Reality monitoring performance and the role of visual imagery in visual hallucinations

•People with hallucinations may have “inner-outer confusion”.•Visual imagery may contribute to this “confusion” in visual hallucinations (VH).•Visual imagery vividness and frequency were greater in people with more VH.•People with more VH confused internal experience with true visual perception.

BackgroundAuditory Hallucinations may arise from people confusing their own inner speech with external spoken speech. People with visual hallucinations (VH) may similarly confuse vivid mental imagery with external events. This paper reports two experiments exploring confusion between internal and external visual material.MethodExperiment 1 examined reality monitoring in people with psychosis; those with visual hallucinations (n = 16) and those without (n = 15). Experiment 2 used two non-clinical groups of people with high or low predisposition to VH (HVH, n = 26, LVH, n = 21). All participants completed the same reality monitoring task. Participants in Experiment 2 also completed measures of imagery.ResultsPsychosis patients with VH demonstrated biased reality monitoring, where they misremembered items that had been presented as words as having been presented as pictures. Patients without VH did not show this bias. In Experiment 2, the HVH group demonstrated the same bias in reality monitoring that psychosis patients with VH had shown. The LVH group did not show this bias. In addition, the HVH group reported more vivid imagery and particularly more negative imagery.ConclusionsBoth studies found that people with visual hallucinations or prone-ness to such experiences confused their inner visual experiences with external images. Vivid imagery was also related to proneness to VH. Hence, vivid imagery and reality monitoring confusion could be contributory factors to understanding VH.