ABSTRACT
Cognitive impairments are important correlates of functional outcome in children with reading disabilities (RD) and/or math disabilities (MD). Of these impairments, working memory (WM) has been the focus of extensive research efforts because it plays a central role in several domains of cognition including language comprehension, fl uid intelligence, writing, arithmetic, and problem solving (Gathercole, Alloway, Willis, & Adams, 2006; also see Swanson & Siegel, 2001, for a review) as well as overall cognitive development (e.g., Case, 1995; de Ribaupierre & Lecerf, 2006). Further, WM impairments have been related to specifi c aspects of RD, such as problems in reading comprehension (Swanson, 1999b), as well as to specifi c aspects of MD, such as weaknesses in word problem solving (Swanson & Beebe-Frankenberger, 2004; Swanson, Jerman, & Zheng, 2008). We fi nd, as do others, that children with normal intelligence but who suffer RD and/or MD experience considerable diffi culty on WM tasks (e.g., Andersson, 2008; Bull, Johnston, & Roy, 1999; Chiappe, Hasher, & Siegel, 2000; De Beni, Palladino, Pazzaglia, & Cornoldi, 1998; de Jong, 1998; Gathercole et al., 2006; Passolunghi, Cornoldi, & De Liberto, 1999; Siegel & Ryan, 1989). There is also evidence that WM impairments may play a critical role in mediating some of the academic problems in children with RD and MD (e.g., see de Jong, 1998; Gathercole et al., 2006; Swanson & Berninger, 1995; Willcutt, Pennington, Olson, Chhabildas, & Hulslander, 2005). Although WM is integrally related to a number of academic behaviors, relatively few studies have been undertaken to systematically explore whether growth in WM underlies growth in reading and/or math performance. The purpose of this chapter is to review some of our recent work that provides an empirical foundation for the view that reading disabilities (RD) and/ or math disabilities (MD) refl ect a fundamental defi cit in the development of WM. We review evidence that suggests that these defi cits, depending on task demands, manifest themselves as a domain-specifi c constraint (i.e., the ineffi - cient accessing of phonological representations) or a domain-general constraint (i.e., capacity limitations in controlled attentional processing). That is, as an extension of research that localizes problems in RD to a phonological system (e.g., short-term memory or STM for words) or MD to constraints to number recall (e.g., short-term memory or STM for numbers), we think fundamental
processing differences also emerge between children with specifi c learning disabilities in RD or MD that cut across tasks that involve the controlledattentional processing of verbal and visual-spatial information. How constraints in the executive system operate independently and potentially interact with constraints in the phonological system will also be discussed.
