Sketching and creative discovery I M Verstijnen and J M Hennessey, Delft University of Technology, Faculty of Industrial Design Engineering, Jaffalaan 1, 2628 BX Delft, The Netherlands C van Leeuwen and R Hamel, University of Amsterdam, Department of Psychology, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands G Goldschmidt, Technion-Israel Institute of Technology, Faculty of Architecture and Town Planning, Technion Haifa, Israel 32000. In the search for helpful computer tools for sketching in the early phases of design, the approach was taken to experimentally study sketching behaviour. In two series of experiments two mental processes revealed themselves as essential in the creative process: Restructuring and Combining. These two processes are in turn influenced by expertise in sketching and individual creativity. In this article each of the factors: Combining, Restructuring, Expertise and Creativity, will be separately highlighted with respect to their impact on sketching behavior. Finally, on the basis of these results conclusions are drawn for computerized sketching aids. 1998 Elsevier Science Ltd. All rights reserved Keywords: drawing, sketching, creativity, design cognition, computer supported design O ne day, the story goes, Archimedes jumped out of the bath and ran joyfully and nakedly through the streets of Syracuse. Finally, he had discovered the solution to a problem which had been bothering him. For a long time, he had wondered how to measure the volume of an irregular object. Obviously, the discovery came to him at a moment he had not anticipated. This aspect of discovery is more frequently encountered in anecdotal evidence and self-reports. Friedrich von Kekulé reports drowsing in front of his fireplace when suddenly the solution, to a problem he had been working on, showed up. The image he saw in the flames about snakes biting their own tails hinted him to drop an assumption in organic chemistry, which prescribed that organic molecules must be strings of carbon atoms. This enabled him to come up with the idea of a ring structure for the benzene molecule. Kekulé’s discovery came to him in a state of reduced awareness, but this appears not to be the rule. Henri Poincaré was entering a bus which was 0142-694X/98 $—see front matter Design Studies 19 (1998) 519–546 PII: S0142-694X(98)00017-9 1998 Elsevier Science Ltd All rights reserved Printed in Great Britain DST: design studies (page 1 ) 08-10-98 10:42:42 Rev 14.02x 519 zdst$$140h to take him on a geological trip, when suddenly he saw a fundamental property, uniting a hitherto unrelated group of mathematical functions. These, and several other reports of scientific discoveries are frequently reported1–3. All the anecdotes on creative discovery have the unanticipated character of the discovery in common. 1 Dreistadt, R ‘The use of analogies and incubation in creative problem solving’ Journal of Psychology Vol 71 (1968) pp 159– 175 2 Miller, A I Imagery in scientific thought MIT Press, Cambridge, MA (1986) 3 Rothenberg, A The emerging goddess University of Chicago Press (1979) 4 Goldschmidt, G ‘Serial sketching: Visual problem solving in designing’ Cybernetics and Systems Vol 23 (1992) pp 191– 219 5 Hennessey, J M The IDEATE project: ‘Exploring computer enhancements for conceptualizing’, in Automation based creative design: Current issues in computers and architecture, T White and A Tzonis (eds) Elsevier Science, Amsterdam (1994) pp 349–362 6 Kolli, R and Hennessey, J M Deriving the functional requirements for a concept sketching device: A case study, Proceedings of Vienna conference on Human-Computer Interaction Springer Verlag (1993) pp 184– 195 7 Stuyver, R and Hennessey, J M A support tool for the conceptual phase of design, Proceedings of the Human-Computer Interaction Conference Cambridge University Press (1995) pp 235–245 8 Fish, J and Scrivener, S ‘Amplifying the mind’s eye: Sketching and visual cognition’ Leonardo Vol 23 No 1 (1990) pp 117–126 9 Verstijnen, I M, Stuyver, R, Hennessey, J M, van Leeuwen, C and Hamel, R Consideration for electronic idea-creation tools, Companion of CHI’96, Vancouver, Canada Addison Wesley (1996) pp 197–198 The unanticipated character of discovery makes it unlikely that these creative individuals had paper and pencil available to support the breakthrough in their thinking with sketching. In the light of this evidence, it may seem slightly audacious to suggest that sketching could have an important role in discovery. Yet, this is what is frequently reported by artists and designers, and what will be concluded from our studies. That externalization fulfils a need, is suggested by the fact that most artists and designers use some kind of externalization, e.g. sketching and clay modeling. They consider this essential for their creative process and will report frustration if hindered in doing so. Sometimes, people find their way around this frustration and this is why sketches can be found on backs of envelopes, edges of newspapers, or napkins. Designers have called sketches made in such a situation idea-sketches. In contrast to presentation-sketches, idea-sketches are made in the early phases of design. They function as a tool to interact with imagery4 and are predominantly for private use. Because of their early appearance in the design process, idea-sketching will have an important role in creative processes. This is the reason why many computer tools aim at supporting and improving idea-sketching. The IDEATE-project5–7 is one of the projects which acknowledges the beneficial aspects of computer tools for supporting idea-sketches. This project envisages the development of a tool, the IDEATOR. The IDEATOR will contain all facilities that are needed for storing sketches in memory, copying and pasting, displaying imported pictures or video’s on the sketch surface. But in addition, the IDEATOR may have to include a set of additional facilities, based on insight in the drive or motivation behind idea-sketches. In order to include such facilities, the drive or motivation behind ideasketches has to be studied more closely8,9. The unpredictability of ideasketching behavior is a challenge to such study. The private nature of these sketches, their proverbial appearance on the back of an envelope, the absorption of the sketcher in his or her activities, makes idea-sketching a fascinating topic, which has been an impetus, both for self-reflexive activi- 520 DST: design studies (page 2 Design Studies Vol 19 No 4 October 1998 ) 08-10-98 10:42:42 Rev 14.02x zdst$$140h 10 Garner, SW ‘Drawing and designing: the case for a reappraisal’ Art and Design Education Vol 9 No 1 (1990) pp 39–55 11 Goldschmidt, G Linkography: ‘Assessing design productivity’, in Cybernetics and Systems ’90, R Trappl (ed) World Scientific (1990) pp 291–298 12 Schenk, P ‘The role of drawing in the graphic design process’ Design Studies Vol 12 No 3 (1991) pp 168–181 13 Verstijnen, IM and Van Leeuwen, C ‘A book review of Imagery, creativity, and discovery: A cognitive perspective, B Roskos-Ewoldsen, M IntonsPeterson and R Anderson (eds) (North-Holland, Amsterdam 1993)’ Acta Psychologica Vol 89 (1995) pp 293–295 14 Anderson, R E and Helstrup, T ‘Multiple perspectives on discovery and creativity in mind and on paper’, in Imagery, creativity, and discovery: A cognitive perspective, B Roskos-Ewoldson, M J IntonsPeterson and R E Anderson (eds) Elsevier Science Publishers (1993) pp 223–253 15 Anderson, RE and Helstrup, T ‘Visual discovery in mind and on paper’ Memory and Cognition Vol 21 (1993) pp 283–293 16 Metcalfe, J ‘Feeling of knowing in memory and problem solving’ Journal of Experimental Psychology: Learning, Memory and Cognition Vol 12 (1986) pp 288–294 17 Metcalfe, J and Wiebe, D Intuition in insight and noninsight problem solving Memory and Cognition (1987) pp 238–246 18 Wallas, G The Art of Thought Harcourt Brace, New York (1926) 19 Hadamard, J The psychology of invention in the mathematical field Princeton University Press, Princeton, NJ (1945) 20 Koestler, A The Act of Creation London (1975) 21 Poincaré, H La science et méthode Flammarion, Paris (1908) 22 Solso, R L Cognitive psychology (3rd ed) Allyn and Bacon, Boston (1991) 23 Boden, M The creative mind: Myths and mechanisms Weidenfeld and Nicolson (1990) 24 Rothenberg, A and Hausman, C R The creativity question Duke University Press, Durham, NC (1976) ties of expert sketchers such as designers themselves, and for experimental studies by psychologists. 