Requirements for design-relevant psychological models

Cognitive engineering is largely concerned with creating environmental designs to support skillful and effective human activity. Psychological models must meet special constraints in order to effectively support this enterprise. The goal is to identify a set of constraints that models must meet if they can usefully guide design. The author discusses two types of constraints on acceptable psychological models that arise due to the need to represent both internal and external influences on cognition and behavior. The first set of constraints is structural. The second set of constraints concerns the content of acceptable models. It is concluded that cognitive engineering most requires models capable of representing the human and environment as an integrated unit, and which represent the activities underlying fluent, skilled behavior