List-method directed forgetting: Evidence for the reset-of-encoding hypothesis employing item-recognition testing

In list-method directed forgetting (LMDF), people are cued to forget a previously studied item list (List 1) and to learn a new list of items (List 2) instead. Such cuing typically enhances memory for the List 2 items, in both recall and (sometimes) item-recognition testing. It has recently been hypothesized that the enhancement effect for List 2 items (partly) reflects the result of a reset-of-encoding process. The proposal is that encoding efficacy decreases with an increase in study material, but the forget cue can reset the encoding process to make the encoding of early List 2 items as effective as the encoding of early List 1 items. An experiment is reported that examined the reset-of-encoding hypothesis with item-recognition testing, examining influences of items' serial learning position on the effects of the forget cue. Item-recognition tests were conducted separately for the two lists. Consistent with the reset-of-encoding hypothesis, the results showed strong enhancement effects for early List 2 items, but hardly any enhancement effects for middle and late List 2 items. Like in previous item-recognition studies, no cuing effects were found for List 1 items. The results support two-mechanism accounts of LMDF, which assume a critical role for a reset-of-encoding process for List 2 enhancement.