1 Sketching and mental imagery Until now, paper and pencil sketching has been discussed predominantly among those who are themselves actively engaged in sketching, such as industrial designers and architects. Their descriptions range from selfreports10 on the one hand, to objective descriptions of the sketch process4,11,12 on the other. This literature concentrates on the sketching activities themselves; the mental processes, from which the sketching behavior originates are still to be investigated. Psychologists have only recently touched upon this issue13. Anderson and Helstrup14,15 were the first within the information processing framework of psychology to systematically explore the field of idea sketching. Their seminal proposal was, that the decision to sketch is made when creative processing is met with resource limitations. In their experiments, however, they failed to obtain support for this view. This still leaves unexplained why idea-sketching could be useful. The question, why artists and designers need externalization for discovery in a creative process can be approached in a variety of ways. The most direct way appears to be the introspective way. Many artists and designers have studied their own creative processes and have launched a great variety of ideas about the how, what and why of sketching. This ranges from casual observations to systematic description10. Introspective methods formed in the 19th century are the basis for the scientific revolution that led to the study of mental processes in psychology. Many psychologists, however, have questioned the validity of introspection as the most objective way of studying mental processes. Objections to the use of this method have been raised in particular for the type of discoveries presently discussed. Metcalfe16,17 argues that the time period preceding such a discovery (the incubation period18–22) is not open to introspection. The wide variety and lack of systematicity in self-reports may reflect these problems. It is possible that these self-reports reflect whichever ideology the artist happens to believe. In an attempt to characterize these beliefs, Boden23 distinguished two types: inspirational beliefs, reflecting a Platonic notion of insight as the discovery of an eternal idea24, and romantic beliefs, stressing the uniqueness of artistic and scientific talents. The scorned method of introspection is not to be confused with another method which has been considered useful for the study of creative dis- Sketching and creative discovery DST: design studies (page 3 ) 521 08-10-98 10:42:42 Rev 14.02x zdst$$140h covery processes. This method collects and analyzes think-aloud protocols. Think-aloud protocols are self-reports which differ in an important way from introspection. A think-aloud protocol is collected during a process of creative discovery instead of afterwards. Therefore, the protocol is a direct verbalization of the ongoing process, in which self-reflexive expressions are discouraged. 25 Shepard, R N ‘Externalization of mental images and the act of creation’, in Visual learning, thinking and communication, B S Randhawa and W E Coffman (eds) Academic Press, NY (1978) pp 133–189 26 Ericsson, KA and Simon, HA ‘Verbal reports as data’ Psychological Review Vol 87 (1980) pp 215–251 27 Elshout, J and van Leeuwen, C ‘Protocolanalyse als Methode van Kennisacquisitie voor Expertsystemen (Protocol Analysis as Method for Knowledge Acquisition in Expert Systems)’, in Kennis in organisaties: Theorie en toepassing van kennissystemen, R Jorna and J Simons (eds) (Knowledge in organizations: Theory and applications of expert systems). Muiderberg, Coutinho (in dutch) (1992) 28 Brandimonte, M A, Hitch, G J and Gabbino, P Release from verbal overshadowing. Paper presented at the European Society for Cognitive Psychology Conference, Copenhagen, Sweden (1993 September) 29 Schooler, J W, Fallshore, M and Fiore, S M ‘Putting insight into perspective’, in The nature of insight, R J Sternberg and J E Davidson (eds) MIT Press, Cambridge, MA (1995) 30 Wilson, TD, Lisle, DJ, Schooler, JW, Hodges, SD, Klaaren, KJ and Lafleur, SJ ‘Introspection about reasons can reduce post-choice satisfaction’ Personality and Social Psychology Bulletin Vol 19 (1991) pp 331–339 This latter approach suffers from the fact that most creative processes extensively make use of visual thinking, or, in other words, there is a strong contribution of visual imagery. These processes are not accessible to direct verbalization. As Shepard25 put it: ‘... it seems reasonable that the most novel ideas and radical departures from traditional ways of thinking are not likely to arise within the very system of verbal communication that is the primary vehicle for maintaining and perpetuating established ideas and entrenched traditions’ (p. 156). Protocol analysis and introspection, therefore, are not appropriate to reveal this particular kind of processes26,27 and might even obstruct them28–30. The third way of approaching the question is the experimental method. This approach cannot easily address the problem directly, as creative processes are notoriously unpredictable19. For this reason, the experimental method attacks the question by inverting the problem. For instance, for the problem what sketching contributes to the creative process, instead of raising the question why sketching is useful, the question is raised, what limitations do the mental processes have that require sketching? This strategy is employed in the present study. The search for limitations in processing has been pioneered by Anderson and Helstrup14,15. They proposed resource limitations to be the decisive impetus for sketching. Resource limitations, for example, are encountered when memory fails to keep track of a growing information load. In their experiments, however, these authors failed to obtain support for a crucial role of resource limitations in sketching. An alternative approach has been taken in the present study. This approach rests on the idea that, since imagery plays an important role in the creative process, the limitations are to be found in imagery. In this view, the mental operations leading to discovery are viewed as a set of operations on a mental image. Sketching is needed if the operations cannot be done within mental imagery alone, or if the operations are much easier to perform externally. This approach draws the attention away from the externalization itself and focuses on the mental processes preceding the sketching activity. Once 522 DST: design studies (page 4 Design Studies Vol 19 No 4 October 1998 ) 08-10-98 10:42:42 Rev 14.02x zdst$$140h these processes are understood, this will lead to insight in the origin and function of externalization. The psychological literature on discovery in mental imagery has studied several different mental imagery processes. Some of these are easy and frequent; others are difficult and rare. The latter type being candidates for externalization support. The fact that some processes in mental imagery were found to be difficult and others were easy, has led to a controversy in the literature before it was realized that two different types of processes may exist. Opposing conclusions were drawn on the one hand by Chambers and Reisberg31, and Reed32 and on the other hand by Finke and Slayton33. 31 Chambers, D and Reisberg, D ‘Can mental images be ambiguous?’ Journal of Experimental Psychology: Human Perception and Performance Vol 11 (1985) pp 317–328 32 Reed, SK ‘Structural descriptions and the limitation of visual images’ Memory and Cognition Vol 2 (1974) pp 329–336 33 Finke, RA and Slayton, K ‘Explorations of creative visual synthesis in mental imagery’ Memory and Cognition Vol 16 No 3 (1988) pp 252–257 34 Hyman, I E and Neisser, U Reconstruing mental images: Problems of method Emory Cognition Report, #19, Emory University, Atlanta, GA (1991) 35 Peterson, M, Kihlstrom, J, Rose, P and Glisky, M ‘Mental images can be ambiguous: Parts, wholes, and strategies’ Memory and Cognition Vol 20 (1992) pp 107–223 36 Reed, SK and Johnsen, JA ‘Detection of parts in patterns and images’ Memory and Cognition Vol 3 (1975) pp 569–575 Chambers and Reisberg showed in their experiments that subjects were unable to reverse the interpretation of an ambiguous figure (e.g. chef/dog, see Figure 1.) in mental imagery. That is, when the figure was presented to the subjects as representing a dog, they were unable to discover the alternative interpretation of a chef before their mental eye, while, on the other hand, this discovery took place easily when subjects were allowed to visually inspect the figure. Subsequent investigations34,35 with a similar paradigm did not find completely zero performance, but discovery performances remained strikingly low. Reversal involves the discovery of an unanticipated structure. Chambers and Reisberg’s results, therefore, argue for limitations on discovery in mental imagery, as compared to visual perception, and hence for a major role for sketching in discovery. Similar restrictions on mental imagery were