The irrelevant speech effect in backward recall is modulated by foreknowledge of recall direction and response modality.

Abstract

In backward immediate serial recall, participants recall lists of items immediately after their presentation by beginning with the last presented item and ending with the first presented one. Despite the similarities with forward recall in which participants recall the items from the first to the last presented, benchmark memory phenomena reliably found in forward recall are not constantly observed in backward recall. Here, we proposed a new framework called the encoding-retrieval matching (ERM) hypothesis to account for backward recall. The ERM retains the main features of the visuospatial hypothesis and the item-order trade-off hypothesis, the two dominant accounts of backward recall. According to the ERM, output modality and foreknowledge of recall direction influence the availability of visuospatial representations and the weight devoted to item and order processing. We tested the ERM with irrelevant speech, a well-known working memory factor disrupting forward recall. In two experiments, we manipulated recall direction (forward vs. backward), irrelevant speech (control vs. irrelevant speech), and response modality (manual vs. oral). As predicted by the ERM, when recall direction was unpredictable in Experiment 1, the magnitude of the irrelevant speech effect was larger in backward manual recall than in backward oral recall. In Experiment 2, recall direction was predictable. As predicted by the ERM, in backward recall, the irrelevant speech effect was reduced with a manual response and absent with an oral response. We concluded that ERM effectively accounts for the complex interplay between response modality, foreknowledge of recall direction, and benchmark memory effects in backward recall.