Task-switching and memory retrieval processing: electrophysiological evidence.

Participants attempted to retrieve phonological or imagery-based information under conditions where either the two kinds of retrieval were required in separate blocks, or where frequent switches between retrieval tasks were required within blocks. Electrophysiological indices of processes engaged in pursuit of accurate memory judgments, elicited by contrasting ERPs evoked by correctly identified new test items, differed according to retrieval task only when the tasks were completed in separate blocks. The principal conclusion suggested by these findings is that the requirement to alternate frequently between the two retrieval tasks attenuated the engagement of task-specific processes that form part of a retrieval attempt.