Working Memory Deficits in individuals With and Without Mental Retardation

The authors critically examine the issue of working memory in mental retardation. Different outcomes reported in the literature could be due to the different aspects of working memory tested. It was hypothesized that working memory functions can be distinguished according to a control continuum: a deficit of an individual with mental retardation in working memory tasks should be more evident to the extent to which they require higher control. 30 individuals with mental retardation, aged between 7 and 17, with a mean mental age of 5 years 6 months, and 30 children without mental retardation, matched for mental age, were given a battery of four working memory tests requiring different levels of control: low (forward word span), medium-low (backwards word span), medium-high (listening word span), and high (dual task span). Results confirmed the hypothesis that an increase in the gap between the two groups corresponds to an increase in the control required by the task. Results are discussed for their implications on working memory models and the role of working memory in intelligence.