ABSTRACT
In this chapter, the authors describe theoretical and methodological issues for evaluating interfaces as representations to support productive problem solving. They focus on elucidating a theoretic framework for evaluating displays than on detailing methodological prescriptions for research. Like the concept of ecological validity, the state space provides a framework for bringing normative considerations to research on problem solving. The critical premise of the theoretic framework is that meaning is a central consideration when evaluating interfaces. The challenge of representational design is to open up and broaden the perspective of the cognitive agent so that all the possibilities within the workspace are accessible. Value and goal constraints may be internalized by the operator or may be explicit design constraints for the system. In designing interfaces to determine mental models rather than to match existing mental models, perceptual skills of the human become critical.
