Inducing positive involuntary mental imagery in daily life using personalized photograph stimuli

Most people experience positive involuntary mental imagery (IMI) frequently in daily life; however, evidence for the importance and effects of positive IMI is largely indirect. The current study adapted a paradigm to experimentally induce positive IMI in participants' daily lives. This could in turn provide a means to directly test positive IMI's effects. In a within-subjects design, participants (N = 41) generated positive mental images (imagery condition) and sentences (verbal condition) from photo cues, half of which participants provided from their own living environment. Participants then recorded involuntary memories of the previously generated images or sentences in a seven-day diary, before returning to the lab and completing some measures including an involuntary memory task. In the diary, participants reported more involuntary memories from the imagery condition than from the verbal condition, and more involuntary memories from their own photos compared to the other photos. A more mixed pattern of findings was found across other tasks in the lab. The study indicates that the paradigm can be used as a means to induce positive IMI and that using photos as the basis for generating positive imagery increases the amount of IMI in daily life. Theoretical and potential clinical implications are discussed.