Directed forgetting involves the targeted removal of memory representations. Previous research has indicated that directed forgetting in working memory reduces the amount of proactive interference for to-be-forgotten memoranda relative to to-be-remembered memoranda. However, it is unknown how directed forgetting within working memory compares to an encode-only condition, in which items are encoded but do not receive a forget cue nor a remember instruction. Here, younger adults (N = 43) performed a working memory directed forgetting task with encode-only trials and a recent probes manipulation to induce proactive interference. Results indicated that (1) proactive interference for encoded-only items did not significantly differ from proactive interference for to-be-remembered items, and (2) proactive interference for to-be-forgotten items was significantly lower than that for both the remember and encode-only conditions. Thus, the present research provides support for the theories that directed forgetting instructions result in differential weakening of targeted memory representations in working memory, and that forget instructions promote goal-directed removal of memory representations. Forget instructions do not simply curtail processing after encoding. This research adds to the understanding of the removal of information from working memory and to the consequences and mechanistic processes of directed forgetting within working memory.
