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OS_23. Working memory

Saturday, October 01st,   2011 [16:20 - 17:20]


OS_23.1 - Where do individual differences in working memory capacity come from? A Time-Based Resource-Sharing account

Lucidi, A. & Barrouillet, P.

Department of Psychology, University of Geneva, Geneva, Switzerland

The aim of the present study was to identify the factors underlying individual differences in working memory (WM) capacity. According to the Time-Based Resource-Sharing (TBRS) model, there are at least two factors that should play a crucial role: processing efficiency and the efficiency of the refreshing mechanisms. This hypothesis was tested in three experiments. In Experiment 1, a computer-paced complex span task was used in which low-span and high-span individuals had to maintain series of letters while adding 2 to series of digits. Large individual differences were observed between the two groups. In Experiment 2, processing times were equated between groups by asking low-span individuals to add 1 instead of 2 to each digit. Individual differences were reduced but still significant. In Experiment 3, processing times were again equated and the time available to refresh memory traces was tailored to the processing speed of each group. This last manipulation resulted in a further reduction of individual differences, with no differences between low-span and high-span individuals in some conditions. This strongly suggests that both processing efficiency and the efficiency of the refreshing mechanisms are main factors underlying individual differences in WM capacity.

OS_23.2 - Time causes forgetting from working memory

Barrouillet, P. 1 , De Paepe, A. 2 & Langerock, N. 1

1 University of Geneva
2 Ghent University

The rapid forgetting of information is a ubiquitous and pervasive phenomenon. Surprisingly, after more than one century of investigation, the exact causes of this forgetting remain undecided. A venerable tradition has assumed that memory traces suffer from a temporal decay. However, modern psychology commonly assumes that forgetting is not due to decay, but to representation-based interference created by the intervening events occurring between encoding and retrieval. In two experiments, we show that time plays a causal role in forgetting from working memory. Adults were asked to remember series of items (either letters or spatial locations) while verifying multiplications before recall. The duration of the delay between encoding and recall was manipulated by presenting multiplications either in word (three x four = twelve) or digit format (3 x 4 = 12), the former taking longer to solve. In line with the temporal decay hypothesis, the longer solution times elicited by solving word multiplications resulted in poorer recall performance. Longer delays have the same effect on both verbal and visuo-spatial memory, making difficult to account for the effect by representation-based interference.

OS_23.3 - Attentional demand of maintenance mechanisms in verbal working memory

Corbin, L. 1 & Camos, V. 2

1 LEAD. Université de Bourgogne. Dijon, France
2 Université de Fribourg. Fribourg, Switzerland

Different mechanisms of maintenance of verbal information in working memory have been described. They vary in depth of processing of the memoranda, from a superficial recirculation of the phonological information by subvocal rehearsal, to the reactivation of the memory traces by attentional refreshing and to the association of the memory items with long-term memory knowledge through elaborative rehearsal. Previous works have shown that deeper processing by refreshing or elaborative rehearsal leads to better recall than when subvocal rehearsal is used. In the present study, we compared the impact on recall of a reduction of attention in a complex span task when participants were instructed to use one of these three maintenance strategies. Results revealed that the benefits of deeper processing are at the cost of higher attentional demand. Thus, increase in recall performance could emerge not through depth of processing but because the memoranda benefit from greater allocation of attention.

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