Naming speed, automatic inhibition and effortful inhibition in a working memory task in children with arithmetic learning difficulties.

We report a study aimed at investigating rate of access to numerical and non-numerical information in long-term memory and functioning of automatic and effortful cognitive inhibition processes in children with Arithmetical Learning Disabilities (ALD). A group of children with ALD, of age 10,3 years, and a group of gender-age-matched controls were involved in the study. Rate of access was measured through digit- and letter- naming tasks, automatic cognitive inhibition was measured using a negative priming paradigm, and effortful cognitive inhibition was measured rating intrusion errors in the well known Daneman and Carpenter’s (1980) working memory task. No evidence for dysfunction of the automatic inhibition processes was found. On the contrary, children with ALD were slower than controls in speed of activating both numerical and non-numerical information from long-term memory. Moreover, they showed lower working memory span than controls and more intrusion errors in the Listening Span task, as they remember more non target words embedded in the sentences than controls. Consistent with Engle (2002) and Passolunghi and Siegel (2001, 2004), the interpretation of these results is that the working memory performance of children with ALD is damaged by an inability to inhibit irrelevant information that overloads the working memory system.