The influence of ruminative processing mode on the trajectory of intrusive memories following a negative mood induction

Background and objectives: Rumination following an event, particularly in an abstract as opposed to concrete processing mode, is associated with increased intrusive memory frequency. However, the temporal trajectory of intrusive memories following abstract and concrete rumination remains unclear. We examined the association between processing mode and the frequency of intrusive memories over a 6-h time period following a negative mood induction. Methods: One hundred and sixteen community participants watched a video sequence designed to induce negative mood. Participants were then randomised into condition (abstract, concrete or distraction) and completed a verbally mediated task designed to induce the respective processing mode. Participants then completed hourly ratings of rumination and intrusive memories about the video after leaving the laboratory. Results: Negative mood and intrusive memories were reliably induced. There were no differences in the frequency of intrusive memories between the abstract and concrete conditions. In contrast, participants in the distraction condition reported significantly more sensory intrusive memories than either ruminative condition. Three classes were found among participants following the video (intrusion free, rapid remitters, slow remitters). Condition was not predictive of class membership. Limitations: It cannot be ruled out that the differences between rumination and distraction conditions were due to task differences. Conclusions: In contrast to previous findings, our results suggest that any form of rumination about an event (whether in an abstract or concrete mode) may temporarily result in fewer intrusive memories in comparison to distraction. Processing mode does not appear to predict particular trajectories of intrusions following a mood induction.