Complex span and n-back measures of working memory: A meta-analysis

Abstract

Working memory is a construct of primary relevance to many areas of psychology. Two types of tasks have been used to measure working memory, primarily in different research areas: Complex span tasks are commonly used in behavioral studies in the cognitive and individual-differences literature, whereas n-back tasks have been used more frequently in cognitive neuroscience studies investigating the neural underpinnings of working memory. Despite both categories of tasks being labeled as "working memory" measures, previous empirical studies have provided mixed evidence regarding the shared amount of overlapping processes between complex span and n-back tasks. The present meta-analysis showed that the complex span and n-back tasks are weakly correlated, although significant heterogeneity across studies was observed. A follow-up analysis of unpublished data indicated that the sample composition affects the relationship between the complex span and n-back tasks, following the law of diminishing returns. Finally, a separate meta-analysis indicated that the simple span and n-back tasks are correlated to the same extent as are the complex span and n-back tasks. The present findings indicate that the complex span and n-back tasks cannot be used interchangeably as working memory measures in research applications.

Individual Differences and Long-term Consequences of tDCS-augmented Cognitive Training

“…In the absence of a true unstimulated baseline of the actual training task, the visual n-back was chosen as the closest reasonable proxy. Although our pretest battery consisted of four WM tasks-visual n-back, auditory n-back, digit span, and Corsi blocks-the latter two are span tests, which correlate only weakly with n-back performance (Redick & Lindsey, 2013), whereas the former two are structurally similar to the trained visuospatial n-back. Although our previous report (Au et al, 2016) made the a priori decision to combine these two n-back tests into a composite measure to test for group differences in baseline, we ended up finding strong transfer effects only in the visual, but not auditory, n-back test.…”

The composite complex span: French validation of a short working memory task

“…Complex spans typically demonstrate excellent psychometric properties (Conway et al, 2005;Redick et al, 2012): they have good internal consistency (Redick et al, 2012), stability over time (Klein & Fiss, 1999), and convergent and criterion validity (Redick et al, 2012). By contrast, other tasks frequently used as working memory measures are not nearly as successful: for example, the backward span is more strongly associated with short-term memory than with working memory (e.g., Engle, Tuholski, Laughlin, & Conway, 1999) and the n-back task demonstrates limited reliability as well as limited correlations with other working memory measures (Jaeggi, Buschkuehl, Perrig, & Meier, 2010, Redick & Lindsey, 2013.…”

The effectiveness of working memory training – points to consider for future research

“…Some authors rightly note that when measurement of near transfer is constructed analogically to the methods of training, it is easy to obtain positive results confirming the presence of transfer Shipstead, Redick, et al, 2012). On the other hand, there are also arguments saying that we do not dispose of interchangeable and at the same time not similar measures of WMC (Redick & Lindsey, 2013). Thus, is it a good idea to administer two most popular tests, i.e.…”

“…The first group entails complex span tasks and the second group entails n-back tasks (Kirchner, 1958) -for a review see Redick and Lindsey, 2013.…”

“…complex span tasks together with n-back task? Redick and Lindsey (2013) conducted a meta-analysis of studies analysing the correlation between span tasks and n-back tasks. What they found is that there exist only weak correlation between them.…”