There is a theoretical disagreement in the working memory literature, with some proposing that the storage and processing of information rely on distinct parts of the cognitive system and others who posit that they rely, to some extent, on a shared attentional capacity. This debate is mirrored in the literature on working memory and aging, where there have been mixed findings on the ability of older adults to perform simultaneous storage and processing tasks. We assess the overlap between storage and processing and how this changes with age using a procedure in which both tasks have been carefully adjusted to produce comparable levels of single-task performance across a sample (N = 164) of participants aged 18-81. By manipulating incentives to perform one task over the other, this procedure was also capable of disentangling concurrence costs (single- vs. dual-task performance) from prioritization costs (relative payoffs for storage vs. processing performance) in a theoretically meaningful manner. The study revealed a large general cost to serial letter recall performance associated with concurrent performance of an arithmetic verification processing task, a concurrence cost that increased with age. For the processing task, there was no such general concurrence cost. Rather, there was a prioritization effect in dual-task performance for both tasks, irrespective of age, in which performance levels depended on the relative emphasis assigned to memory versus processing. This prioritization effect was large, albeit with a large residual in performance. The findings place important constraints on both working memory theory and our understanding of how working memory changes across the adult lifespan. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
One of the most evidential behavioral results for two memory processes comes from Gardiner and Java (Memory & Cognition, 18, 23–30 1990). Participants provided more “remember” than “know” responses for old words but more know than remember responses for old nonwords. Moreover, there was no effect of word/nonword status for new items. The combination of a crossover interaction for old items with an invariance for new items provides strong evidence for two distinct processes while ruling out criteria or bias explanations. Here, we report a modern replication of this study. In three experiments, (Experiments 1, 2, and 4) with larger numbers of items and participants, we were unable to replicate the crossover. Instead, our data are more consistent with a single-process account. In a fourth experiment (Experiment 3), we were able to replicate Gardiner and Java’s baseline results with a sure–unsure paradigm supporting a single-process explanation. It seems that Gardiner and Java’s remarkable crossover result is not replicable.
It has been suggested that an age-related decrease in the ability to bind and retain conjunctions of features may account for some of the pronounced decline of visual working memory (VWM) across the adult life span. So far the evidence for this proposal has been mixed with some suggesting a specific deficit in binding to location, while the retention of surface feature conjunctions (e.g., color-shape) appears to remain largely intact. The present experiments follow up on the results of an earlier study, which found that older adults were specifically poor at detecting conjunction changes when they were mixed with trials containing changes to individual features, relative to when these trials were blocked (Cowan, Naveh-Benjamin, Kilb, & Saults, 2006). Using stimuli defined by conjunctions of color and shape (Experiment 1), and color and location (Experiment 2) we find no evidence that older adults are less accurate at detecting binding changes when trial types are mixed. Further, analysis of estimates of discriminability provides substantial-to-strong evidence against this suggestion. We discuss these findings in relation to previous studies addressing the same question and suggest that much of the evidence for specific age-related VWM binding deficits is not as strong as it first appears. (PsycINFO Database Record