obtained by Reed and Johnsen36. They showed that the extraction of an unanticipated novel component is difficult in imagery, as compared to visual perception. These authors used a part-whole detection task (see Figure 2). In this task, a composite figure is presented, followed by another one. The subject of the experiment must decide if the second is contained as a part of the first. Percentages of correct answers and reaction times reflect the accuracy of processing. Figure 1 An example of an ambiguous figure. The figure could be interpreted either as a dog or as a chef, and was used as stimulus by Chambers and Reisberg31 to show that reversal in mental imagery meets considerable difficulties Sketching and creative discovery DST: design studies (page 5 ) 523 08-10-98 10:42:43 Rev 14.02x zdst$$140h Figure 2 An example of a configuration and several alternative interpretations of its components. Reed and Johnsen36 showed that when the configration is remembered as two overlapping triangles (A) an alternative composition (B to D) is very difficult to reveal in mental imagery With these tasks, it can be shown for perception that certain parts are more easily perceived and remembered as components of the whole than others. This depends on which parts are seen as building blocks of the structure of the whole. Usually, a whole is perceived as a unique composition of parts, this, although it is possible in principle to see the whole as composed in several alternative ways as well (see Figure 2 on the right). Reed and Johnsen showed that an alternative composition was not recognized in mental imagery. Chambers and Reisberg used a task, which involved imposing a new structure on old components of a figure. Reed and Johnsen involved the identification of new components in a structure. Both experiments, therefore, involve conditions in which subjects start from a given, structured pattern. The task requires them to break up this structure. From these experiments, the hypothesis can be drawn that mental imagery faces considerable difficulty in restructuring the initial conception of a pattern, and hence to discover new information in a mental image. Opposite conclusions on the issue of discovery in mental imagery were reported by Finke33,37. These authors asked subjects to synthesize simple elements into a recognizable object before their inner eye. For example, a letter ‘J’ and a letter ‘D’ can form an umbrella. They found that subjects were able to create and discover new unanticipated objects. 37 Finke, R A Creative Imagery: Discoveries and inventions in visualization Erlbaum, Hillsdale, NJ (1990) It could be observed, however, that Finke’s task does not require restructuring. The structure of the elements as initially given remains intact. In the 524 DST: design studies (page 6 Design Studies Vol 19 No 4 October 1998 ) 08-10-98 10:42:43 Rev 14.02x zdst$$140h umbrella example this means that the component structure of each letter ‘J’ and ‘D’ is not violated. Therefore, the processes involved in Finke’s Figural Combination Tasks differ essentially from those involving restructuring. The processes observed by Finke, which are easily performed in mental imagery, are processes of combining. Therefore the opposing conclusions from the mental imagery literature can be reconciled on the assumption that two forms of processing in imagery have to be distinguished, viz. restructuring and combining. The two different experimental paradigms, familiar from the literature, involve restructuring and combining processes to different degrees. If the processes of combining and restructuring impose different loads on mental imagery, different effects of paper-and-pencil support can be expected. If the mental imagery task is easy, as in the Figural Combination Task (Finke), minor effects are expected. If the mental imagery task is difficult because of restructuring, sketching is expected to enhance performance in the Component Detection Task (Reed). In two series of experiments this hypothesis was tested. The first series used a Component Detection Task38. The second series used a Figural Combination Task39. Each series will be discussed separately in the following sections with their associated theoretical processing characteristics (restructuring or combining). Expertise and creativity were shown to have differential impact on these two processes. Therefore, the relation of sketching to each of the factors: restructuring, combining, expertise and creativity, will be highlighted in separate sections. 2 38 Verstijnen, I M, van Leeuwen, C, Hamel, R and Hennessey, J M What imagery can’t do and why sketching might help (submitted-a) 39 Verstijnen, I M, Goldschmidt, G, van Leeuwen, C, Hamel, R and Hennessey, J M Discovery in imagery; synthesis can be done but analysis takes a sketch (submitted-b) Sketching and restructuring In this section and the following one on sketching and combining, only the results of expert sketchers are considered, results concerning novice sketchers will be dealt with in the section on sketching and expertise. The experts in the experiments were all industrial design engineering students having had at least two years of drawing education. The term ‘experts’ is used to stress the difference with ‘novices’, but is not meant to be interpreted as designating highly experienced sketchers. Vice versa, the novices, drawn from a population of first year undergraduate psychology students, are not expected to lack drawing skills completely. A comparison between novices and experts can be found in the section on sketching and expertise. 2.1 Restructuring in the component detection paradigm The first series of experiments was inspired on the work of Reed32,36 These experiments were performed with overlapping forms of which a novel Sketching and creative discovery DST: design studies (page 7 ) 525 08-10-98 10:42:43 Rev 14.02x zdst$$140h component had to be extracted. For this reason, the task was called a Component Detection Task. Prior to the experiment, subjects were informed about a set of components used. These were simple 2D wire-frame elements (e.g. square and diamond). During the experiment, configurations of overlapping components were presented, one at a time. Each configuration was briefly presented to the subjects. The short presentation time ensured that people were not able to grasp more information from the configuration than the identity of the components and their relative position. Hence, Figure 3 will be remembered as slanted square, and diamond with their lower edges aligned40. The task was to answer the question whether the configuration contains a subsequently presented figure, as a part. Some of these figures were indeed contained as parts in the configuration and others were not (the false parts). Among the parts, a distinction was made between existing ones, which were components from which the figure was constructed, and novel ones, which were not used in the construction but resulted from the overlap between two or more components (see Figure 3). 40 Clark, HH and Chase, WG ‘On the process of comparing sentences against pictures’ Cognitive Psychology Vol 3 (1972) pp 472–517 The difference between novel and existing parts is relevant to the issue of restructuring. Existing parts can be extracted from the configuration without restructuring, however, restructuring is to be performed if an novel part is to be detected. This is the case, because the configuration is remembered as a combination of the original components. Restructuring was therefore measured by the percentage correct on novel parts. The percentage correct of existing parts serves as a baseline, to determine the accuracy of performance without restructuring. Three variations of this experimental paradigm were administered; the first compared a group of subjects compelled to sketch with a group which was Figure 3 An example of a configuration used in the Component Detection Task. Detection of novel parts requires restructuring, because this figure will be remembered as a configuration consisting of a square and a diamond. No restructuring is necessary to discover the existing part 526 DST: design studies (page 8 Design Studies Vol 19 No 4 October 1998 ) 08-10-98 10:42:43 Rev 14.02x zdst$$140h denied this strategy; the second experiment registered spontaneous sketch behavior; in the third the number of elements in a configuration were varied. A spontaneous sketching experiment approaches more closely the circumstances in which people normally turn to sketch. The first experiment with this paradigm, allowed half the group of subjects to sketch (the with-sketch condition), and denied this strategy to the other half (the without-sketch condition). Figure 4 shows the results for both groups. Subjects who were allowed to sketch performed significantly better on restructuring, i.e. finding novel parts, than their counterparts in the condition where sketching was not allowed. The latter performed no better than chance-level (i.e. 50%). 