This research aims to collect empirical evidence on the nature of design by investigating the question: What role do procedural activities (where each design step reflects a unit in a linear process) and contextual activities (an action based on the situation, environment and affordances) play in the generation of creative insights, critical moves, and the formation of design concepts in the reasoning process? The thesis shows how these activities can be identified through the structure of a linkograph, for better understanding the conditions under which creativity and innovation take place. Adopting a mixed methodology, a deductive approach evaluates the existing models that aim to capture the series of design events, while an inductive approach collects data and ethnographic observations for an empirical study of architectural design experiments based on structured and unstructured briefs. A joint approach of quantitative and qualitative analyses is developed to detect the role of evolving actions and structural units of reasoning, particularly the occurrence of creative insights (‘eureka’ and ‘aha!’ moments) in the formation of concepts by judging the gradual transformation of mental imagery and external representations in the sketching process. The findings of this research are: (1) For any design process procedural components are subsets in solving the design problem for synchronic concept development or implementation of the predefined conceptual idea, whereas contextual components relate to a comprehensive view to solve the design problem through concept synthesis of back- and forelinking between the diachronic stages of the design process. (2) This study introduces a new method of looking at evolving design moves and critical actions by considering the time of emergence in the structure of the reasoning process. Directed linkography compares two different situations: the first is synchronous, looking at relations back to preceding events, and the second is diachronic, looking at the design state after completion. Accordingly, creative insights can be categorised into those emerging in incremental reasoning to reframe the solution, and sudden mental insights emerging in non-incremental reasoning to restructure the design problem and reformulate the entire design configuration. (3) Two architectural designing styles are identified: some architects define the design concept early, set goals and persevere in framing and reframing this until the end, whereas others initiate the concept by designing independent conceptual elements and then proceed to form syntheses for the design configuration. Sudden mental insights are most likely to emerge from the unexpected combination of synthesis, particularly in the latter style. In its contribution to design research and creative cognition this dissertation paves the way for a better understanding of the role of reflective practices in design creativity and cognitive processes and presents new insights into what it means to think and design as an architect
