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  • Cited by 66
  • Print publication year: 1999
  • Online publication date: June 2012

5 - Modeling Working Memory in a Unified Architecture: An ACT-R Perspective



We describe a model of working memory that is developed within the ACT-R cognitive architecture. Some of its main features are derived from the basic features of ACT-R:

(1) Processing depends on the current goal of the system.

(2) The accessibility of declarative and procedural knowledge varies with experience.

In addition, the following features are important to working memory in particular:

(3) There is a limited attentional resource, focused on the current goal, that increases the accessibility of goal-relevant knowledge relative to other knowledge.

(4) In more complex and memory-demanding tasks, this limited resource is spread more thinly thus impairing retrieval of goal-relevant items.

(5) The “capacity” of this attentional resource may vary from person to person, influencing the ability to access goal-relevant information across domains.

In performing almost any cognitive task, one must engage working memory to maintain and retrieve information during processing. For example, in mental arithmetic (e.g., multiplying large numbers without pencil and paper), one must hold intermediate results in memory while solving the problem. Similarly, in sentence processing, one must maintain various syntactic and semantic structures until subsequent processing reveals their roles. Because working memory is involved in so many tasks, studying its characteristics and its impact on cognitive processes is critical to gaining a deeper understanding of how people perform cognitive tasks in general.

Past research highlights two important results, each of which demonstrates that working memory modulates task performance.