Towards a model of how designers mentally categorise design information

This study aims to explore how designers mentally categorise design information during the early sketching performed in the generative phase. An action research approach is particularly appropriate for identifying the various sorts of design information and the cognitive operations involved in this phase. Thus, we conducted a protocol study with eight product designers based on a descriptive model derived from cognitive psychological memory theories. Subsequent protocol analysis yielded a cognitive model depicting the mental categorisation of design information processing performed by designers. This cognitive model included a structure for design information (high, middle, and low levels) and linked cognitive operations (association and transformation). Finally, this paper concludes by discussing directions for future research on the development of new computational tools for designers. * Corresponding author. Tel.: +33 01 44 24 63 89; fax: +33 01 44 24 63 59. E-mail addresses: [email protected], [email protected] (J.E. Kim). ‘‘conceptualisation’’) [7,8,13,19]. During the early stages of the design process, designers integrate various levels of information to reduce abstraction by adding constraints [7,8]. Bouchard et al. [8] and references therein, interpreted the cognitive processes of designers during the early stages in terms of information processing. According to this view, designers engage in an informational cycle that includes informative, generative, and decision-making phases (evaluation–selection) to produce intermediate representations (IRs) that develop in an evolutionaryway. Goldschmidt [25] defined IRs as mental or physical images used during the entirety of the design process. IRs can be implicit or explicit, appearing as design briefs, trend boards, 2D/3D sketches, styling models, digital geometrical models, mock-ups, prototypes, etc. They are used strategically according to the design context, design phase, design purpose, cultural context, etc. Given that the early stages of design are considered to be among the most cognitively intensive in the design process [34], several studies based on interior and architectural designs have been pioneered to understand the sketching activities of designers, especially those performed during the generative phase [6,25,41,43]. Since the early 1990s, a few studies dedicated to the sketching activity of designers have emerged in mechanical engineering design; these include Ulman et al. [46], Goel [24], Purcell and Gero [37], and Yang [47]. To date, little research has addressed issues related to the inspirational sources used by designers in the informative phase [9,19,29]. Moreover, the bridge between the informative and earliest generative phases has been relatively neglected, and the specific experiences of product designers have not yet come to the fore. 2.2. Definition of the ‘‘psychological processes whereby design information is categorised’’ The bridge between the informative and earliest generative phases involves the generation of new ideas and new solutions. It begins with numerous mental images, memorised design briefs, and other information derived from previous design projects [8]. This process has been recognised as an individualised experience for designers that manifests in repetitive cognitive activities [28]. During the earliest generative phase, certain parts of the mental images can be externalised in sketches. These early sketches are not mature or suitable to be shared with or interpreted or used by other people. Instead, they can serve as external representations (i.e., externalised memories that act as visual tokens during later inspection) [15,25,36,43]. External representations (e.g., early sketches) allow a reflexive conversation between the designer and the product to be created [15,43]. Previous studies have shown that external representations allow designers to identify errors that are then used to generate new ideas [1]. Similarly Crilly et al. [15] noted that designers engaged in ‘‘bi-directional conversations’’ with representations insofar as intentions were formed and reformed during the activities of representation (see also Schön’s ‘‘Seeing–Drawing–Seeing model’’ [41]). External and internal information interact with each other in an evolutionary manner and are integrated and synthesised into categories contributing to design solutions via the designer’s mental processing [8]. In this respect, we define this phase as involving the psychological process whereby design information is categorised during the sketching that occurs in the earliest generative phase. More precisely, our aim is to identify the kind of cognitive operations that extract design information from memory and to determine how this design information is transformed or categorised during early sketching. Towards this goal, the following section proposes an initial descriptive model of information processing that integrates memory models derived from cognitive psychology, which describe the transfer of information through memory, including those of Atkinson and Shiffrin [2], Baddeley et al. [3], and Broadbent [11]. 2.3. Proposal of a descriptive model of information processing Broadbent [11] proposed a sequence of cognitive processing stages that can be performed in bottom-up or top-down order. Bottom-up processing is considered a stimulus-driven process caused by sensory stimuli, whereas top-down processing is seen as memory-driven. In many cases, stimulus-driven processes are based on inspiration such as photos, magazines, etc., which evoke feelings or emotions. Memory-driven processes are driven by knowledge derived from past experiences. In this paper, we focus particularly on memory-driven processes, which have received relatively less attention and thus remain less understood due to their implicit nature, characterised by information stored in memory as well as cognitive operations related to such information. We adapted two theoretical models drawn from cognitive psychology to formalise our examination: the model developed by Atkinson and Shiffrin [2] and that developed by Baddeley et al. [3] (see Fig. 2).We selected cognitive operations related to six phenomena to account for overall information processing: stimuli, perceptual action, questioning, association, transformation, and judgment/decision. More specifically, operations involving questioning, associating, and transforming play roles in retrieving memorised design information from long-termmemory (LTM) and moving it to working/short-term memory (WM/STM). According to the Geneplore Model defined by Finke et al. [21] in the work of Benami and Jin [5], several types of cognitive operations underpin the generative phase: retrieval of information from memory, association, mental synthesis, mental transformation, analogical transfer, and categorical reduction. Several of these, including mental synthesis and reduction, are difficult to categorically identify through verbalisations or sketches, but the remaining [(Fig._1)TD$FIG] Fig. 1. Research methodology: action research approach.