Valérie Camos

Time constraints and resource sharing in adults' working memory spans.

This article presents a new model that accounts for working memory spans in adults, the time-based resource-sharing model. The model assumes that both components (i.e., processing and maintenance) of the main working memory tasks require attention and that memory traces decay as soon as attention is switched away. Because memory retrievals are constrained by a central bottleneck and thus totally capture attention, it was predicted that the maintenance of the items to be recalled depends on both the number of memory retrievals required by the intervening treatment and the time allowed to perform them. This number of retrievals:time ratio determines the cognitive load of the processing component. The authors show in 7 experiments that working memory spans vary as a function of this cognitive load.

Time and cognitive load in working memory.

According to the time-based resource-sharing model (P. Barrouillet, S. Bernardin, & V. Camos, 2004), the cognitive load a given task involves is a function of the proportion of time during which it captures attention, thus impeding other attention-demanding processes. Accordingly, the present study demonstrates that the disruptive effect on concurrent maintenance of memory retrievals and response selections increases with their duration. Moreover, the effect on recall performance of concurrent activities does not go beyond their duration insofar as the processes are attention demanding. Finally, these effects are not modality specific, as spatial processing was found to disrupt verbal maintenance. These results suggest a sequential and time-based function of working memory in which processing and storage rely on a single and general purpose attentional resource needed to run executive processes devoted to constructing, maintaining, and modifying ephemeral representations.

Working Memory Span Development: A Time-Based Resource-Sharing Model Account.

The time-based resource-sharing model (P. Barrouillet, S. Bernardin, & V. Camos, 2004) assumes that during complex working memory span tasks, attention is frequently and surreptitiously switched from processing to reactivate decaying memory traces before their complete loss. Three experiments involving children from 5 to 14 years of age investigated the role of this reactivation process in developmental differences in working memory spans. Though preschoolers seem to adopt a serial control without any attempt to refresh stored items when engaged in processing, the reactivation process is efficient from age 7 onward and increases in efficiency until late adolescence, underpinning a sizable part of developmental differences.

Working Memory Costs of Task Switching

Although many accounts of task switching emphasize the importance of working memory as a substantial source of the switch cost, there is a lack of evidence demonstrating that task switching actually places additional demands on working memory. The present study addressed this issue by implementing task switching in continuous complex span tasks with strictly controlled time parameters. A series of 4 experiments demonstrate that recall performance decreased as a function of the number of task switches and that the concurrent load of item maintenance had no influence on task switching. These results indicate that task switching induces a cost on working memory functioning. Implications for theories of task switching, working memory, and resource sharing are addressed.

Visual and Spatial Working Memory Are Not That Dissociated After All: A Time-Based Resource-Sharing Account

Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and spatial storage were combined with both visual and spatial on-line processing components in computer-paced working memory span tasks (Experiment 1) and in a selective interference paradigm (Experiment 2). The cognitive load of the processing components was manipulated to investigate its impact on concurrent maintenance for both within-domain and between-domain combinations of processing and storage components. In contrast to both domain- and process-based fractionations of visuo-spatial working memory, the results revealed that recall performance was determined by the cognitive load induced by the processing of items, rather than by the domain to which those items pertained. These findings are interpreted as evidence for a time-based resource-sharing mechanism in visuo-spatial working memory.

Human awareness and uses of odor cues in everyday life: Results from a questionnaire study in children

The Childrens Olfactory Behavior in Everyday Life questionnaire was developed to assess attention to, and uses of, odors in real-life situations, and to evaluate individual variations. The tool comprises 16 items prompting self-reports of active seeking, awareness and affective reactivity to odors of food, people and the environment. Children (102 girls, 113 boys) aged 6–10 years participated in the study. The results revealed that girls were significantly more olfaction-oriented than boys, especially towards the odors of people, self and the environment. An increasing ability of children to describe the odor facets of their perceptual world was found between 6 and 10 years, partly due to ameliorating verbal skills. Finally, owning an “attachment object” was linked to olfactory reactivity to odors, especially in social and affective contexts. Overall, this research contributes to expand our understanding of the behavioral importance of odors in children and its individual variations, and it brings additional arguments against the prevalent concept of functional microsmaty applied to the human species.

