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

Abstract

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.

List-method directed forgetting can be selective: Evidence from the 3-list and the 2-list tasks

“…On the other hand, the finding is in line with results from more recent LMDF work (e.g., Delaney & Sahakyan, 2007;Delaney et al, 2009;Sahakyan, 2004;Zellner & Bäuml, 2006), which shows that the enhancement is not always present in LMDF. Pastötter et al (2012) recently demonstrated that the failure to find the enhancement effect often occurs when, at test, the precue items are recalled first and the postcue items are recalled last, a procedure that was also chosen in the present experiment. The General Discussion section below provides a theoretical explanation of this output order effect and discusses the issue further.…”

“…This has recently been documented in a meta-analysis and has been shown experimentally by varying list output order at test (Pastötter et al, 2012). Enhancement of the postcue items in response to the forget cue has often been attributed to reduced interference of the precue items at test (e.g., Geiselman et al, 1983;Sahakyan & Kelley, 2002).…”

“…Recent work on LMDF has shown that cuing participants to forget a previously studied item list leads to forgetting of all the items on this list, impairing recall of the single items about equally (Pastötter & Bäuml, 2010a;Pastötter et al, 2012;Sahakyan & Foster, 2009). While such general forgetting of all the precue information appears adaptive if all the precue information has been designated as unimportant, such forgetting would be less advantageous if, before the forget cue was provided, both relevant and irrelevant information had been encoded and participants, in response to the forget cue, forgot all of the (relevant and irrelevant) precue information.…”

“…Finally, the context-change account claims that the forget cue induces an internal context change that, at test, impairs recall of the precue items due to a mismatch between the context at encoding and the context at retrieval and, due to the reduced interference from the precue items, improves recall of the postcue items (Sahakyan & Kelley, 2002). As an alternative to one-mechanism accounts of LMDF, two-mechanism accounts also have recently been suggested, assuming that the forgetting of the precue items is caused by inhibition or context change, whereas the enhancement of the postcue items (partly) reflects improved encoding (Pastötter, Kliegl, & Bäuml, 2012;Sahakyan & Delaney, 2003).…”

Retrieval practice can eliminate list method directed forgetting

“…These results replicate the findings of many recent studies, in which no list 2 enhancement arose when at test list 1 was recalled first and list 2 was recalled second (e.g., Delaney & Sahakyan, 2007;Delaney, Nghiem, & Waldum, 2009;Pastötter & Bäuml, 2010;Zellner & Bäuml, 2006), a procedure that was also chosen in the present experiment. Indeed, conducting a meta-analysis on the influence of list output order on LMDF, Pastötter, Kliegl, and Bäuml (2012) recently showed that the forget cue induces facilitation for list 2 items mainly when list 2 is tested first and shows hardly any facilitatory effect when list 2 is tested last. The present finding of no list 2 enhancement thus very likely arose due to chosen list output order.…”