Digitally manipulating memory: Effects of doctored videos and imagination in distorting beliefs and memories

In prior research on false autobiographical beliefs and memories, subjects have been asked to imagine fictional events and they have been exposed to false evidence that indicates the fictional events occurred. But what are the relative contributions of imagination and false evidence toward false belief and memory construction? Subjects observed and copied various simple actions, then viewed doctored videos that suggested they had performed extra actions, and they imagined performing some of those and some other actions. Subjects returned two weeks later for a memory test. False evidence or imagination alone was often sufficient to cause belief and memory distortions; the two techniques in combination appeared to have additive or even superadditive effects. The results bear on the mechanisms underlying false beliefs and memories, and we propose legal and clinical applications of these findings.