| Journal of Behavior Therapy and Experimental Psychiatry
Unconscious Thought Reduces Intrusion Development: A Replication and Extension
Background and Objectives: Intrusive images after a traumatic event, a hallmark feature of post-traumatic stress disorder, are suggested to develop because the trauma memory is disorganized and not integrated into autobiographical memory. Unconscious Thought Theory predicts that information can be conceptually organized after a period of unconscious thought (UT), more so than after conscious thought (CT). We aimed to test the hypothesis that UT decreases intrusions and increases conceptual organization in memory. Methods: Participants were shown a stressful film and were required to perform an UT task, a CT task, or a distraction task. Intrusions of the film, intrusion qualities, and sequence memory were measured afterwards. Results: We confirmed our hypothesis that UT (versus CT or mere distraction) leads to fewer intrusions, thereby replicating earlier research. Contrary to prediction, we found no difference between the conditions on sequence memory. In addition, conscious thought appeared to increase intrusion nowness and arousal. Limitations: The analogue design and healthy participant sample prevent from generalizing results to other populations. Intrusion frequency and qualities were assessed immediately after the film thereby prohibiting us from drawing conclusions about any long-term effects. Conclusions: Engaging in unconscious thought after a stressful film can reduce intrusion frequency. This has potential implications for clinical interventions to prevent initial stress symptoms. The underlying mechanism remains unclear for now and provides an avenue for future research.