Theory and measurement of working memory capacity limits

Abstract We review the evidence for various kinds of limit in the capability of working memory, the small amount of information that can be held in mind at once. To distinguish between types of limit in working memory, we invoke metaphors of space (capacity), time (decay and speed), and energy (control of attention). The review focuses primarily on recent evidence on a limit in how many chunks can be held in working memory, how this kind of limit can be measured, and how it can be distinguished from other types of limits. We explore the theoretical and practical importance of different working memory limits in research that is nomothetic (referring to general laws) and ideographic (referring to individual and group differences). The appropriate measure of working memory depends on one's holistic or analytic scientific interest.