Pii: S0142-694x(02)00004-2

The thinking process of designers is one of the most important issues in design research. This paper intends to enlarge design thinking theory and research by taking a close theoretical and empirical look at the very basic elements of thinking in design. Based on theoretical assumptions, thinking in design is reduced to the four basic cognitive operations of generation, exploration, comparison and selection, which, in various combinations, are applied to the goal space and the solution space of a given problem as well as to the organisation of the collective process of teamwork. These basic cognitive operations can be mapped onto different stages of the design process, thus establishing a generic model of design team activity. The generic model can be used to describe both, activities directed towards the content of a design problem as well as activities towards the organisation of the group process. Three laboratory teams solving a complex design problem extending over six hours have been studied in order to investigate the collective thinking process. Team communication has been recorded and analysed sentence-by-sentence, with each communicative act being classified according to the generic model. Based on previous results in the psychology of human information-processing and decision-making, a two-process-theory of thinking in design teams is proposed capable of explaining the results from the empirical investigation. The implications of the two-process-theory for training and practice of designers are discussed. c 2002 Elsevier Science Ltd. All rights reserved.