Working memory plays an essential role in complex cognition. Everyday cognitive tasks – such as reading a newspaper article, calculating the appropriate amount to tip in a restaurant, mentally rearranging furniture in one's living room to create space for a new sofa, and comparing and contrasting various attributes of different apartments to decide which to rent – often involve multiple steps with intermediate results that need to be kept in mind temporarily to accomplish the task at hand successfully. “Working memory” is the theoretical construct that has come to be used in cognitive psychology to refer to the system or mechanism underlying the maintenance of task-relevant information during the performance of a cognitive task (Baddeley & Hitch, 1974; Daneman & Carpenter, 1980). As reflected by the fact that it has been labeled “the hub of cognition” (Haberlandt, 1997, p. 212) and proclaimed as “perhaps the most significant achievement of human mental evolution” (Goldman-Rakic, 1992, p. 111), it is a central construct in cognitive psychology and, more recently, cognitive neuroscience.

Despite the familiarity of the term, however, it is not easy to figure out what working memory really is. To begin with, the term working memory is used in quite different senses by different communities of researchers. In the behavioral neuroscience and animal behavior fields, for example, the term is associated with the radial arm maze paradigm.

This final chapter starts where the previous chapter left off (Kintsch, Healy, Hegarty, Pennington, & Salthouse, Chapter 12). The main goal of the current chapter is to offer some thoughts we have about the future directions of working memory research. In particular, we present our own view of where the field stands and where it may be going in the belief that such reflection on the “big picture” is something this field needs.

The organization of the chapter is as follows. We will first present six points of general theoretical consensus that appear to be emerging among the models of working memory included in this volume. Despite this globallevel agreement about the nature of working memory, there are some important disagreements among different models. Thus, we will next point out some unresolved theoretical issues for each of the eight designated questions. In the last section, we will outline several issues that have not yet received much attention in the current models of working memory, but we believe will become increasingly important for future empirical and theoretical investigations.

General Theoretical Consensus About the Nature of Working Memory

At the beginning of Chapter 1, we quoted H. J. Eysenck's (1986) rather pessimistic remark about psychometric theories of intelligence1 and pointed out that some people would probably feel the same way about working memory: There are many different models of working memory out there, but they all seem so different that it is difficult to see how they relate to one another.