Shortened complex span tasks can reliably measure working memory capacity

Abstract

Measures of working memory capacity (WMC), such as complex span tasks (e.g., operation span), have become some of the most frequently used tasks in cognitive psychology. However, due to the length of time it takes to complete these tasks many researchers trying to draw conclusions about WMC forgo properly administering multiple tasks. But can the complex span tasks be shortened to take less administration time? We address this question by splitting the tasks into three blocks of trials, and analyzing each block's contribution to measuring WMC and predicting fluid intelligence (Gf). We found that all three blocks of trials contributed similarly to the tasks' ability to measure WMC and Gf, and the tasks can therefore be substantially shortened without changing what they measure. In addition, we found that cutting the number of trials by 67 % in a battery of these tasks still accounted for 90 % of the variance in their measurement of Gf. We discuss our findings in light of administering the complex span tasks in a method that can maximize their accuracy in measuring WMC, while minimizing the time taken to administer.

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

“…Despite including only half as many trials in total as the three classic computerized versions of the subtests (Unsworth et al, 2005), the CCS demonstrates similar psychometric properties. The satisfying qualities of the CCS indicate that short versions of complex span tasks may be used to provide an accurate measure of domain-general working memory, congruent with the conclusions of recent works (Foster et al, 2014;Oswald et al, in press). In other words, it is not necessary to have participants complete full versions of multiple complex spans to obtain a valid measure of their working memory capacity.…”

“…In other words, it is possible to construct a working memory test including several complex span tasks serving as subtests, with only a low number of trials per subtest, as long as the total number of trials across all subtests is sufficient to obtain a reliable measure. This idea is supported by a recent work indicating that classic complex span tasks retain significant validity even when reducing the number of trials by two-thirds, and that combining shortened versions of multiple complex span tasks yields a better measure than using a full-length version of a single task (Foster et al, 2014). Shortened versions of complex spans tasks are also emerging in the literature, and these tasks demonstrate adequate psychometric properties (Oswald, McAbee, Redick, & Hambrick, in press).…”

“…Similarly, even though assessing domain-specific working memory capacity may be of interest, the CCS should not be decomposed into verbal and spatial subtests due to the limited psychometric value of individual subtests. With only one or two subtests per domain, it is also likely that this approach would yield task-specific rather than domain-specific estimates of working memory capacity; in order to obtain a valid measure of domain-specific working memory capacity, it would be recommended to use at least three tasks per domain (Foster et al, 2014).…”

The development of a short domain-general measure of working memory capacity

“…Second, even though three administrations of each set size are typical for complex span measures of WMC (likely a tradition of the procedure established by Daneman & Carpenter, 1980), fewer administrations per set size would obviously reduce the time to complete a measure (see Foster et al, 2014). We therefore removed the third administration of all set sizes to determine whether the measure shortened in this manner would retain appropriate psychometric properties.…”

Working memory capacity and the scope and control of attention

“…In Data Set 2, test-takers performed three blocks of trials with each list length presented once per block. List length presentation was random within each block (see Foster et al, 2015 for more information on these tasks). The dependent variable was the number of items recalled in their correct serial position.…”