The purpose of this study was to investigate the extent to which various speeded-related processes constrain the development of working memory in children, and whether these processes mediate the relationship between working memory and academic attainment. To that end, a sample of 112 children aged between 5 and 8 years were given four tasks measuring speed-related aspects of working memory performance, specifically basic speed of processing, articulation speed, forgetting rates, and memory scanning speed. Experimental measures of short-term memory ('simple span') and working memory ('complex span') were also give, as were standardised tests of reading [Sentence Completion Forms of the NFER-­Nelson (1998) Group Reading Test II Form A (6–14)] and mathematics [NFER-­Nelson (1994) Mathematics 6–14]. This data collection contains data from the second of four studies conducted on the associated ESRC grant (see Related Resources). The aim of this project is to build on previous psychological research with both children and adults to provide the most comprehensive model to date of the factors involved in the development of working memory performance in children. In doing so, the project will investigate the extent to which these factors are separable or inter-related. Also the project will assess how these factors contribute to mediating the strong relationships commonly observed between working memory and academic attainment. The research has four specific objectives: To determine whether age-related changes in short-term memory capacity are related to working memory development. To determine how age-related changes in processing speed are related to working memory development. To determine whether age-related changes in long-term memory utilisation are related to working memory development. To determine which of the above factors mediate the relationship between working memory performance and educational attainment. These objectives will be met in a set of empirical studies, using both existing and novel experimental measures. These measures will be related to academic attainment and measures of classroom behaviour. Each study will involve large samples of children in two age groups (around 5 and around 9 years of age).

This study used an empirical, experimental data collection method. All tasks, apart from the standardised measures of reading and mathematics were programmed using Runtime Revolution software and presented on MacBook Pro laptop computers. A total of 180 words were used in processing elements of the tasks, which were familiar concrete nouns, with age of acquisition of under 6.2 years. No words were repeated within or between tasks in a single testing session. All audio material was presented through the internal laptop speakers using pre-recorded male voices. Where a processing task was used in any of the tasks (including decision making in the memory scanning task), reaction times (RTs) were recorded when the child selected their response key (z or /) on the computer keyboard. ‘z’ corresponded to correct, and ‘/’ to incorrect in every task. Participants were assessed individually in three testing sessions lasting approximately 30 minutes each. In sessions 1 and 3, children completed 4 tasks, and in the middle session they were tested on 3 tasks. In session 1, they completed the first verbal and visual baseline processing assessment, digit span, and memory scanning, in that order. In session 2, they completed verbal-visual complex span, articulation speed, and verbal forgetting, in that order. In session 3, they completed the second verbal and visual baseline processing assessment, verbal-verbal complex span, and visual forgetting, in that order (see attached 'methodology' file for details on these tasks). In addition to the memory measures given in these experimental testing sessions, all children were tested on the Sentence Completion Forms of the NFER-Nelson (1998) Group Reading Test II Form A (6-14) and the age appropriate test from the NFER-Nelson (1994) Mathematics 6-14 series in separate sessions. The full sample consisted of 112 children (51 males, mean age 7 years 1 month, range 5 years 8 months to 8 years 8 months, 64 in School Year 1 and 48 in School Year 3). Eight participants were absent during phases of the data collection and so failed to complete the experimental memory tasks. Equipment failure resulted in a further 9 participants’ data being lost for the articulation speed task. Eleven participants were absent at the time when the reading and mathematics assessments were given. As a result, a full data set that include all measures is available for 87 children (50 in Year 1, 37 in Year 3).