Mapping the Developmental Constraints on Working Memory Span Performance.

Abstract

This study investigated the constraints underlying developmental improvements in complex working memory span performance among 120 children of between 6 and 10 years of age. Independent measures of processing efficiency, storage capacity, rehearsal speed, and basic speed of processing were assessed to determine their contribution to age-related variance in complex span. Results showed that developmental improvements in complex span were driven by 2 age-related but separable factors: 1 associated with general speed of processing and 1 associated with storage ability. In addition, there was an age-related contribution shared between working memory, processing speed, and storage ability that was important for higher level cognition. These results pose a challenge for models of complex span performance that emphasize the importance of processing speed alone.

Working memory span development: A time-based resource-sharing model account.

“…Regression analyses in Experiment 2 revealed that the development of the rate of reactivation cannot be totally accounted for by developmental changes in processing speed. This independence was confirmed by Bayliss et al (2005), who observed that the contributions on complex spans of speed of processing and rate of reactivation were separable and their developmental variations distinguishable. However, the same authors noted that this independence contradicts the TBRS model in which processing and storage (including the refreshment of memory traces through covert memory retrieval) rely on the same limited attentional resource.…”

“…This developmental improvement in efficiency could be due to two main sources. As Bayliss et al (2005) suggested, the first is an age-related increase in the reactivation rate when attention is focused on memory items. This reactivation could consist in rehearsing the verbal material to be maintained within the phonological loop or in refreshing memory traces through a covert retrieval process.…”

“…First, as noted by Bayliss et al (2005), the independence between processing speed and rate of reactivation is relative, and the two processes are likely to be related to a general factor, as the TBRS model assumes. Second, the same authors acknowledge that there is a general increase in basic cognitive speed but that this increase interacts with other cognitive processes as development continues, resulting in separate developmental trajectories for the processing speed and reactivation mechanisms.…”

How quickly they forget: The relationship between forgetting and working memory performance.

“…As a consequence of this, the speed with which individuals complete the processing operations leads to variation in the time during which forgetting can occur whilst maintenance activities are prevented. Evidence to support this suggestion comes from a recent study by Barrouillet et al (2012), who showed that lengthening the duration of the processing activity whilst maintaining a constant time between the end of each processing activity and presentation of the subsequent storage item (i.e., the time available for restoring or refreshing the memory trace) resulted in poorer memory performance, consistent with the idea that longer processing leads to greater forgetting (see also, Bayliss et al, 2005, who showed that age-related changes in a speed of processing variable accounted for unique variance in working memory span performance). In addition, by systematically manipulating the amount of time during which children were engaged in processing and the time they had available for refreshing memory items, Barrouillet et al (2009) were able to show that the slope relating the time available for refreshing memory items with working memory span performance was steeper in older relative to younger children.…”

“…colleagues (2004, 2007;Barrouillet, Gavens, Vergauwe, Gaillard, & Camos, 2009; see also Bayliss, Jarrold, Baddeley, Gunn, & Leigh, 2005;Jarrold & Bayliss, 2007) argued that engaging in the processing activity of the working memory span task prevents individuals from carrying out active maintenance of the to-be-remembered items (cf. Barrouillet & Camos, 2001;Towse, Hitch, & Hutton, 2002).…”