People chose different strategies for performing tasks, and that choice often plays a key role in performance. We investigate the use and evolution of strategic behavior in the Kanfer-Ackerman Air Traffic Controller© task, a fast-paced, dynamic task. We present strategies in two dimensions for one aspect of the task, examine how people use them and switch between them, and how their use relates to final performance. We also discuss the implications that the observed variety of strategic behavior has for cognitive modeling.

Cooper and Shallice (1995) raise many issues regarding the unified theories of cognition research program in general, and Soar in particular. In this paper, we examine one specific criticism of Newell's (1990) treatment of immediate behavior and use it to explain the notion of the modeling idiom within a cognitive architecture. We compare a dual-task model using Newell's architecture and idiom to two other models that use different architectures and idioms (EPIC and an experimental version of Soar). We also look at the models' dependency on their respective cognitive architectures, and the theory/implementation gap also identified by Cooper and Shallice (1995).

NTD-Soar is a model of the perceptual, cognitive, and motor actions performed by the NASA Test Director as he utilizes the materials in his surroundings and communicates with others to prepare for a Space Shuttle Launch. The model, built within the framework of a serial symbolic architecture, is based on a number of independently designed general cognitive capabilities as well as a cognitive analysis of a particular task. This paper presents a detailed description of the model and an assessment of its performance when compared to human data. NTD-Soar's ability to display human-like real-time performance demonstrates that symbolic models with a serial bottleneck can account for complex behaviors which appear to happen in parallel, simply by opportunistically interleaving small elements of the different subtasks.

There have been a number of production system models which have recently made substantial advances in modeling higher-level cognition. These type of model offers only comprehensive approaches to the modeling of higher level cognition. This symposium will involve presentations by four exemplars of this approach to cognitive modeling (ACT, CAPS, EPIC, and SOAR). The presentations will try to illustrate the range of applications to which such models are appropriate, what the similarities and differences are among the various architectures, and what some of the interesting research questions are within each architecture.