Verbal and visual-spatial working memory: What develops over a life span?

This study investigates whether age-related changes in the structure of 5 complex working memory (WM) tasks (a) reflect a general or domain specific system, (b) follows a similar trajectory across different age spans, and (c) contribute domain general or domain specific resources to achievement measures. The study parsed the sample (N = 2,471) into 11 age groups (mean ages of 6, 7, 8, 9, 11, 13, 15, 18, 26, 41, and 66 years), and compared their performances on verbal and visuospatial WM measures. Three important findings emerged: (a) a confirmatory factor analysis and Schmid-Leiman transformation to a high-order model solution supported a domain general factor model for the total sample as well as separately for children and adults, (b) performance on visual-spatial WM tasks as a function of age decreased at a faster rate than verbal WM tasks, and (c) both verbal and visual-spatial WM measures in concert with each other uniquely predicted reading and math measures, suggesting that a domain general WM system contributed to performance on achievement measures. The results support the notion that (a) complex WM tasks function as a domain general system and (b) the factor structure for children and adults on complex WM tasks was highly similar, even though there was evidence of differentiation among verbal and visual-spatial WM measures at certain age groups. (PsycINFO Database Record