Whichever way you choose to categorize, working memory helps you learn

Abstract

There has been growing interest in the relationship between the capacity of a person's working memory and their ability to learn to categorize stimuli. While there is evidence that working memory capacity (WMC) is related to the speed of category learning, it is unknown whether WMC predicts which strategies people use when there are multiple possible solutions to a categorization problem. To explore the relationship between WMC, category learning, and categorization strategy use, 173 participants completed two categorization tasks and a battery of WMC tasks. WMC predicted the speed of category learning, but it did not predict which strategies participants chose to perform categorization. Thus, WMC does not predict which categorization strategies people use but it predicts how well they will use the strategy they select.

Keywords:

• Categorization
• Working memory capacity
• Strategy use

Acknowledgments

Preparation of this paper was facilitated by a Discovery Grant from the Australian Research Council to the second author and Gilles Gignac, an Australian Professorial Fellowship to the second author, and a Jean Rogerson Postgraduate scholarship to the first author. We wish to thank Charles Hanich and Abel Oh for assistance with data collection. We also wish to thank Daniel R. Little for his helpful comments on the manuscript.

Notes

¹ Participants who completed the 5–4 task and correlated-cues tasks in different sessions also completed (a) one additional transfer phase of the 5–4 task after the WMC tasks in the second session and (b) Raven's Standard Progressive Matrices (Raven, Raven, & Court, 2000) at the end of the first session. The responses to the extra transfer block were inspected but showed no effects of interest; as such, we do not report the results of the extra tests here. The data from Raven's Standard Progressive Matrices were used for a separate study.

² Using structural equation modelling (SEM) we confirmed that (a) WMC tasks all loaded onto a single WMC factor when the MU1 and MU2 tasks were combined, (b) loadings on the WMC factor showed minimal change when the MU1 task was used alone, compared to when the MU tasks were combined, and (c) the loadings of the combined MU tasks were comparable to previously reported loadings using the OS, SS, SSTM, and MU1 tasks (Lewandowsky et al., 2010). We therefore present only the analysis using a combined MU score.

³ We did not relate learning performance to strategy use in the correlated-cues task because the type of stimuli—alien cells versus rockets—turned out to be strongly associated with both category learning and strategy use.