An Experimental Investigation of the Causal Role of Mental Imagery in the Experience of Involuntary Memories

Involuntary memories are thought to affect emotion, cognition, and behaviour, and it is often assumed that their impact is amplified when they are rich in mental imagery. However, this assumption has yet to be directly investigated. The current study tested a newly-developed paradigm designed to induce involuntary memories and provide a means to test the role of mental imagery directly. In a within-subject design, an unselected young adult (mostly student) sample (N = 53) participated in a lab-based study. Participants generated emotionally-valenced mental images or sentences via combining ambiguous pictures with positive or negative word captions. They then completed tasks designed to trigger involuntary memories of the previously generated images and sentences. Voluntary retrieval of the picture-word pairs was also assessed. Participants reported experiencing involuntary memories of previously generated images and sentences, but there were no detectable effects of mental imagery on measures of involuntary memory. However, participants recalled more word captions from picture-word pairs used to generate images than those used to generate sentences. Overall, the newly developed paradigm provides a means to test assumptions about the impact and functions of involuntary memories directly via experimental manipulation, opening up a number of opportunities for future research.