Despite our phenomenological experience of a rich and detailed awareness of the objects in our environment, our immediate visual awareness is actually limited to a very small number of items at any given moment. The cognitive system that is thought to underlie this ability is visual working memory, which maintains active representations about objects in the environment so that they may be manipulated or acted upon. The storage capacity of this important system is well known to be highly limited. Working memory capacity is also well known to be subject to substantial individual differences. For over a century, individual differences in working memory capacity have been assumed to reflect "how many" pieces of information an individual can hold in memory at one time. In contrast, recent evidence suggests that variability in memory capacity may not be due to differences in absolute storage capacity, but instead may be due to differences in the ability to control attention. That is, because capacity is limited, efficient attentional selection mechanisms are necessary for controlling which items are maintained in working memory and which items will be excluded.
With support from the National Science Foundation, Dr. Edward Vogel and his colleagues at the University of Oregon will use behavioral and electrophysiological methods to examine the attention processes that control access to visual working memory and how these processes may differ across high and low working memory capacity individuals. They have recently developed a highly sensitive new neural method for measuring the amount of information a subject is currently holding in working memory, and will use this approach to establish behavioral and electrophysiological signatures of individual differences in control over working memory-related attentional processes. This work is important in part because an individual's ability to perform complex functions such as reasoning and mathematics has been shown to be greatly influenced by his or her working memory capacity. That is, high working memory capacity individuals tend to score much higher on general aptitude or scholastic achievement tests than low working memory capacity individuals. Working memory capacity is also known to be substantially lower in individuals with schizophrenia and attention deficit/hyperactivity disorder. Thus, a full understanding of the factors that underlie individual differences in working memory capacity may have broad implications in both educational and clinical settings.
