Working memory limitations constrain visual episodic long-term memory at both specific and gist levels of representation.

Limitations in one's capacity to encode information in working memory (WM) constrain later access to that information in long-term memory (LTM). The present study examined whether these WM constraints on episodic LTM are limited to specific representations of past episodes or also extend to gist representations. Across three experiments, young adult participants (n = 40 per experiment) studied objects in set sizes of two or six items, either sequentially (Experiments 1a and 1b) or simultaneously (Experiment 2). They then completed old/new recognition tests immediately after each sequence (WM tests). After a long study phase, participants completed LTM conjoint recognition tests, featuring old but untested items from the WM phase, lures that were similar to studied items at gist but not specific levels of representation, and new items unrelated to studied items at both specific and gist levels of representation. Results showed that LTM estimates of specific and gist memory representations from a multinomial-processing-tree model were reduced for items encoded under supra-capacity set sizes (six items) relative to within-capacity set sizes (two items). These results suggest that WM encoding capacity limitations constrain episodic LTM at both specific and gist levels of representation, at least for visual objects. The ability to retrieve from LTM each type of representation for a visual item is contingent on the degree to which the item could be encoded in WM.

Why does visual working memory ability improve with age: More objects, more feature detail, or both? A registered report.

We investigated how visual working memory (WM) develops with age across the early elementary school period (6-7 years), early adolescence (11-13 years), and early adulthood (18-25 years). The work focuses on changes in two parameters: the number of objects retained at least in part, and the amount of feature-detail remembered for such objects. Some evidence suggests that, while infants can remember up to three objects, much like adults, young children only remember around two objects. This curious, nonmonotonic trajectory might be explained by differences in the level of feature-detail required for successful performance in infant versus child/adult memory paradigms. Here, we examined if changes in one of two parameters (the number of objects, and the amount of detail retained for each object) or both of them together can explain the development of visual WM ability as children grow older. To test it, we varied the amount of feature-detail participants need to retain. In the baseline condition, participants saw an array of objects and simply were to indicate whether an object was present in a probed location or not. This phase begun with a titration procedure to adjust each individual's array size to yield about 80% correct. In other conditions, we tested memory of not only location but also additional features of the objects (color, and sometimes also orientation). Our results suggest that capacity growth across ages is expressed by both improved location-memory (whether there was an object in a location) and feature completeness of object representations.

Children's long-term retention is directly constrained by their working memory capacity limitations.

We explored the causal role of individual and age-related differences in working memory (WM) capacity in long-term memory (LTM) retrieval. Our sample of 160 participants included 120 children (6-13-years old) and 40 young adults (18-24 years). Participants performed a WM task with images of unique everyday items, presented at varying set sizes. Subsequently, we tested participants' LTM for items from the WM task. Using these measures, we estimated the ratio at which items successfully held in WM were recognized in LTM. While WM and LTM generally improved with age, the ability to transfer information from WM to LTM appeared consistent between age groups. Moreover, individual differences in WM capacity appeared to predict LTM encoding. Overall, these results suggested that LTM performance was constrained by experimental, individual, and age-related WM limitations. We discuss the theoretical and practical implications of this WM-to-LTM bottleneck.

Age-related differences in adults' ability to follow spoken instructions.

A growing body of research illustrates that working memory capacity is a crucial limiting factor in our ability to follow spoken instructions. Despite the ubiquitous nature of instruction following throughout the lifespan, how the natural ageing process affects the ability to do so is not yet fully understood. In this study, we investigated the consequences of action at encoding and recall on the ability to follow spoken instructions. Younger (< 30 y/o) and older (> 65 y/o) adults recalled sequences of spoken action commands under presentation and recall conditions that either did or did not involve their physical performance. Both groups showed an enacted-recall advantage, with superior recall by physical performance than oral repetition. When both encoding and recall were purely verbal, older adults' recall accuracy was comparable to that of their younger counterparts. When action was involved at either encoding or recall, however, the difference in performance between the two age groups became pronounced: enactment-based encoding significantly improved younger adults' ability to follow spoken instructions; there was no such advantage for older adults. These data show that spatial-motoric representations disproportionately benefit younger adults' memory performance. We discuss the practical implications of these findings in the context of lifelong learning.

Cognitive aging and verbal labeling in continuous visual memory.

