Abstract

Research has suggested that working memory (WM) capacity can constrain the transfer of visual information to long-term memory (LTM) and contribute to an encoding bottleneck. To investigate the generalization of the visual bottleneck to verbal information, six experiments were carried out with separate samples of young-adult participants (total N = 516). The likelihood that verbal items (words or nonwords) were actively held in WM was controlled by presenting items in sets of two, four, and six with presentation time adjusted accordingly. In Experiment 1, visual words were presented simultaneously (Experiment 1a) and sequentially (Experiment 1b), and in Experiments 2a and 2b, memory items were visual nonwords respectively presented simultaneously and sequentially. A third set of experiments presented verbal items auditorily: words in Experiment 3a and nonwords in Experiment 3b. Analyses of participants’ performance on WM and subsequent LTM tasks found that both WM and LTM were better for items presented in smaller set sizes in all experiments, where memory items were presented visually. In the auditory modality, WM capacity limitations appeared to impact the immediate, but not later recognition, of both words and nonwords. These intriguing findings provide evidence of a WM-to-LTM bottleneck for visually presented verbal information but suggest that this bottleneck does not generalize to auditory (i.e., heard) information. The WM-to-LTM bottleneck therefore appears modality-dependent.

Knight, E. D.,, Guitard, D., Von Bastian, C. C., & Forsberg, A., (2026) When Words Are Seen but Not Heard: Working Memory Constrains Long-Term Memory for Visually Presented, but Not for

Auditorily Presented, Verbal Information. Journal of Experimental Psychology: Learning, Memory, and Cognition (in press).

Abstract

Working memory allows us to store information in mind over brief time periods while engaging in other informationprocessing activities. As such, this system supports cognitive dual-tasking, that is, remembering information whileperforming a concurrent processing task. Age-related dual-task deficits have been proposed as a critical feature of
lifespan cognitive decline. However, evidence regarding such deficits has been mixed, and knowledge of the conditions
under which such deficits appear remains elusive. Moreover, several studies have suggested that different aspects of
working memory decline at different rates with age and that age-related change is not necessarily linear. We explored
lifespan changes in 539 participants (aged 15–90 years) on several memory, processing, and dual (combined) tasks. We
addressed two research questions: (1) Does the magnitude of dual-task costs change across the lifespan? (2) Do different
measures of memory, processing and dual-tasking, all decline at the same rate with age? We found that younger-young
adults outperformed all other participants on dual-task measures. However, deficits did not appear to increase from the
age of 35 years into older age, suggesting that dual-task ability declined in early adulthood but not thereafter between
midlife and older age. Processing performance appeared to decline linearly and more rapidly with age than memory
performance. Our finding that for some measures, the largest changes occurred in the transition from early to middle
adulthood provides an interesting contrast to the widely held assumption that cognition declines continuously across
the adult lifespan.

Forsberg, A., Belletier, C., Graham, A., Rhodes, S., Barrouillet, P., Camos, V., ... & Logie, R. H. (2026). Different measures of working memory decline at different rates across adult ageing and dual task costs plateau in mid-life. Quarterly Journal of Experimental Psychology, 79(2), 462-479.

Abstract

Working Memory (WM) is the cognitive system that allows the temporary holding of mental representations for use in thought and action. Long-Term Memory (LTM) refers to our ability to remember a potentially unlimited amount of information over longer time periods. Understanding how these two memory systems interact has important implications for theories of cognition, learning, and education. Here, we examined (1) whether a shared perceptual bottleneck accounts for the relation between WM and LTM accuracy, and (2) whether serial position effects in WM are mirrored in LTM. In two experiments, participants studied sequences of objects at varying set sizes and completed old/new recognition tests for some items immediately after encoding (WM tests) and for other items after all WM trials were completed (LTM tests). In Experiment 1 (N = 80), LTM performance was better for items presented in lower rather than higher set-size sequences, indicating that limitations in WM capacity constrain LTM encoding, irrespective of perceptual bottlenecks. In Experiment 2 (N = 120), we observed WM and LTM recency effects, but primacy effects were only present in LTM and not in WM. Thus, serial position effects in WM did not consistently predict the relative rates at which items from different serial positions were preserved in LTM. These results reinforce accounts that view WM and LTM as having at least partially separate mechanisms, shedding light on the nature of these mechanisms.

Forsberg, A., Guitard, D., Greene, N. R., Naveh-Benjamin, M., & Cowan, N. (2025). Differential information transfer and loss between working memory and long-term memory across serial positions. Journal of Experimental Psychology: Learning, Memory, and Cognition, 51(8), 1191.

Abstract

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.

Forsberg, A., Guitard, D., Adams, E. J., Pattanakul, D., & Cowan, N. (2023). Working memory constrains long-term memory in children and adults: memory of objects and bindings. Journal of Intelligence, 11(5), 94.

Abstract

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.

Forsberg, A., Adams, E. J., & Cowan, N. (2023). Why does visual working memory ability improve with age: More objects, more feature detail, or both? A registered report. Developmental Science, 26(2), e13283.

Abstract

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.

Forsberg, A., Guitard, D., Greene, N. R., Naveh-Benjamin, M., & Cowan, N. (2022). The proportion of working memory items recoverable from long-term memory remains fixed despite adult aging. Psychology and Aging.

Abstract

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.

Forsberg, A., Guitard, D., & Cowan, N. (2021). Working memory limits severely constrain long-term retention. Psychonomic Bulletin & Review, 28(2), 537-547.

Abstract

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.

Forsberg, A., Guitard, D., Adams, E. J., Pattanakul, D., & Cowan, N. (2021). Children's long-term retention is directly constrained by their working memory capacity limitations. Developmental Science.

Abstract

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.

Forsberg, A., Blume, C. L., & Cowan, N. (2021). The development of metacognitive accuracy in working memory across childhood. Developmental Psychology.