Scanning temporally structured lists: Evidence for dual retrieval processes.

Ss were presented with lists of memory items containing one temporal pause. After each list, Ss were asked to classify a test item as positive or negative based on the memory information. In Experiments I and II, the test item was to be classified as positive if it occurred in the memory set at all, and mean reaction times for the decision were longer than for a no-pause control. In Experiment III, a positive response was required provided that the test item was in a relevant portion of the list as defined by a postlist cue. Reaction times were longer and showed a somewhat different pattern than for a no-pause control. An interpretation was offered based on the hypothetical existence of two simultaneously executed serial scans, one "exhaustive" and the other "self-terminating," as defined by S. Sternberg.