The Reflective Eye: Visual Reasoning in the Sketch

Despite recent advances in our understanding of design thinking, we still lack a comprehensive theoretical approach to cognitive processes in design and particularly to visual reasoning. Of scientific interest in its own right, understanding non-verbal reasoning is also relevant to a wide range of subjects in the area of visual data resources for designers. This paper presents research into visual reasoning through the study of cognitive acts and processes associated with design drawing. Employing case studies in the design sketch, a vocabulary is defined for describing phenomena of visual reasoning in design as they are revealed in the sketch. Classes of reasoning processes are proposed as strings of graphic acts of state transformation. A theoretical schema is developed which relates the individual act of visual reasoning manifested in the sketch, of sketch sequences, with larger global cognitive phenomena such as analogical or associative reasoning in design. Based upon this schema, a symbol system for these acts and processes is proposed as a coding technique in the observation, analysis and recording of non-verbal processes in design