Event-related potentials indicate that reality monitoring differs from external source monitoring

This experiment investigated differences in event-related potentials (ERPs) observed in 2 types of source monitoring decisions. Participants discriminated between self-generated, heard, and new words (reality monitoring) in one condition; in another they discriminated between words heard in a male or female voice and new items (external source monitoring). The data support the source monitoring framework, which argues that reality monitoring discriminations differ from external source monitoring discriminations. Analysis revealed better overall source accuracy during reality monitoring than during external source monitoring. In the external source monitoring task, an early old-new ERP difference was observed at parietal electrodes followed by frontal old-new effect that persisted longer, replicating previous ERP results. However, early ERP amplitude differences between sources were observed at parietal electrode sites during reality monitoring, suggesting that self-generated items activate more differentiated information during remembering. Furthermore, there were no frontal old-new ERP differences during reality monitoring, suggesting that different decision processes are used in these types of source monitoring decisions.