Is the influence of working memory capacity on high-level cognition mediated by complexity or resource-dependent elementary processes ?

The aim of this study was to investigate the involvement of working memory (WM) in elementary activities and the nature of the mechanisms mediating the influence of WM capacity on high-level cognition. We demonstrate that even elementary activities such as reading digits, subitizing small arrays of dots, or solving simple additions like 3+1 are sensitive to individual differences in WM capacity. Moreover, we demonstrate that a complex task such as counting large arrays of dots involving these elementary activities as processing steps does not induce WM-related differences beyond what can be predicted from the concatenation of differences elicited by the task’s elementary constituents. In line with the time-based resource-sharing model, these results suggest that the influence of WM capacity on high-level cognition is mediated by the impact of a basic general-purpose resource that affects each atomic step of cognition.

Interference: unique source of forgetting in working memory?

In their opinion article, Lewandowsky, Oberauer and Brown [1] make a strong case against time-based accounts of forgetting in short-term and working memory. We argue, however, that the interference-based account they favor is underspecified, that the time-loss functions predicted by time-based models are misconstrued and that the contradictory findings issued from the time-based resource-sharing (TBRS) model [2] are not properly addressed.

Counting strategies from 5 years to adulthood: Adaptation to structural features

The aim of this study was twofold. First, it evaluated the developmental changes on frequency of use, efficiency, and choice of counting strategies from childhood to adulthood. Second, it determined the adaptation of the counting strategies to the structural features of the task. Participants in seven age groups ranging from 5-year-old to adulthood were asked to count dots in arrays varying on size, arrangement, density and size of the subgroups. The nature of the strategies used and their efficiency, i.e. speed, accuracy and rate of manual pointing, were recorded using the overt behavior technique. The developmental pattern of results for the four main strategies, counting by ones, by ns, addition and multiplication, was in line with Siegler’s overlapping waves model. The structural features affected the use of the strategies since 13 years, except for the multiplication strategy. Finally, intra- and inter-individual variability in strategy showed a monotonous increase with age. Implications for understanding the development of counting skill are discussed.RésuméLe but de cette étude était, tout d’abord, d’évaluer les changements développementaux affectant la fréquence d’utilisation, l’efficacité et le choix des stratégies de comptage de 5 ans à l’âge adulte. Cette étude cherchait également à déterminer le degré d’adaptation de ces stratégies de comptage aux caractéristiques de la tâche. Les participants comptaient des collections de points variant en taille, disposition, densité et taille des sous-groupes. La nature des stratégies ainsi que leur efficacité (vitesse, précision et utilisation du pointage manuel) ont été recueillis à partir des performances faites à haute voix (overt-behavior technique). Le développement des quatre principales stratégies étaient compatibles avec le modèle de Siegler (1996). Les caractéristiques de la tâche affectaient l’utilisation des stratégies, mais seulement à partir de 13 ans. De plus, la variabilité intra- et interindividuelle augmentait continuellement avec l’âge. Ces résultats éclairent d’un jour nouveau l’évolution des activités de comptage.

Coordination process in counting

Counting is an important activity because it gives rise to a whole range of arithmetic activities. Counting objects requires subjects to point at each object and to say the corresponding number-word. Furthermore, to determine the correct cardinal of a set, the two activities of pointing and saying must be synchronized. This perfect correspondence between the two activities is achieved by a coordination process. Using Camos et al.s (2001) paradigm, the present study tested the hypothesis that this coordination process will induce its own cognitive cost and that this cost would decrease with age. Eight-year-old children and adults were asked to say the numberline from 1 to 23, from 61 to 83, and from 111 to 133. They also pointed at objects in arrays that did or did not include distracters. Finally, they counted objects in arrays with or without distracters using the numberline starting at 1, then at 61, and then at 111. In children, as in adults, the simultaneous increase in the attentional demand of the ...