The relative roles of input and output mechanisms in directed forgetting

When Ss are presented a first set of items (Set A) followed by a second set (Set B), a postinput cue to recall only Set B results in better recall of Set B than does a cue to recall Set B then Set A; to a lesser extent, the same result holds for Set A. Such "Only" effects (Epstein, 1970) have typically been attributed to selective search processes at the time of recall. In the free-recall experiment reported here, cues to remember all, only two, or none of the items in each of eight successive four-word blocks were presented either before or after a 3-sec rehearsal period. Even though the search set at output was constant (16 to-be-recalled words), there was an Only effect for blocks followed by selective (postcue) rehearsal, whereas nonselective (precue) rehearsal produced no such effect. More striking than that result was the incredible ability of Ss, whatever the condition, to differentiate to-be-remembered and to-be-forgotten items. Set differentiation during input appears much more important as a mechanism of directed forgetting than either selective search or selective rehearsal.