41 Jacoby, L and Dallas, M ‘On the relationship between autobiographical memory and perceptual learning’ Journal of Experimental Psychology: General Vol 3 (1981) pp 306–340 42 Jacoby, L The relationship between learning and recollection: Memory attributes vs. Memory attributions Paper presented at the Annual Meeting of the Psychonomic Society, Boston, Mass (1985) Figure 4 Percentages rect detection of These findings contrast with those for existing parts, see Figure 5. On existing parts both the without-and the with-sketch group scored equally well. Although a slight surplus on existing parts can be noted for the withsketch group with respect to the without-sketch group, this difference is not significant. This surplus, which was noted for both experts and novices, could be explained on the basis of false parts only. Sketching in the case of false parts could have been helpful to inform the sketcher on whether he/she forgot this particular part or on whether it did not form an element of the configuration, and thus was indeed a false part. Sketching in this case performed a similar role as reported in the Jacoby and Dallas41,42 studies, in which they showed that previously learned, but forgotten, words look more familiar. cornovel components on the Component Detection Task. Subjects not allowed to sketch (without-sketch condition) act on chance level (50%), whereas subjects compelled to sketch (with-sketch condition) raised their performance to a level significantly above chance Sketching and creative discovery DST: design studies (page 9 ) 527 08-10-98 10:42:43 Rev 14.02x zdst$$140h Figure 5 With- and without sketch conditions in the Component Detection Task do not differ on parts not requiring restructuring, i.e. existing parts Figure 6 illustrates the scores of the with-sketch group on novel and existing parts. Although a difference exists, this difference is not significant, and illustrates that performance on novel parts can be raised to the level of performance on existing parts with the aid of sketching. This is in contrast with the without-sketch group. Figure 6 Expert sketchers are able to raise their performance on novel parts in the Component Detection Task to the level of existing parts 528 DST: design studies (page 10 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:43 Rev 14.02x zdst$$140h Similar phenomena were observed when spontaneous sketching was compared to compelled sketching. Performance on novel parts was significantly improved by spontaneous sketching (a significant correlation of r = 0.715), whereas sketching did not improve performance on existing parts (r = ⫺0.034). In the compelled sketching experiment, therefore, it was concluded that people cannot distinguish an novel part from a nonpart when not allowed to sketch. The same could be concluded from the spontaneous-sketching experiments. Equal numbers of subjects turned to sketch spontaneously on novel parts as on false parts. This result demonstrates that prior to sketching, people barely have an idea of the occurrence of an novel part. To investigate individual correlates of the restructuring ability, various tests were administered in the spontaneous sketch experiment: the Raven43 progressive matrices test, measuring intelligence, Witkin’s44 embedded figures test, Mark’s45 vividness of visual imagery questionnaire (VVIQ), Kunzendorf’s46 aesthetic preference test, measuring creativity, and a measure of short-term memory-span. 43 Raven, J C Advanced Progressive Matrices Set II (1988). 44 Witkin, H A, Oltman, P K, Raskin, E and Karp, S A A manual for the embedded figures tests Consulting Psychologists Press (1971) 45 Marks, DF ‘Visual imagery differences in the recall of pictures’ British Journal of Psychology Vol 64 (1973) pp 17–24 46 Kunzendorf, RG ‘Mental images, appreciation of grammatical patterns, and creativity’ Journal of Mental Imagery Vol 6 No 1 (1982) pp 183–201 47 Chara, PJ and Hamm, DA ‘An inquiry into the construct validity of the Vividness of Visual Imagery Questionnaire’ Perceptual and Motor Skills Vol 69 (1989) pp 127–136 48 Reisberg, D and Heuer, F ‘Vividness, vagueness and the quantification of visualizing’ Journal of Mental Imagery Vol 12 No 3 and 4 (1988) pp 89–102 49 Morris, P and Hampson, P Imagery and consciousness Academic Press, New York (1983) Restructuring (novel part detection) correlated with intelligence, and creativity (this latter correlation will be dealt with in the section on restructuring and creativity). Accuracy of performance without restructuring (existing part detection) correlated with intelligence, memory span, and embedded-figure detection. Vividness of imagery, as measured with Mark’s VVIQ, did not correlate with any of the variables. This result can be attributed to the lack of validity in measures of vividness47,48. It may also be the case that vividness of imagery is more important for inspection of imagery than for manipulation and transformation of images49. Factor Analysis on the above correlations showed that intelligence, shortterm memory span, embedded-figure detection and the experimental measure of accuracy-without-restructuring (existing parts) are associated measures. The abundant representation of ‘smart’ variables in this factor, led to its name: the Smart Factor. Amount of sketching on novel and existing parts, creativity, and the experimental measure of restructuring (novel part detection) formed a second, independent set of associated measures. This factor was called the Art Factor, because of the occurrence of ‘arty’ variables. The Art Factor was shown to be about 5 times as important for restructuring than the Smart Factor39. One of the constituents of the Smart Factor is memory capacity. The fact that the Smart Factor contributes only little to restructuring, suggests that Sketching and creative discovery DST: design studies (page 11 ) 529 08-10-98 10:42:43 Rev 14.02x zdst$$140h memory capacity is not a relevant determinant of the difficulty of restructuring in mental imagery and therefore irrelevant for the motivation to sketch. This finding contradicts the intuitive idea that limitations in shortterm memory trigger sketching behavior50. To perform a more rigid test on this idea, a third experiment was performed, that focused on memory. In this experiment, the number of elements of a configuration was varied. If short-term memory-span is irrelevant for sketching behavior, then, it was hypothesized, no change in performance is expected when the number of components in a configuration is raised51. Moreover, if novel parts are used, the accuracy of detection will not depend on the number of components. Whether two or five components were presented, the number of spontaneous sketches was unaffected by the number of components. Also, accuracy of performance was independent of the number of components. It was, therefore, concluded that memory limitations are irrelevant for sketching behavior. Many artists and designers, when asked for their motivation, ascribe a function of memory extension to their sketching behavior. The results of the present experiments contradict these introspective reports, instead they confirm the conclusion of the previous experiment, that memory restrictions do not form the motivation for sketching. It cannot be excluded, however, that sketches may fulfil a role for retention on a longer term than the scope of the present experiments52. In general, however, it may be concluded for the Component Detection Task, that the extraction of novel components yields the decisive impetus for sketching, because this form of restructuring is difficult to perform in mental imagery. 