Abstract
Our computerized operator support system microworld simulator with student operators approach is called COSSplay. COSSplay allows testing of specific interface elements such as alarm visualizations without the constraints of the surrounding nuclear control room elements typically associated with full-scope simulation studies. Approaches like COSSplay are ideal for first principles research in human factors and human-computer interaction. This paper highlights the uses of COSSplay as a complimentary approach to full-scope simulation studies for complex interface design.