The ERP correlates of target checking are dependent upon the defining features of the prospective memory cues

In some contexts, prospective memory (PM) is thought to be dependent upon strategic monitoring of the environment for relevant cues. Behavioral data reveal that strategic monitoring is associated with slowing of response time for ongoing activity trials when a prospective component is added to the task, and functional imaging data reveal that monitoring is associated with recruitment of the anterior prefrontal cortex and other cortical structures. In the current study, event-related brain potentials (ERPs) were used to examine the neural correlates of target checking, one process underlying strategic monitoring. Consistent with previous research the behavioral data revealed a Stimulus Specific Interference Effect, wherein slowing of response time varied depending upon whether PM cues were words or nonwords. The ERP data also revealed that the neural correlates of target checking were sensitive to the defining features of the PM cues (i.e., were a word or nonword). When PM cues were words, the effect of target checking was associated with variation in ERP amplitude beginning around 100ms after stimulus onset. In contrast, when PM cues were nonwords, the effect of target checking on the ERPs did not emerge until around 200ms after stimulus onset. These data provide support for the multi-process view of PM by demonstrating that the pattern of neural recruitment related to target checking is sensitive to the defining characteristics of the PM cues.