Abstract
We describe an approach to investigating design cognition which involved comparing prescriptive theories of good design practice with observations of actual design behaviour. The tenet of prescriptive theory which formed the focus of the research is the idea that designers should generate and evaluate multiple design alternatives in order to increase the chances of attaining better design solutions than might arise if they fixated upon an initial solution. Our study focused upon six professional electronic engineers attempting a novel integrated-circuit design problem. Verbal-protocol data revealed: (i) a failure to search for alternative solutions; (ii) a marked inclination to stick with early 'satisficing' solution ideas even when these were showing deficiencies; and (iii) only superficial modelling and assessment of competing alternatives when such options were actually considered. We argue that while minimal solution search in design may sometimes be caused by motivational factors and working-memory limitations, its major determinant relates to inhibitory memory processes that arise subsequent to the recognition-based emergence of familiar design solutions. We conclude by exploring the implications of minimal solution search for design support, with particular reference to an agent-based indexing system which we are developing in order to facilitate the pursuit of design alternatives in engineering contexts. © 1998 Published by Elsevier Science B.V.