This project aims to futher our understanding of the neural representations that underlie working memory. Working memory refers to the active maintenance of information in the service of complex cognitive tasks such as problem solving and planning. The team of investigator with study how the unique demands placed on the working memory system shape its representations during learning and development, and how these representations affect the use of working memory by the cognitive system as a whole. Their primary source of insight into this process will come from a computational analysis, which will be used to integrate and explore relevant findings from neurobiology and developmental and adult cognition. The primary hypothesis is that to maintain information in an active state over delays and in the face of interference, working memory representations should be discrete. A discrete representation admits to only a finite set of possible states, rather than representing continuous states. For example, the integers from 1 to 100 form a discrete set, in contrast to the real numbers in this range. Discreteness imparts a measure of robustness to the representation because small amounts of "noise" can be overcome by interpreting an observed state as the nearest discrete stat. From the central property of discreteness, a number of other properties follow. For example, discrete representations should be more categorical, more easily verbalize, better for perceiving or performing a sequence of steps, and more accessible to awareness. All these properties have component of the proposed research is to explore the idea that they all follow from the more basic property of dicreteness. The initial goal of the project will be establish through experimental studies the validity of the hypothesis that working memory representations are indeed discrete. This will be done by exploring a key behavioral consequence of this hypothesis: working memory representations should be more categorical than other representations. This predicition will be investigated with a set of existing empirical paradigms that have elucidated variables that affect the working memory system, including developmental age, delay, dual-task demands, and brain damage. Working memory plays a central role in most accounts of complex human behavior, because working memory is required in any task that involves multiple stos ir a temporally extended focus of attention. This kinds of tasks are important and pervasive throughout society, including: economic, political, and military planning; air-traffic control; and scientific research, to name just a few. It is essential to understand the nature of the representations in the working memory system and to understand how people learn to use working memory in the service of complex behavior. This research will advance our knowledge in this important area, and may provide insight into techniques for rehabilitation of working memory following brain injury and techniques for assisting the development of working memory in children.
