Informative and uninformative prestimulus cues at encoding benefit familiarity and source memory.

Previous research has shown that neural activity elicited by informative prestimulus cues during encoding differ with respect to subsequent memory outcomes. These findings indicate prestimulus cues create a "brain state" associated with subsequent memory that, potentially, also has downstream effects benefitting processes associated with successful encoding and subsequent memory performance. However, previous studies have not included the conditions necessary to appropriately test this latter assumption. The present study examines how informative and uninformative prestimulus encoding cues affect memory accuracy for upcoming stimuli compared to a no cue condition. At encoding, participants made one of two semantic judgments on words preceded by an informative prestimulus cue that identified the upcoming semantic judgment, an uninformative prestimulus cue that signalled an upcoming trial but no information about the semantic judgment, or no cue. Dual process estimates of familiarity, but not recollection, demonstrated a graded pattern with the informativeness of the prestimulus cues (i.e., informative > uninformative > no cues). Moreover, both informative and uninformative prestimulus cues enhanced subsequent source memory accuracy for the encoding task compared to the no cue condition. These findings suggest that prestimulus cues can strengthen the processes that support successful memory encoding and benefit subsequent familiarity and source memory.