Working Memory Training Revisited: A Multi-Level Meta-Analysis of N-back Training Studies

Abstract

The efficacy of working memory (WM) training has been a controversial and hotly debated issue during the last years, and despite a large number of training studies and several meta-analyses, the matter has not yet been solved. We conducted a multi-level meta-analysis on the cognitive transfer effects in healthy adults who have been administered WM updating training with n-back tasks, the most common experimental WM training paradigm. Thanks to this methodological approach that has not been employed in previous meta-analyses in this field, we were able to include effect sizes from all relevant tasks used in the original studies. Altogether 203 effect sizes were derived from 33 published randomized controlled trials. In contrast to earlier meta-analyses, we separated task-specific transfer (here untrained n-back tasks) from other WM transfer tasks. Two additional cognitive domains of transfer that we analyzed consisted of fluid intelligence (Gf) and cognitive control tasks. A medium-sized transfer effect was observed to untrained n-back tasks. For other WM tasks, Gf, and cognitive control, the effect sizes were of similar size and very small. Moderator analyses showed no effects of age, training dose, training type (single vs. dual), or WM and Gf transfer task contents (verbal vs. visuospatial). We conclude that a substantial part of transfer following WM updating training with n-back is task-specific and discuss the implications of the results to WM training research.

Cognitive Training Does Not Enhance General Cognition

“…This pattern of results has been replicated in two other meta-analyses examining the effects of WM training on healthy adults [42] and typically developing children and young adolescents [43], respectively. Notably, these meta-analyses have found near-zero effects not only on tests of intelligence, but also on measures of cognitive control and academic skills.…”

Causal underpinnings of working memory and Stroop interference control: Testing the effects of anodal and cathodal tDCS over the left DLPFC

“…In other words, anodal tDCS might have improved training of executive functions more generally due to completing the Stroop task, which then persisted and transferred to more accurate responses in the n-back task 15 minutes after stimulation ended. However, this interpretation seems less plausible in the light of studies on training working memory, which have indicated that transfer between tasks tapping into different facets of executive functions are not robustly observed (Melby-Lervåg, Redick, & Hulme, 2016) or very small in effect size (Soveri, Antfolk, Karlsson, Salo, & Laine, 2017). n(sham) = 30; n(anodal) = 27; n(cathodal) = 31; c = congruent trial; i = incongruent trial Fig.…”

The Efficacy of Virtual Reality-Based Cognitive Training in Older Adults Non-Demented and with Mild Dementia: an One Group Pretest-Posttest Design

“…Similarly, the review of research on CS and CT programs for healthy older participants performed by Tardif and Simard (12) pointed out that the results are promising for memory, attention, executive functions, and speed of processing. Also metaanalyses of the influence of process-based CT, like working memory or cognitive control training, in healthy older adults demonstrated the effectiveness of such CI (13,14). Moreover, CT enhance stability of cognitive functioning across adulthood, as indicated the review by Eschen (15).…”