2.2 50 Ullman, DG, Wood, S and Craig, D ‘The importance of drawing in the mechanical design process’ Comput. and Graphics Vol 14 No 2 (1990) pp 263–274 51 Cavanagh, JP ‘Relation between the immediate memory span and the memory search rate’ Psychological Review Vol 79 No 6 (1972) pp 525–530 52 Reisberg, D ‘External representations and the advantages of externalizing one’s thoughts’, in The ninth annual conference of the cognitive society, E Hunt (ed) Erlbaum, Hillsdale, NJ (1985) pp 281–293 Restructuring in the figural combination paradigm The second series of experiments used a modified version of Finke and Slayton’s figural combination paradigm. Before the experiment started, six possible components (cone, cube, cylinder, sphere, diamond, flat-square) were presented. Subjects were instructed to memorize them in combination with their names. During the experiment only the names of three components were presented at a time. Each time this occurred, subjects had to combine in mental imagery three simple components into an object. Half of the subjects were allowed to sketch during the mental imagery phase, the other half was denied this strategy. The resulting objects were drawn on a separate sheet of paper and rated on creativity, originality and practicality by independent judges. The rated creativity of the end-products of with-sketch and without-sketch conditions was compared. It turned out that the creativity of the end-products was independent of strategy. This result was in accordance with the earlier conclusion by And- 530 DST: design studies (page 12 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:43 Rev 14.02x zdst$$140h erson and Helstrup14,15, who observed that discovery in mental imagery was easy and frequent. According to the hypothesis, the reason is that the Figural Combination Task is predominantly a combining task. Nevertheless, an investigation of whether restructuring occurred as well as performed. For this purpose, in addition to the ratings, the objects were also scored on other properties. For example, when a cube was one of the components presented, it was regularly found to be transformed into a rectangular box. In Figure 7 (on the right side) the diamond which originally was presented as having a squared cross-section is transformed into one with a triangle as cross section. These kinds of transformations were considered to reflect restructuring. Various kinds of these component transformations were scored. From those transformations, a restructuring measure was computed. The restructuring measure reflects the amount of structural transformations performed on the components. Individual subjects were scored on this measure. An other example of restructuring in the figural combination paradigm shows in the occurrence of junctions between components. It may require restructuring to form complex junctions between combined objects. Complex junctions are defined as those junctions, which require transformations of the components, in order to perform a fit; if one component has to fit to another, it is sometimes needed to perform a transformation of the components. For that reason, complex junctions are indicative of restructuring. Interestingly, in the without-sketch conditions, the number of complex junctions of 3D differed not from that in the with-sketch conditions, when averaged across all situations. This measure, however, included complex- Figure 7 Two examples of objects created in the figural combination experiments. The figure on the left is a shower for a swimmingpool. The ball has to be pushed up to get a shower. This being hard, the shower will save water. On the right is a tool created for windowcleaners. It can be suctioned to the wall, and be used as a grip or a foot-rest Sketching and creative discovery DST: design studies (page 13 ) 531 08-10-98 10:42:43 Rev 14.02x zdst$$140h junctions hidden in the back of the object. When only visible complex junctions were considered, their number in the with-sketch condition was significantly above that of the without-sketch condition. It may be concluded that the subjects in the without-sketch condition reach equally creative end-products, because they have a way around restructuring, such as turning the complex junction to the back, when denied the possibility to sketch. The mean restructuring score for the with-sketch group was significantly higher than that of the without-sketch group (see Figure 8a: a restructuring score of for example 2 denotes that for each subject the created objects had an average of two restructurings of whatever type per object). Thus, even though the products were equally creative, they were achieved by the without-sketch and with-sketch groups in different ways: sketching subjects make use of restructuring strategies more frequently than non-sketching subjects. When Finke’s original set of 2D elements (e.g. square, triangle, circle) was used similar results for restructuring were found (see Figure 8b.) The method to score restructuring in the present task differs from that of the Component Detection Task. In order to confirm that both tasks measure the same ability, it could be considered useful to compare individual scores across the experiments. Eleven subjects took part in the with-sketch groups of both the Component Detection Task and the Figural Combination Task. This made a check for the validity of the restructuring measure in the Figural Combination Task possible. A correlation was calculated between subjects’ score on novel parts in the Component Detection Task and their restructuring score in the Figural Combination Task. A highly significant correlation was found. The correlation shows that restructuring is a personal characteristic, which is consistent over tasks and stable over time. This is an argument in favor of the validity of the measures of restructuring in the two series of experiments and, in general, for the validity of the construct of restructuring. 53 Hinton, GE and Parsons, LM ‘Scene-based and viewercentered representations for comparing shapes’ Cognition Vol 30 No 1 (1988) pp 1–35 54 Pylyshyn, Z ‘What the mind’s eye tells the mind’s brain: A critique of mental imagery’ Psychological Bulletin Vol 80 (1973) pp 1–24 55 Pylyshyn, Z ‘The imagery debate: Analogue media versus tacit knowledge’ Psychological Review Vol 88 No 1 (1981) pp 16–45 Based on the combined results of both series of experiments, it can be concluded that mental images are not inspectable in the same ways as pictures53–55. The inability to perform restructuring in mental imagery constitutes a major factor in the usefulness of sketching. Not only severe restructuring, such as novel decomposition, is supported by sketching, also lighter forms of restructuring, such as occurred in the Figural Combination Task, are improved by externalization. When mental images are projected in sketches, new structures can be seen in the sketches which could not be obtained from the mental images before the projection. 532 DST: design studies (page 14 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:43 Rev 14.02x zdst$$140h 3 Sketching and combining In contrast to Finke’s original version of the Figural Combination Task, the one used in the current experiment was especially designed to test the influence of sketching on combining. Combining is reflected in the figural combination paradigm in the alignment of components of an object. Various forms of alignment are possible. For example, an object could have been created by a simple stacking of the components (Figure 7 on the Figure 8 Restructuring scores of the Figural Combination Task as a function of whether the subjects were not allowed to sketch or were compelled to do so in conditions using 2D or 3D components. In both the 2D and 3D task, expertized sketchers are able to raise their performance when allowed to sketch Sketching and creative discovery DST: design studies (page 15 ) 533 08-10-98 10:42:43 Rev 14.02x zdst$$140h left) or one component could have been aligned horizontally and another vertically (see Figure 7 on the right). Since each subject created multiple objects, different forms of alignment used by a subject could be scored. This score was considered to reflect the capacity to generate variety by combining. This score was therefore considered a subject’s combining score. According to this measure, subjects in the without-sketch condition of the 3D task performed equal to those in the with-sketch condition (Figure 9; a combining score for example 4 means that a subject applied four different forms of alignment). 