An Embedded-Processes Model of Working Memory

FIVE CENTRAL FEATURES OF THE APPROACH The embedded-processes model of working memory relies upon the following five principles, which emphasize links between memory and attention. (1) Working memory information comes from hierarchically arranged faculties comprising: (a) long-term memory, (b) the subset of longterm memory that is currently activated, and (c) the subset of activated memory that is in the focus of attention and awareness. (2) Different processing limits apply to different faculties. The focus of attention is basically capacity limited, whereas activation is time limited. The various limits are especially important under nonoptimal conditions, such as interference between items with similar features. (3) The focus of attention is controlled conjointly by voluntary processes (a central executive system) and involuntary processes (the attentional orienting system). (4) Stimuli with physical features that have remained relatively unchanged over time and are of no key importance to the individual still activate some features in memory, but they do not elicit awareness (i.e., there is habituation of orienting). (5) Awareness influences processing. In perception it increases the number of features encoded, and in memory it allows new episodic representations to be available for explicit recall. Two prior integrative reviews of information processing, an article (Cowan, 1988) and a book (Cowan, 1995), describe a view that will serve as my basis for discussing working memory.