List-method directed forgetting: the forget cue improves both encoding and retrieval of postcue information

In list-method directed forgetting, people are cued to forget a previously studied item list and to learn a new list instead. Such cuing typically leads to forgetting of the first list and to memory enhancement of the second, referred to as list 1 forgetting and list 2 enhancement. In the present study, two experiments are reported that examined influences of items' serial learning position in a list and the two lists' output order on list-method directed forgetting. The results show that list output order influences list 2 enhancement but not list 1 forgetting. The enhancement was higher when list 2 was recalled first than when list 1 was recalled first and, in both cases, was higher for early list 2 items than for middle and late list 2 items. In contrast, the forgetting was equally present for all list 1 items and did not depend on the two lists' output order. The findings suggest that two separate factors can contribute to list 2 enhancement: one (encoding) factor that is restricted to early list 2 items and does not depend on list output order, and another (retrieval) factor that pertains to all list 2 items and varies with the two lists' output order. A new two-mechanism account of directed forgetting is suggested that reconciles previous (encoding or retrieval) views on list 2 enhancement.