An electrophysiological dissociation of retrieval mode and retrieval orientation.

The relationship between two classes of retrieval process-retrieval orientation and retrieval mode-was investigated by recording event-related potentials (ERPs) during the period in which participants were preparing to retrieve information from memory. Participants were cued on a trial-by-trial basis to complete either a semantic retrieval task or one of two episodic retrieval tasks (remember spatial location or remember encoding task). ERPs were recorded time-locked to the cues indicating which task to complete. There were commonalities between the ways in which ERPs evoked by the two episodic retrieval cues diverged from those evoked by the semantic cue. These shared differences are a likely correlate of processes related to retrieval mode. Critically, there were also reliable differences between the ERPs evoked by the two episodic cues. This novel finding is consistent with the view that participants adopted task-specific retrieval sets-retrieval orientations-which varied according to the kinds of episodic information that were to be retrieved.