the likelihood that each trauma event occurred on an 8-point scale (1 = definitely did not happen; 8 = definitely did happen). Results: We found that participants believed that they were less likely to have experienced the sexual assault events at follow-up compared to initial assessment. Limitations: We could not corroborate trauma experiences or determine causality with our design. Further, not all of our findings were consistent with Nahleen et al. (2019). Conclusions: Sexual assault memories did not amplify over time, perhaps because, compared to other types of trauma, the idea of experiencing additional sexual assault events that were not actually experienced is less believable.