Electromyographic evidence for response conflict in the exclude recognition task.

How do memory retrieval processes lead to overt responses in strategic recognition tasks (responding "old" to one class of familiar stimulus and "new" to another)? Many current theories of memory retrieval ignore the response requirements in such memory tasks, instead modeling them using memory processes (e.g., familiarity and recollection) alone (see Yonelinas, 2002). We argue that strategic recognition involves conflict in response processing similar to canonical conflict tasks (e.g., the Stroop task). The parallel task set (PTS) model (Seymour, 2001) accounts for performance in strategic recognition tasks (e.g., the exclude recognition task) by suggesting that motor response conflict occurs when one responds "new" to familiar stimuli. We tested this prediction using surface electromyography, a measure incontrovertibly related to motor execution. Overall, results are consistent with the PTS model's assumption that recognition, motor, and control processes interact in strategic retrieval tasks. The implications of these data for models of memory retrieval and response conflict are discussed.