56 Finke, RA and Kosslyn, SM ‘Mental imagery acuity in the peripheral visual field’ Journal of Experimental Psychology, Human Perception and Performance Vol 6 (1980) pp 126–139 57 Finke, RA and Kurtzman, H ‘Mapping the visual field in mental imagery’ Journal of Experimental Psychology: General Vol 110 (1981) pp 501–517 58 Pinker, S and Finke, R ‘Emergent two dimensional patterns in images in depth’ Quarterly Journal of Experimental Psychology Vol 29 (1980) pp 117–133 59 Richardson, J T E Mental imagery and human memory St. Martin’s Press, New York (1980) 60 Spearman, C Creative mind Appleton, New York (1931) A slightly different combining measure was used for the 2D version of the task. This measure, which was adopted from Anderson and Helstrup14,15 scored whether components were aligned in different orientations than initially presented. This measure was considered also to reflect combining, because this transformation leaves the component structure intact (therefore, no restructuring is involved) and the orientation of the components is prescribed by the configuration. On this measure, the sketching significantly deteriorated performance (Figure 10). On two different measures, equal or even deteriorated performances was reached as a result of sketching. This signifies that mental imagery is thoroughly capable of combining. Combining thus appears to be easy in mental imagery, and new information can be glanced effortlessly from a combined product, as was to be expected on the basis of experiments by Finke56–60. Or, as Spearman60 put it in his Principle of Relations: ‘When two or more Figure 9 Results of the 3D version of the Figural Combination Task: performance on a combining measure for the without-sketch and withsketch condition 534 DST: design studies (page 16 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:43 Rev 14.02x zdst$$140h Figure 10 Results of the 2D version of the Figural Combination Task: performance on a combining measure for the without-sketch and withsketch condition items (percepts or ideas) are given, a person may perceive them to be related in various ways’ (in Brown61). It can be concluded that no additional value is obtained from sketching if combining is to be performed. The fact that sketching can even deteriorate performance, as was the case in the 2D task, suggests that being compelled to sketch in conditions where it is not necessary will only distract the subject. 4 Sketching and expertise In the previous sections the results of expert sketchers (design students with at least two years of sketching experience) were described. However, in the majority of experiments they were compared to novice sketchers (psychology students with little sketching experience). 4.1 61 Brown, R T ‘Creativity: what are we to measure?’, in Handbook of creativity: Perspectives on individual differences, J A Glover, R R Ronning and C R Reynolds (eds) Plenum Press, New York (1989) pp 3–32 Expertise in the component detection paradigm Only one major difference was obtained between experts and novices in the experiment with compelled sketching. On novel parts in the with-sketch condition, novices performed significantly worse than experts (see Figure 11). In all other conditions, performance was equal. Sketching has helped experts in performing restructuring for the purpose of detecting a novel component, but it failed to do so for novices, although also for novices a slight increase was noted. In an attempt to answer the question why sketching is not as helpful for novices as for experts, it is of importance that the difference could not Sketching and creative discovery DST: design studies (page 17 ) 535 08-10-98 10:42:43 Rev 14.02x zdst$$140h Figure 11 Novices expert sketchers and perform equally on novel part detection when they are not allowed to sketch, in the with-sketch condition, experts outperform the novices be attributed to a worse performance on, for instance, remembering the components of the configuration. Such a difference would have led to different scores on the existing parts, which was not obtained, as Figure 12 clearly shows. On each and every single test, the novices test scores matched those of the experts. Therefore the difference between novices and expert sketchers cannot be explained by individual differences in ability, as measured by one of the various tests administered (intelligence, creativity, vividness of mental imagery, etc.). So neither the experimental scores, nor test scores provided a cue for the origin of the effect. For this reason, individual abilities, other than those relating directly to sketching, cannot explain the differential effect of sketching for experts and novices. An explanation is suggested, however, from a factor analysis, the same one as performed with the experts’ scores (see the section on Sketching and Restructuring: Restructuring in the Component Detection Paradigm). This analysis, when applied to novices, provided the same grouping of variables into a Smart and an Art factor. However, one notable exception was found. In contrast with the experts, for the novices, virtually no influence was obtained for neither the Art nor the Smart Factor on novel part discovery. Discovery of novel parts was identified in previous sections as a restructuring measure. This suggests, that the lower scores of novices in 536 DST: design studies (page 18 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:44 Rev 14.02x zdst$$140h Figure 12 On existing parts both the with-and without sketch group for both the novices and experts have matching performances the sketching condition for novel parts, were due only to their inability to perform restructuring with the aid of sketches. Differences in drawing skills may explain the novices’ inability to use sketches for restructuring. Expert and novice sketches differ sufficiently in appearance to warrant this conclusion: several industrial designers were able to reliably sort the sketches into expert and novice ones. A mean percent correct of 70% was obtained, suggesting that expertise can be seen in the sketches. 4.2 Expertise in the figural combination paradigm Novices took part in the 3D version of the figural combination paradigm only. As in the Component Detection Task, the novices scored lower than the experts on the restructuring measure in the with-sketch condition of the Figural Combination Task, see Figure 13. In fact, novices even showed an opposite trend. The ability to restructure therefore seems to differentiate between experts and novices, and this argues for restructuring to be a fundamental constituent of expertise. The combining measure did not differentiate between experts and novices. Although in both the without-sketch and the with-sketch conditions the novices scored lower than the experts, these differences did not reach significance, see Figure 14 (note that the scale has changed; it now reflects Sketching and creative discovery DST: design studies (page 19 ) 537 08-10-98 10:42:44 Rev 14.02x zdst$$140h Figure 13 In the Figural Combination Task in the without-sketch group matching performances on restructuring were found for the novices and experts, but in the with-sketch group the novices are outperformed by the experts Figure 14 On the combining score in the Figural Combination Task, all mean performances match. It made no difference whether subjects were allowed to sketch, nor when they were expert sketchers 538 DST: design studies (page 20 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:44 Rev 14.02x zdst$$140h the combining score divided by the number of objects per subject. This manipulation was necessary because of comparison between novices and experts). The equal performances of both groups on the combining measure indicate that the expertise in sketching does not reside in the ability to combine. The fact that restructuring did differentiate between experts and novices in the with-sketch condition but not in the without-sketch condition, supports the claim that the distinctive ability of experts with respect to novices resides in performing restructural transformations with the aid of sketches. The ability to combine, however, was equal for experts and novices. 5 Sketching and creativity Since only expert sketchers benefit from externalization of images, this section returns to the achievements of expert sketchers, in order to study the relation between sketching and creativity. 5.1 Creativity in the component detection paradigm In the component detection experiments, the Kunzendorf test of Aesthetic Preference46, measures the mastery of ‘visual grammar’. Creative individuals, according to Kunzendorf, have a better mastery of ‘visual grammar’, which improves their ability to transform and restructure knowledge. It turned out that people who scored high on this test were far more likely to find a novel part if they had spontaneously sketched, than the low scorers (a significant correlation of r = 0.654 was established, see Figure 15). This finding affirms the relationship between restructuring and creativity. Figure 15 The found correlation between creativity scores and rate of correct novel part detection when a spontaneous sketch had taken place Sketching and creative discovery DST: design studies (page 21 ) 539 08-10-98 10:42:44 Rev 14.02x zdst$$140h 62 Wallace, D B ‘Giftedness and the instruction of a meaningful life’, in The gifted and the talented: Developmental perspectives, F D Horowitz and M O’Brien (eds) American Psychological Association, Washington, DC (1985) 63 Cropley, A J ‘Improving intelligence by fostering creativity in everyday settings’, in Intelligence: Recapitalization and measurement, H A H Riwe Lawrence Erlbaum, Hillsdale, NJ (1991) 64 Guilford, J P The nature of human intelligence McGraw-Hill series in psychology, NY (1967) 65 Sternberg, J R Intelligence, information processing and analogical reasoning: The componential analysis of human abilities Lawrence Erlbaum, Hillsdale, NJ (1977) 66 Hennessey, B A and Amabile, T M ‘The role of the environment in creativity’, in The nature of creativity, R J Sternberg (ed) Cambridge University Press (1988) 67 Amabile, TM ‘Children’s artistic creativity: Detrimental effects of competition in a field setting’ Personality and Social Psychology Bulletin Vol 8 (1982) pp 573–578 68 Amabile, TM ‘Social psychology of creativity: A consensual assessment technique’ Journal of Personality and Social Psychology Vol 43 (1982) pp 997–1013 Restructuring, creativity, and sketching were found to constitute the Art factor. The finding of Art and Smart as two separate dimensions is in accordance with Wallace62 notion of ‘mental power’ or ‘extraordinariness’, which includes creativity and intelligence as separate factors63. Taken at face value, the independence of Art and Smart factors contradicts Guilford’s64, and Sternberg’s65 idea that creativity is an aspect of intelligence. The Art factor, however, comprises restructuring, but not combining. Guilford’s divergent thinking aspect stresses the combining aspect of creativity. 