Cognitive mechanisms underlying free recall in episodic memory performance across the lifespan: testing the control/representation model.

Episodic memory (EM) develops up to early adulthood, and declines in aging, following an inverted U-shaped profile. This study assessed the contribution of both Control (processes enabling adaptive and flexible behaviour in line with current goals) and Representation (crystallized schemas involved in memory and general knowledge) as factors likely to underlie this pattern of change. We hypothesized that these two cognitive resources are differentially involved in EM performance across development and aging. Participants from 8 to 80 years were administered a free-recall task and tests measuring control and representation. Results show that EM and control scores follow an inverted U-shaped profile (i.e., quadratic relationship), whereas representation increases across the lifespan. EM was associated with representation at all ages, while it was associated with control only in the youngest children and in the adults groups. Representation mainly contributed to age-related difference in EM performance across development. Across aging, control, and to a lesser extent, representation, accounted for EM performance decline. These results showed that EM development and decline do not depend on the same cognitive resources, increased representation being crucial for EM development, and a decline in control with advancing age being responsible for the age-related change in EM performance.

The role of semantic memory in short-term recall: effect of strategic retrieval ability in an elderly population.

The present paper examines the relationship between two classic phenomena: semantic effects in short-term recall (STR) tasks, which are interpreted as indicating the involvement of long-term memory (LTM) in the functioning of short-term memory, on the one hand, and the existence of individual differences amongst elderly people in strategic retrieval ability (i.e., the ability to activate representations in LTM in a controlled way) on the other hand. Forty elderly participants completed a STR task under four different conditions which were thought to differentially involve LTM representations. Several executive functions, among which the strategic retrieval ability, were evaluated. The results showed that the participants who obtained the best performances in terms of strategic retrieval ability, and only in this executive ability, also exhibited better performances in the STR task, in particular when this task was performed under conditions which favored the use of LTM.

More dissociations and interactions within central executive functioning: a comprehensive latent-variable analysis.

The present study examined the separability of six executive functions (verbal storage-and-processing coordination, visuospatial storage-and-processing coordination, dual-task coordination, strategic retrieval, selective attention, and shifting) and their relationships, by means of confirmatory factor analysis. A set of tasks thought to primarily assess each target function was administered to 180 participants. The results demonstrated that five of the six functions initially considered were distinguishable albeit related constructs, with one of these functions combining inhibitory and strategic retrieval processes. The analyses failed to reveal a single dual-task coordination ability underlying performance on the dual-tasks. These findings provide further support for the fractionation of the central executive into several functions and also stress the need to approach executive functioning in terms of both dissociations within general functions and specific interactions between some of these functions.