No evidence of intelligence improvement after working memory training: A randomized, placebo-controlled study.

Abstract

Numerous recent studies seem to provide evidence for the general intellectual benefits of working memory training. In reviews of the training literature, Shipstead, Redick, and Engle (2010, 2012) argued that the field should treat recent results with a critical eye. Many published working memory training studies suffer from design limitations (no-contact control groups, single measures of cognitive constructs), mixed results (transfer of training gains to some tasks but not others, inconsistent transfer to the same tasks across studies), and lack of theoretical grounding (identifying the mechanisms responsible for observed transfer). The current study compared young adults who received 20 sessions of practice on an adaptive dual n-back program (working memory training group) or an adaptive visual search program (active placebo-control group) with a no-contact control group that received no practice. In addition, all subjects completed pretest, midtest, and posttest sessions comprising multiple measures of fluid intelligence, multitasking, working memory capacity, crystallized intelligence, and perceptual speed. Despite improvements on both the dual n-back and visual search tasks with practice, and despite a high level of statistical power, there was no positive transfer to any of the cognitive ability tests. We discuss these results in the context of previous working memory training research and address issues for future working memory training studies.

On the validity and generality of transfer effects in cognitive training research

“…7 control condition respectively (e.g., Shipstead et al, 2012;Redick et al, 2013, but see Boot et al, 2013). Following this logic, all participants would receive challenging interventions but one focusing on one ability (e.g., working memory) and the other focusing on another ability (e.g., processing speed).…”

“…At least, they need to specify ways to distinguish differential impacts of the two abilities. Thus, the original idea to control for group differences in motivation and outcome expectancy (Shipstead et al, 2012;Redick et al, 2013) could then be extended to further validate the construct of training-related change. The training and assessment of multiple latent constructs (e.g., working memory and perceptual speed) as well as the theoretical model predicting the associations between the trained constructs and the targeted transfer construct (e.g., fluid intelligence) would allow for tests of discriminant validity of training-related change (Campbell & Fiske, 1959).…”

“…We summarized possible strategies to strengthen the assumption that transfer effects actually represent effects at the level of the targeted construct. These calls for analyses of training-related gain at the latent level Schmiedek et al, 2010;Shipstead et al, 2010; and the corresponding investigations of measurement invariance, and for adequate placebo conditions (Boot et al, 2011;2013;Redick et al, 2013;Shipstead et al, 2012), have been voiced before. Here, we review the recent training literature, investigating if these calls have been heard and if respective strategies have been implemented in practice.…”

“…While 26 studies investigated the effects of practice on single tasks like the dual n-back task (e.g. Chooi & Thompson, 2012;Jaeggi et al, 2008;Rudbeck et al, 2012;Redick et al, 2013;Salminen, Strobach, & Schubert, 2012), the dual task (e.g. Bherer, Kramer, & Peterson, 2008;Lussier, Gagnon, & Bherer, 2012;Mackay-Brandt, 2011), or the task-switching paradigm (e.g.…”

LearningRx Cognitive Training Effects in Children Ages 8–14: A Randomized Controlled Trial

“…Although transfer from working memory training to fluid intelligence has been documented in several small studies (Jaeggi, Buschkuehl, Jonides, & Perrig, 2008; Jaušovec & Jaušovec, 2012), skepticism continues to permeate the field (Redick et al, 2013). This bent is understandable given the number of non‐significant findings.…”