Strategic retrieval in a reality monitoring task.

Strategic recollection refers to control processes that allow the retrieval of information that is relevant for a specific situation. These processes can be studied in memory exclusion tasks, which require the retrieval of particular kinds of episodic information. In the current study, we investigated strategic recollection in reality monitoring by event-related potentials (ERPs). Participants studied object words, followed by a picture of the denoted object (perceive condition) or followed by the instruction to imagine such a picture (imagine condition). At test, subjects had to identify words of one study condition and to reject words of the second study condition together with newly presented items. Data analysis showed that object names were better identified when items of the perceive condition were targeted. In this test condition, a left parietal old/new effect (the ERP correlate of recollection) was observed only in response to targets. In contrast, both targets and nontargets elicited this old/new effect when items of the imagine condition were targeted. The magnitude of the left parietal old/new effect to nontargets in this condition (but no other left parietal old/new effect) correlated positively with the discrimination indices of both test conditions. In addition, ERPs to targets and nontargets differed at right frontal electrode sites at longer latencies (1500-1800 ms), with more positive ERPs for targets. Findings indicate that subjects retrieved nontarget information in the more difficult task condition, while they relied on target information alone in the less difficult task. This kind of strategic retrieval was not mirrored in other old/new effects. The correlation between the left parietal old/new effect for nontargets in the imagined item target condition and the discrimination indices of both conditions may indicate that the ease of nontarget retrieval, rather than the difficulty of target retrieval, increases the likelihood that nontarget information is actually retrieved.