The decline of working memory (WM) is a common feature of general cognitive decline, and visual and verbal WM capacity appear to decline at different rates with age. Visual material may be remembered via verbal codes or visual traces, or both. Souza and Skóra, Cognition, 166, 277-297 (2017) found that labeling boosted memory in younger adults by activating categorical visual long-term memory (LTM) knowledge. Here, we replicated this and tested whether it held in healthy older adults. We compared performance in silence, under instructed overt labeling (participants were asked to say color names out loud), and articulatory suppression (repeating irrelevant syllables to prevent labeling) in the delayed estimation paradigm. Overt labeling improved memory performance in both age groups. However, comparing the effect of overt labeling and suppression on the number of coarse, categorical representations in the two age groups suggested that older adults used verbal labels subvocally more than younger adults, when performing the task in silence. Older adults also appeared to benefit from labels differently than younger adults. In younger adults labeling appeared to improve visual, continuous memory, suggesting that labels activated visual LTM representations. However, for older adults, labels did not appear to enhance visual, continuous representations, but instead boosted memory via additional verbal (categorical) memory traces. These results challenged the assumption that visual memory paradigms measure the same cognitive ability in younger and older adults, and highlighted the importance of controlling differences in age-related strategic preferences in visual memory tasks.

A lifespan study of the confidence-accuracy relation in working memory and episodic long-term memory.

The relation between an individual's memory accuracy and reported confidence in their memories can indicate self-awareness of memory strengths and weaknesses. We provide a lifespan perspective on this confidence-accuracy relation, based on two previously published experiments with 320 participants, including children aged 6-13, young adults aged 18-27, and older adults aged 65-77, across tests of working memory (WM) and long-term memory (LTM). Participants studied visual items in arrays of varying set sizes and completed item recognition tests featuring 6-point confidence ratings either immediately after studying each array (WM tests) or following a long period of study events (LTM tests). Confidence-accuracy characteristic analyses showed that accuracy improved with increasing confidence for all age groups and in both WM and LTM tests. These findings reflect a universal ability across the lifespan to use awareness of the strengths and limitations of one's memories to adjust reported confidence. Despite this age invariance in the confidence-accuracy relation, however, young children were more prone to high-confidence memory errors than other groups in tests of WM, whereas older adults were more susceptible to high-confidence false alarms in tests of LTM. Thus, although participants of all ages can assess when their memories are weaker or stronger, individuals with generally weaker memories are less adept at this confidence-accuracy calibration. Findings also speak to potential different sources of high-confidence memory errors for young children and older adults, relative to young adults. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Working Memory Constrains Long-Term Memory in Children and Adults: Memory of Objects and Bindings.

We explored how individual and age-related differences in working memory (WM) capacity affected subsequent long-term memory (LTM) retrieval. Unlike past studies, we tested WM and LTM not only for items, but also for item-color bindings. Our sample included 82 elementary school children and 42 young adults. The participants performed a WM task with images of unique everyday items presented sequentially at varying set sizes in different colors. Later, we tested LTM for items and item-color bindings from the WM task. The WM load during encoding constrained LTM, and participants with a higher WM capacity retrieved more items in the LTM test. Even when accounting for young children's poor item memory by considering only the items that they did remember, they exhibited an exacerbated difficulty with remembering item-color bindings in WM. Their LTM binding performance, however, as a proportion of remembered objects, was comparable to that of older children and adults. The WM binding performance was better during sub-span encoding loads, but with no clear transfer of this benefit to LTM. Overall, LTM item memory performance was constrained by individual and age-related WM limitations, but with mixed consequences for binding. We discuss the theoretical, practical, and developmental implications of this WM-to-LTM bottleneck.

The role of domain-general attention and domain-specific processing in working memory in algebraic performance: An experimental approach.

We investigated the role of working memory in symbolic and spatial algebra and related tasks across five experiments. Each experiment combined a processing task (expression evaluation, arithmetic, coordinate plane, geometry, or mental rotation) with verbal and spatial memory loads in a dual-task design. Spatial memory was compromised in the presence of more difficult processing tasks, and verbal memory was only compromised in the presence of algebraic tasks. The latter was related to the demands of retaining quantities associated with variables in verbal memory. We suggest that both verbal and spatial working memory retention engage domain-general attention, but that their maintenance mechanisms differ. Verbal memory has attention-based and rehearsal-based mechanisms, and thus sustaining verbal information over a short period is less attention-demanding than holding spatial information. We suggest that effects of a memory load on processing (e.g., x = 6) depend on whether use of maintenance strategies are possible for the specific memory load while carrying out processing. In all, our results indicate that algebraic tasks use domain-general attention and include verbal processing of algebraic variables (i.e., information conveyed in x, y). We discuss the implications for algebra learning and working memory theories. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The proportion of working memory items recoverable from long-term memory remains fixed despite adult aging.

