Investigating the frequency of intrusive memories after 24 hours using a visuospatial interference intervention: a follow-up and extension

Background: There is a need for effective, low-cost, readily available measures for reducing trauma symptoms so that people exposed to potentially traumatic events can receive help more quickly. A previous study reported that performing an intervention including a visuospatial task shortly after a reminder of a series of unpleasant film clips seen 24 hours earlier reduced the number of intrusive memories over the following week. Objective: This study reports a follow-up and extension of the earlier promising finding. The prediction was that participants performing the visuospatial task immediately after the reminder would report fewer intrusions compared to three other groups who 1) performed no task, and novel conditions who 2) performed the task before the reminder, and 3) performed the task 90 minutes after the reminder. Method: A trauma-analogue method was used, where students (N = 200) watched a series of short films with unpleasant material. Over the following week, they were asked to write down any intrusive memories they experienced in a diary. On the second day they returned to the lab and saw static reminders of the films. They were then randomly allocated to condition, recorded intrusive memories over the following days and returned to the lab for final testing on Day 8. Results: A total of 49 participants did not report any intrusions and were excluded from the analyses. Two more participants were excluded as outliers, leaving a final sample of n = 149. Despite using largely the same materials as the original study there were no significant differences in the number of intrusive memories between the four groups post intervention. Conclusions: Possible explanations include the effect not being as robust as expected, a low number of intrusions across groups, baseline differences in attention, and minor but potentially important differences in procedure between this and the original study.