What is time good for in working memory?

Abstract

Increasing time to process information in working memory (WM) improves performance. Free time given after an item is often assumed to enable maintenance processes to counteract forgetting of this item, suggesting that time has a retroactive benefit. Two other hypotheses – short-term consolidation, and temporal distinctiveness – entail a local effect of time on immediately preceding and following items. Here, we show instead a novel, global and proactive, benefit of time in WM. In three serial-recall experiments (21,25,26 young-adults), we varied the position and duration of the free time within a seven-item list of consonants. Experiment 1 showed that the effect is global and not local. Experiments 2a and 2b showed increased inter-item time only benefited the subsequent items, implying a proactive benefit. This finding rules out maintenance processes, short-term consolidation, and temporal distinctiveness as explanations of the free-time benefit but is consistent with the proposal of a gradually recovering encoding resource.

Sequential study effects of free time and word frequency in long-term memory: A critical test of four theories using a large-scale publicly available dataset

“…These results are consistent with a similar recent finding in a working memory serial recall task (Mizrak & Oberauer, 2021). Mizrak and Oberauer found that if one of the intervals in a list of seven words is longer (2500ms) rather than shorter (500ms), this leads to better memory for all subsequent items, but not for the preceding items.…”

“…Despite the seemingly unlimited capacity of long-term memory (LTM;Brady et al, 2008;Konkle et al, 2010;Standing, 1973), there is a limit on how much information can be added to LTM at any given time. As an example of this limit, consider that both short-term memory (STM) and LTM performance consistently degrades when the "free time" between study items is reduced (Brown et al, 2006;Criss & McClelland, 2006;Malmberg & Nelson, 2003;Mizrak & Oberauer, 2021;Ricker & Hardman, 2017). This limitation could arise through various mechanisms -it could be due to reduced temporal distinctiveness (Brown et al, 2006), due to reduced opportunity for articulatory rehearsal or attentional refreshing (Camos et al, 2009), or due to the interruption of a consolidation process (Ricker & Hardman, 2017).…”

“…One promising area in which to test these theories is at the trial level: 1) what are the effects of free time when it varies either before or after a presentation (also see Mizrak & Oberauer, 2021); and 2) does the size of the free time benefit interact with stimulus difficulty? To test these, we turn to the Penn Electrophysiology of Encoding and Retrieval Study (PEERS) dataset, a highly powered public list-learning free recall dataset that, critically, varies the inter-stimulus-interval (ISI) between words in each list on a trial by trial basis (Figure 1a).…”

Between-item similarity frees up working memory resources through compression: A domain-general property.

“…This way of encoding items naturally creates a primacy gradient whose existence is empirically supported (Oberauer, 2003). The plausibility of the encoding-resource account has recently received support from fine-grained investigations of the beneficial effect of free time in immediate serial recall tasks (Mizrak & Oberauer, 2021). Critically, this model can explain the presence of proactive effects in WM.…”

Semantic overlap protects from interference by restoring encoding mechanisms

“…In delayed free recall tasks in which no words are semantically associated, recall performance decreases over serial position (Murdock, 1962). This decrease in probability of recall may arise from decreases in attention (Sederberg et al, 2006; Azizan & Polich, 2007), and/or a decline in encoding resources (Lohnas et al, 2020; Popov & Reder, 2020; Mizrak & Oberauer, 2021). Consistent with previous research, we find a decrease in probability of recall for late list items that did not semantically overlap with a prior list item.…”