We explored whether long-term memory (LTM) retrieval is constrained by working memory (WM) limitations, in 80 younger and 80 older adults. Participants performed a WM task with images of unique everyday items, presented at varying set sizes. Subsequently, we tested participants' LTM for items from the WM task and examined the ratio of LTM/WM retention. While older adults' WM and LTM were generally poorer than that of younger adults, their LTM deficit was no greater than what was predicted from their WM performance. The ability to encode WM information into LTM appeared immune to age-related cognitive decline. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The development of metacognitive accuracy in working memory across childhood.

Growth in working memory capacity, the number of items kept active in mind, is thought to be an important aspect of childhood cognitive development. Here, we focused on participants' awareness of the contents of their working memory, or meta-working memory, which seems important because people can put cognitive abilities to best use only if they are aware of their limitations. In two experiments on the development of meta-working memory in children between 6 and 13 years old and adults, participants were to remember arrays of colored squares and to indicate if a probe item was in the array. On many trials, before the probe recognition test, they reported a metajudgment, how many items they thought they remembered. We compared meta-working memory judgments to actual performance and looked for associations between these measures on individual and trial-by-trial levels. Despite much lower working memory capacity in younger children there was little change in meta-working memory judgments across age groups. Consequently, younger participants were much less realistic in their metajudgments concerning their working memory capability. Higher cognitive capacity was associated with more accurate meta-working memory judgments within an age group. Trial-by-trial tuning of metajudgments was evident only in young adults and then only for small array set sizes. In sum, meta-working memory ability is a sophisticated skill that develops with age and may be an integral aspect of the development of working memory across the school years. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Working memory limits severely constrain long-term retention.

There has been considerable controversy in recent years as to whether information held in working memory (WM) is rapidly forgotten or automatically transferred to long-term memory (LTM). Although visual WM capacity is very limited, we appear able to store a virtually infinite amount of information in visual LTM. Still, LTM retrieval often fails. Some view visual WM as a mental sketchpad that is wiped clean when new information enters, but not a consistent precursor of LTM. Others view the WM and LTM systems as inherently linked. Distinguishing between these possibilities has been difficult, as attempts to directly manipulate the active holding of information in visual WM has typically introduced various confounds. Here, we capitalized on the WM system's capacity limitation to control the likelihood that visual information was actively held in WM. Our young-adult participants (N = 103) performed a WM task with unique everyday items, presented in groups of two, four, six, or eight items. Presentation time was adjusted according to the number of items. Subsequently, we tested participants' LTM for items from the WM task. LTM was better for items presented originally within smaller WM set sizes, indicating that WM limitations contribute to subsequent LTM failures, and that holding items in WM enhances LTM encoding. Our results suggest that a limit in WM capacity contributes to an LTM encoding bottleneck for trial-unique familiar objects, with a relatively large effect size.

Exploring the influence of temporal factors on age differences in working memory dual task costs.

Working memory is defined by many as the system that allows us to simultaneously store information over brief time periods while engaging in other information processing activities. In a previous study (Rhodes, Jaroslawska et al. (2019) Journal of Experimental Psychology: General, 148, 1204-1227.) we found that retention of serially presented letters was disrupted by the introduction of an arithmetic processing task during a 10 second delay period. Importantly, the magnitude of this dual task disruption increased with age from 18 to 81. The demands of each task were adjusted prior to dual task so that age differences did not reflect baseline differences in single task performance. Motivated by these findings, theories of working memory, and additional analyses of processing reaction times from this previous experiment, we report two experiments, using the same tasks and adjustment procedure, attempting to modulate the magnitude of age differences in dual task effects via manipulations focused on time for encoding to-be-remembered material. Providing a delay prior to processing activities, to facilitate switching between the two tasks, did not modulate age differences. Neither did separating the to-be-remembered material temporally, to allow for the creation of more distinct representations. These findings provide two replications of our initial finding and suggest that age differences in working memory dual tasking are not due to limitations in the speed of encoding. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Strategy mediation in working memory training in younger and older adults.

