In the present study, a novel working memory (WM) training paradigm was used to test the malleability of WM capacity and to determine the extent to which the benefits of this training could be transferred to other cognitive skills. Training involved verbal and spatial versions of a complex WM span task designed to emphasize simultaneous storage and processing requirements. Participants who completed 4 weeks of WM training demonstrated significant improvements on measures of temporary memory. These WM training benefits generalized to performance on the Stroop task and, in a novel finding, promoted significant increases in reading comprehension. The results are discussed in relation to the hypothesis that WM training affects domain-general attention control mechanisms and can thereby elicit far-reaching cognitive benefits. Implications include the use of WM training as a general tool for enhancing important cognitive skills.
Practice can yield remarkable levels of achievement but little generalization. For example, Ericsson and Chase (1982) reported the illustrative case of a college student who, following many hours of practice on a digit-span task (an often used measure of short-term memory [STM]), could successfully recall over 80 randomly ordered digits. However, the individual was limited to a typical STM span of about seven items for other, even closely related, memoranda. The specificity of the improvements observed in that and other classical studies of skill acquisition and expertise have led many to conclude that the benefits of practice on a given task do not generally extend into other realms of performance (Chase & Simon, 1973; Engle & Bukstel, 1978). By this account, although individuals may exhibit innate differences in certain domain-general capacities, training strategies seeking to promote superior performance through influence on these general capacities would be destined to fail.
Several recent studies, however, have invigorated an interest in the plausibility of using repetitive mental exercise to enhance one domain-general ability-working memory (WM)-and, in so doing, to concurrently improve performance in other cognitive skills (Jaeggi, Buschkuehl, Jonides, & Perrig, 2008; Klingberg et al., 2005; Persson & Reuter-Lorenz, 2008). Training regimens used in these and other recent efforts appear to have targeted domain-general processes that individuals utilize to broadly support complex cognition. For example, in a study by Verhaeghen, Cerella, and Basak (2004), WM training was shown to influence recall from WM by expanding the capacity of attention. Likewise, others have demonstrated that WM training can impact domain- general cognitive control mechanisms (Klingberg et al., 2005; Klingberg, Forssberg, & Westerberg, 2002), interference resolution processes (Persson & Reuter-Lorenz, 2008), WM updating processes (Dahlin, Neely, Larsson, Bäckman, & Nyberg, 2008), and even general fluid intelligence (Jaeggi et al., 2008).
Although it provides a very promising foundation, the small corpus of existing WM training studies is limited in two important ways. First, prior demonstrations of transfer included measures closely related to those used to estimate WM itself, rather than to more distant tasks. To address this limitation, we sought to examine a broader battery of measures with the expectation that other tasks known to correlate with individual differences in WM capacity might also benefit from WM training. Second, previous studies utilized training tasks that are not commonly employed in the basic behavioral or psychometric literatures (e.g., atypical variants of the n-back task in Verhaeghen et al.  and Jaeggi et al. ; a battery of video-gamelike tasks, such as that used in Klingberg et al., 2005). Thus, previous findings are somewhat disjointed from the larger behavioral literature and offer only limited insights into the specific WM mechanisms influenced by training (e. …