Sources of variability in working memory in early childhood: A consideration of age, temperament, language, and brain electrical activity

This study investigated age-related differences in working memory and inhibitory control (WMIC) in 31/2, 4-, and 41/2-year-olds and how these differences were associated with differences in regulatory aspects 2 of temperament, language comprehension, and brain electrical activity. A series of cognitive control tasks was administered to measure WMIC ability, including the Stroop-like day-night and the yes-no tasks. Baseline and task electroencephalographic data were collected. The Children's Behavior Questionnaire was used to assess caregiver perceptions of temperament with a particular interest in the effortful control and surgency factors, and language comprehension was measured with the Peabody-Picture Vocabulary Test-III. The results of this study demonstrated differential temperament-cognition relations for the three age groups, as positive associations were found between WMIC and effortful control for the 31/2- and 4-year-olds and negative associations were found between WMIC and surgency for the 41/2-year-Olds. An increasingly robust relation between WMIC and language comprehension was demonstrated across the three age groups, as well as differential patterns of task-related brain electrical activity. (c) 2007 Elsevier Inc. All rights reserved.