Working memory (WM) training with the N-Back task has been argued to improve cognitive capacity and general cognitive abilities (the Capacity Hypothesis of training), although several studies have shown little or no evidence for such improvements beyond tasks that are very similar to the trained task. Laine et al. demonstrated that instructing young adult participants to use a specific visualisation strategy for N-back training resulted in clear, generalised benefits from only 30 min of training (Strategy Mediation Hypothesis of training). Here, we report a systematic replication and extension of the Laine et al. study, by administering 60 younger and 60 older participants a set of WM tasks before and after a 30-min N-back training session. Half the participants were instructed to use a visualisation strategy, the others received no instruction. The pre-post test battery encompassed a criterion task (digit N-back), two untrained tasks N-back tasks (letters and colours), and three structurally different WM tasks. The instructed visualisation strategy significantly boosted at least some measures of N-back performance in participants of both age groups, although the strategy generally appeared more difficult to implement and less beneficial for older adults. However, the strategy did not improve performance on structurally different WM tasks. We also found significant associations between N-back performance and the type and level of detail of self-generated strategies in the uninstructed participants, as well as age group differences in reported strategy types. WM performance appeared to partly reflect the application of strategies, and Strategy Mediation should be considered to understand the mechanisms of WM training. Claims of efficient training should demonstrate useful improvement beyond task-specific strategies.

How Do Scientific Views Change? Notes From an Extended Adversarial Collaboration.

There are few examples of an extended adversarial collaboration, in which investigators committed to different theoretical views collaborate to test opposing predictions. Whereas previous adversarial collaborations have produced single research articles, here, we share our experience in programmatic, extended adversarial collaboration involving three laboratories in different countries with different theoretical views regarding working memory, the limited information retained in mind, serving ongoing thought and action. We have focused on short-term memory retention of items (letters) during a distracting task (arithmetic), and effects of aging on these tasks. Over several years, we have conducted and published joint research with preregistered predictions, methods, and analysis plans, with replication of each study across two laboratories concurrently. We argue that, although an adversarial collaboration will not usually induce senior researchers to abandon favored theoretical views and adopt opposing views, it will necessitate varieties of their views that are more similar to one another, in that they must account for a growing, common corpus of evidence. This approach promotes understanding of others' views and presents to the field research findings accepted as valid by researchers with opposing interpretations. We illustrate this process with our own research experiences and make recommendations applicable to diverse scientific areas.

Aging and feature-binding in visual working memory: The role of verbal rehearsal.

Age-related decline in ability to bind and remember conjunctions of features has been proposed as an explanation for the pronounced decline of visual working memory (WM) in healthy aging. However, evidence that older adults exhibit greater visual feature-binding deficits than younger adults has been mixed. Binding deficits in older adults are often observed using paradigms with easy-to-label features. Labeling and rehearsing single features may result in apparent binding deficits if older adults rely on comparatively intact verbal memory to compensate for declining visual WM. This strategy would be more useful for single features (e.g., "red"), than for conjunctions of features (e.g., "red triangle"), which are more cumbersome to rehearse, and thus visual feature-binding paradigms that do not prevent verbal strategies may unintentionally measure verbal load differences. Across 3 experiments (total N = 150), we investigated the role of verbal rehearsal by manipulating ease of stimulus labeling for visually presented single features and conjunctions of 2 features. Overall, visual memory for difficult-to-label, noncategorical, visual information appeared especially limited for older adults, likely because it impedes engagement of other systems, such as verbal WM or long-term memory. Therefore, comparing younger- and older-adult task performance may not straightforwardly reveal age-related visual WM decline, but instead reflect applications of different strategies that tap different cognitive mechanisms. We discuss implications for the feature-binding literature and the wider visual WM literature. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Tool use modulates early stages of visuo-tactile integration in far space: Evidence from event-related potentials.

The neural representation of multisensory space near the body is modulated by the active use of long tools in non-human primates. Here, we investigated whether the electrophysiological correlates of visuo-tactile integration in near and far space were modulated by active tool use in healthy humans. Participants responded to a tactile target delivered to one hand while an irrelevant visual stimulus was presented ipsilaterally in near or far space. This crossmodal task was performed after the use of either short or long tools. Crucially, the P100 components elicited by visuo-tactile stimuli was enhanced on far as compared to near space trials after the use of long tools, while no such difference was present after short tool use. Thus, we found increased neural responses in brain areas encoding tactile stimuli to the body when visual stimuli were presented close to the tip of the tool after long tool use. This increased visuo-tactile integration on far space trials following the use of long tools might indicate a transient remapping of multisensory space. We speculate that performing voluntary actions with long tools strengthens the representation of sensory information arising within portions of space (i.e. the hand and the tip of the tool) that are most functionally relevant to one's behavioural goals.