5.2 Creativity in the figural combination paradigm The relation between combining and creativity was studied in the figural combination paradigm. The objects combined by the subjects were rated on creativity by independent expert judges (design teachers). Their ratings correlated highly among each other, in contrast to those of novice judges. This finding is in accordance with Amabile’s66–68 operational definition of creativity, ‘A product or idea is creative to the extent that expert observers agree it is creative’. For this reason, the expert ratings were considered a valid indication of object creativity. The creativity ratings correlated significantly with both the combining score (a correlation of r = 0.482) and restructuring score (r = 0.534) in the figural combination paradigm (only objects in the 3D variant were rated), see respectively Figures 16 and 17. Figure 16 The relationship between subject’s combining score in the Figural Combination Task with their objects’ mean creativity rating. For the with-sketch group only 540 DST: design studies (page 22 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:44 Rev 14.02x zdst$$140h Figure 17 The relationship between subject’s restructuring score in the Figural Combination Task with their objects’ mean creativity rating. For the with-sketch group only On the basis of combining and restructuring scores, almost 70% of the variance in the creativity ratings in the sketch condition can be explained. The amount of explained variance provides an argument for the important role of combining and restructuring in creative discovery in the figural combination paradigm. These findings contrast with the view expressed by Hennessey and Amabile66 that ‘There is one basic form of creativity, one basic quality that observers are responding to when they label something ‘creative’.’ (p. 15). Creativity, instead, seems to have at least two constituents; restructuring and combining. Despite the fact that these two processes can explain as much as 70% of the variance in a single task and appear to have construct validity across tasks, the creative process will consist of more processes than the ones presently identified. For example, in the experiments discussed, the components for combining or restructuring were selected by the experimenter. This was necessary for experimental control on these processes. Outside the laboratory, the selection will be left to the creative individual. Individual preferences and differences in ability with respect to the selection of components for mental transformation will certainly constitute another important aspect of creativity which, however, is beyond the scope of the present sketching study. 6 General conclusions The distinction of combining and restructuring throws new light on the issue of sketching. The combining process is easy to perform in mental Sketching and creative discovery DST: design studies (page 23 ) 541 08-10-98 10:42:44 Rev 14.02x zdst$$140h imagery and is not supported by sketching. The restructuring process is difficult to perform in mental imagery and is enhanced by sketching. That restructuring is the difficult part, is confirmed by the fact that only experts are aided in performing it by sketching. The two processes of combining and restructuring together constitute important elements of the creative process (see Figure 18). From the result of these studies, it is possible to provide recommendations for the construction of computer tools for sketching. In general, such tools must, like paper and pencil, be intuitive; i.e. the requirements for their use may not exceed the current level of expertise of their users. Paper and pencil are used spontaneously by both experts and novices, which implies that these tools must have a low threshold of accessibility and their use may not require specialized knowledge if they are to replace paper and pencil. Since the combining process can be easily and rapidly performed before the mental eye, only the end-product of this process is likely to be found externalized. Combining itself is, according to the model, never an objective for externalization, and therefore will occur only in sketches intended to support the restructuring process. Combining objects on a computer tool, therefore, must preferably pass effortlessly and super fast. In addition, however, such tools must be helpful in excess of paper and pencil tools. The present studies suggest that appropriate support given to users, will have to allow users to raise their performance on the aspect of the task which is most difficult to perform, viz. restructuring. In the restructuring process, the sketcher draws one particular structure but does so in order to pick up novel structural components from perception of the sketch. Paper-and-pencil sketches are often unspecified and vague, allowing for perceptual creativity to flesh out a new structure. So a computer tool has Figure 18 The resulting model for the role of combining, restructuring and sketching in creative discovery process 542 DST: design studies (page 24 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:44 Rev 14.02x zdst$$140h either to support unspecified forms as input, or a flexible switching between various structural descriptions of the input after its creation. Kolli and Stuyver (reported in Hennessey5) studied the 3D CAD programs Pro-Engineer, Intergraph-EMS, Sculpt 3D and GIG3DGO. The first phase of this study revealed that with these state-of-the-art programs even a simple combining task with simple components is met with ample difficulty. Most programs required considerable time for the alignment of components. Combining, therefore, did not proceed as effortlessly and fast as was required for these programs to be called intuitive. In the second phase of this study, the subjects had to perform restructuring on the components of the previously combined objects. How the components had to be restructured during this phase was not known beforehand to the subjects in the first phase. It turned out that some subjects had chosen a form of combining that did not allow any alteration of the components in the second phase. Therefore, they had to combine the object again before they were able to restructure it. This latter result indicates that restructuring is a cumbersome job with current 3D CAD programs. These programs, therefore, failed to meet the requirement of being helpful as tools for ideageneration sketching in the early creative phases of the design process. The problems of CAD programs with respect to restructuring are illustrated in Figure 19. Suppose the left most figure was originally drawn on the computer as two overlapping triangles. A vertical translation of these triangles with respect to each other results in Figure 19a. This new configuration preserves the original components. This transformation, which is a form of combining, however, will not have been the motivation to sketch. According to the present investigations, this transformation is also easy to perform in imagery and so, there is no need for its externalization. Figure 19 The configuration on the left can be conceived as two overlapping tri- angles, in that case a results after vertical translation. But since sketching is used to restructure, a conception of the figure as four small triangles can be the result of sketching two overlapping triangles. Translation of these small triangles leads to b Sketching and creative discovery DST: design studies (page 25 ) 543 08-10-98 10:42:44 Rev 14.02x zdst$$140h Sketching is performed for the purpose of restructuring. The sketch will be inspected for emergent structures, which will be used for further processing. For instance, the sketch could also be perceived as consisting of four small triangles. In that case, Figure 19b illustrates a transformation which could have been the purpose of the sketcher, viz. the vertical translation of four small triangles. With a traditional computer program, the sketcher will meet a difficulty in performing this transformation. The computer stored the figure on the left as two overlapping triangles, according to the way they were originally drawn. The program is not able to recognize the newly emerged form69. In order to perform the vertical translation, the sketcher has to redraw the whole configuration. This extra sketch hampers the creative process, because it brings stagnation at a moment where progress is wanted. This suggests that a ‘What about looking at it this way?’ provision on computers, as suggested by Tatham70, would be a fruitful extension for contemporary computer tools. In current 3D CAD-programs, neither of the earlier-mentioned components of the creative process, combining and restructuring, appears to be supported very well. Combining is time-consuming where it has to pass effortlessly and restructuring is hardly supported at all. Current 3D CAD-programs, therefore, do not seem appropriate for supporting the creative process in the conceptual phase of design, where idea-sketches are usually made. Electronic sketch tablets, which, like paper and pencil, support unspecified input and leave the combining and restructuring to the sketchers appear to be, for the time being, more appropriate electronic ideacreation tools. Currently these tablets lack support facilities for restructuring. The efficiency of these tablets for the purpose of idea-sketching could be considerably improved, however, if functions like the ‘what about looking at it this way’-facilities could be provided. 69 Mitchell, W J ‘A computational view of design creativity’, in Modelling creativity and knowledge-based creative design, J S Gero and M L Maher (eds) Erlbaum, Hillsdale (1993) 70 Tatham, E W I’ll know what I want when I see it.: Towards a creative assistant Proceedings of the Human-Computer Interaction Conference Cambridge University Press (1995) pp 267–278 The research was performed, in order to obtain recommendations from psychological research, on how to improve the efficiency of idea-creation tools. The present conclusions show, that such recommendations could give a direction to the further development of such tools, such as pursued in the IDEATE project. The wider impact for psychology of these studies, however, will be found in the field of mental imagery research. The studies showed that creative processes that are likely to take place in mental imagery will be combining processes. Creative processes less likely to take place in mental imagery are instances of restructuring. What is the significance of these studies in the context of inventive cognitive processes? It has been acknowledged that such processes rely exten- 544 DST: design studies (page 26 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:44 Rev 14.02x zdst$$140h sively on visual imagery. In the light of the previous conclusions on restructuring versus combining mental imagery, questions can be raised about the claims by some famous creative individuals that their discoveries were made in mental imagery. Kekulé claimed to have made his discovery of the solution for the benzene problem while seated half asleep before his fire place. For Kekulé, the incentive to restructure his image was the detection of a molecule with an, at that time, impossible ratio of components. Kekulé was dozing at the fireplace, Poincaré jumped on a bus, and Archimedes was bathing. These unusual locations illustrate what these stories have in common. All these innovators were struck by the solution for their problem at a particular moment where none of them had paper and pencil at hand. One possibility is that the claims simply are wrong71,72. Yet, they are taken very seriously in the creativity literature and therefore deserve our consideration. Secondly, there is the possibility that only combining and no restructuring took place. This would also be unlikely, certainly in Kekulé’s case. Kekulé discovered that he had to drop the organic-molecules-canonly-exist-in-strings rule. In his days, this rule formed an essential component in the description of organic molecules. This component of the description had to be dropped, and therefore, the whole structure had to be reorganized. Such a process is likely to involve restructuring. Also Archimedes, who had to decide on the volume of the King’s crown to find out whether it was made of pure gold or if the manufacturer had played a scurvy trick and had mislead the King, knew that he had to drop as inappropriate all hitherto known rules for establishing volume, given the irregular shape of the crown. Only after dropping these rules as irrelevant, did Archimedes have the option of finding an alternative. These operations involve the perception of novel attributes of the situation, an operation akin to restructuring. 71 Weisberg, R W ‘Problem solving and creativity’, in The nature of creativity, R J Sternberg (ed) Cambridge University Press (1988) pp 148–176 72 Weisberg, RW and Alba, JW ‘An examination of the alledged role of ‘fixation’ in the solution of several ‘insight’ problems’ Journal of Experimental Psychology: General Vol 110 (1981) pp 169–192 In most cases of cognitive innovation, the inventions involved getting free from an original conception, which is probably identical to restructuring. So far, the situation is parallel to the experiments; External conditions coerce the subject into restructuring. What then facilitated restructuring in these inventors in situations where no possibilities for externalization were available? Maybe, a wider interpretation of what occurred in the component detection experiments will be helpful. In these experiments, when coerced into restructuring, subjects spontaneously turned to sketching, when allowed to. Their image would then be restructured in analogy to their sketch. In the experiments the detection was frequently reported to be very surprising. The surprising character of the detection matches per- Sketching and creative discovery DST: design studies (page 27 ) 545 08-10-98 10:42:44 Rev 14.02x zdst$$140h fectly the usual definition of insight, e.g. ‘... previously unseen and unexpected connections reveal themselves to the mind’ (Langley and Jones73, p. 177). The role of analogy in creative thinking has been emphasized by many theorists65,74,75. Possibly, extraordinarily creative individuals were able to construct analogies within imagery, for which others, in more mundane cases, require a sketch. The occurrence of visual analogies is a familiar observation from the self-reports of these individuals. Kekulé discovered, after months of confusion, that he had to drop the molecules-can-onlyexist-in-strings rule, by seeing a snake biting his own tale in the flames of his fire-place, and spontaneously envisioned this snake to be a organic molecule string. Archimedes saw the water-level of his bath raising while he stepped in, and although he must have taken many baths before, he suddenly realized the one to one relation of rising water level and the volume placed in the water. Both individuals may have found their solution eventually through this vehicle of visual analogy, after a long incubation period. 73 Langley, P and Jones, R ‘Computational model of scientific insight’, in The nature of creativity, R J Sternberg (ed) Cambridge University Press (1988) 74 Perkins, D The mind’s best work Harvard University Press, Cambridge MA (1981) 75 Polya, G How to solve it Princeton University Press, Princeton, NJ (1945) Not all inventors, however, reported to have found the solution through analogies. Poincaré is the notable exception among these self-reports of extremely creative individuals. This suggests that even without an overt visual analogy, a restructuring of knowledge can take place. Anyhow, it took time before the restructuring took place spontaneously. Kekulé and Archimedes needed time for the ‘sudden flash of insight’ to occur as well; they happened to recognize an analogy in an event that took place in their environment. Hence the tentative but straightforward suggestion is that sketching provides the analogies necessary to shorten the incubation period. To speak with Archimedes, the motto will be: Have a bath, but make a sketch before the water runs cold! 546 DST: design studies (page 28 ) Design Studies Vol 19 No 4 October 1998 08-10-98 10:42:44 Rev 14.02x zdst$$140h
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