Constraints and End User Development
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An Exploration of Constraints and End User Development in Environments for Creative Tasks
Tim Coughlan & Peter Johnson HCI Group, Department of Computer Science, University of Bath
Acknowledgments: The authors would like to thank the Engineering and Physical Sciences Research Council U.K. for funding this research, and the participants who gave their time to evaluate the system.
Contact: T. Coughlan,
[email protected]
Cite as: Coughlan, T., & Johnson, P. (2008). An exploration of constraints and end user development in environments for creative tasks. Intl. Journal of Human–Computer Interaction, 24(5), 444-459.
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Abstract
Creative tasks are performed within constraining structures. However, the exploration and development of these structures is central to the creative process. This paper summarises research on the role of constraint in creative tasks, defines the role of constraint development in a model of the creative process and classifies types of constraint in order to inform the design of environments for creative tasks. We explore links between constraint development and end user development in software environments through analysis of the design and use of Music Builder, a prototype for the user development of musical instruments in a collaborative composition environment. Conclusions include the value of scaffolding as a metaphor in design, the utility of collaborative constraint development to negotiation and coordination and the value of sharing structures in collaborative development.
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An Exploration of Constraints and End User Development in Environments for Creative Tasks
Creativity has been studied across a wide range of disciplines, leading to a detailed understanding of the processes involved from multiple perspectives. Our aim is to take what is appropriate from this body of knowledge and translate it into useful information for the design of interactive systems. Therefore we need to understand how people interact with the environment and each other in creative tasks. Creative work can be understood inclusively as a tension between divergent and convergent thinking (Baer, 2003), an iterative process of ideation, representation and evaluation (Coughlan & Johnson, 2006), and as occurring where challenging problems are matched to skills and motivation (Csikszentmihalyi, 1996). Additionally the interaction of individuals in a society develops structures through which creativity occurs and shapes the evaluation of creative outputs (Csikszentmihalyi, 1996). Throughout these perspectives, a ubiquitous property of creative work is that constraining motivations, tools and conceptual structures are necessary to direct and support creative activities, but that the ongoing questioning and development of these structures is central to the process. Across domains, creative work occurs within various structures, from a physical instrument, to a software environment, to a language developed to formalise specific concepts. It is however essential to supporting and promoting creative thought that practitioners have the ability to explore and modify aspects of these structures. The novelty required in a creative output commonly arises through the use of novel variations or combinations of concepts and tools, compelling creators to explore paths less followed. We argue that computer-based environments for creative tasks both constrain the creative process in new ways and provide new possibilities for creators to work with constraints, particularly
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through the notion of end user development. To move from theoretical understanding to practical design knowledge we analyse the design and use of a system for the user development of musical instruments. The atomic elements of creative work are ideas – a thought or suggestion of a possible course of action. The nature of an idea is domain-specific, as are the forms through which it is represented (Coughlan & Johnson, 2006). Ideas do not occur in a vacuum, but exist with reference to specific situations, knowledge and stimuli, and in response to problems we are motivated to explore. Finding these problems of interest is key, whilst problem solving is ill structured, because the path to a suitable solution is not clear as the task is performed. Spatial metaphors have been used to represent the creative process from this perspective. Creators approach a new task with a wide, unexplored solution space, forming a vast array of possible actions (Boden, 1991). Decisions are made to place boundaries within this space or choose areas to explore. A minimalist overview of a creative process would begin with initial exploration of some of a vast range of possible actions – perhaps by making rough sketches, brainstorming, or exploring musical possibilities through playing an instrument. The space of possibilities diminishes in scope as choices are made to keep or discard ideas and concepts that have emerged – for example if a particular musical phrase or subject matter is identified as valuable, subsequent ideation and evaluation will take it in to account. In reality there can be a great deal of deviation and reversal as creative practitioners develop and reflect on the intended outcome at various levels.
Constraints in Creative Work
Research has highlighted the centrality of constraints to creative processes across creative domains: Scientific theories are created as possible solutions within a set of observed
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constraints. Designers are generally presented with initial constraints required of any solution, such as health and safety laws or limited budgets. Artistic work is perhaps less constrained by external prescription, but in its place practitioners enforce constraints to focus their activity, for example by concentrating on a single subject matter or restricting the materials with which they work. Stokes argues that useful constraints preclude conformist, tried and tested responses and promote novelty. Successful creators generate novel, valuable products by finding or developing demanding task and subject constraints that partially define an overall goal of interest (Stokes, 2006). In design, constraints are commonly identified as a basis for bounding the design space in which solutions must fit. A range of constraints from cost or available materials to the functions required of the design can be identified and used to frame the process. Chandrasekaran notes that “all design can be thought of as constraint satisfaction” but in design tasks of any complexity the space satisfying constraints that can be formally defined remains large, with many ‘correct’ solutions (Chandrasekaran, 1990). Pérez y Pérez and Sharples classify constraints in creative writing either as external factors - tools and resources existing in the world, or mental constraints that reflect requirements for content or rhetorical issues of how best to compose for the audience. Writing involves periods of engagement and reflection. Engagement entails realising ideas that are expected to comply with constraints. Constraints “drive the production of material during engagement”, but writers also enter periods of reflection when they run low on ideas or feel compelled to depart from current constraints due to divergent thinking (Pérez y Pérez & Sharples, 2001). In modelling the process of musical composition, Pearce and Wiggins identify three types of constraints on the composer: Internal - the requirement to fit with existing ideas in the composition, external - the limitations on what it is possible to create,
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given current skills, tools and knowledge, and stylistic - constraints relating to the intended outcomes and genre (Pearce & Wiggins, 2002). Although some form of collaboration is inherent to most creative work, collaborative constraint development is little understood. Collaborative creativity is also poorly served by existing computer environments; for example there is a stark contrast in the musical domain between the highly collaborative nature of most musical endeavours and the single user design of the vast majority of music software (Coughlan & Johnson, 2006). Therefore this research explores the role of constraint development in mediating creative collaboration.
A Model of Constraint Development in the Creative Process
Combining existing creativity research with analysis of our previous observational studies (Coughlan & Johnson, 2006), we have developed and refined a descriptive model of the creative process. Creative work is defined as a cyclical, iterative process of ideation – the generation and representation of novel thoughts - and evaluation – reflection on the value of generated ideas. These cycles are interspersed by periods of constraint development, a subprocess that considers the fit of existing constraints, how new constraints could affect the outcome and then implements changes to the constraint structure. The model has been developed to aid general understanding of creativity support needs and to define the role of constraint development.
Forms of Constraint Our model defines three forms of constraint from the perspective of designing technological support. Tangibility is the essence of the external constraints of Pearce & Wiggins and the task constraints of Stokes. We therefore define tangible constraints as
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properties in the virtual or physical environment that have defined qualities and limitations, such as a painter’s palette or the range of a piano. Subject and goal constraints in Stokes’s definition are, like Pearce & Wiggins’s stylistic constraints and Pérez y Pérez & Sharples mental constraints, conceptual notions that have no defined form. We therefore define conceptual constraints as those constraints that exist in the minds of practitioners, such as aiming to create a painting in an impressionist style. Finally, Pearce & Wiggins’s notion of internal constraints highlights an essential factor in the process of composing creative solutions and should be central to the development of support environments. Examples of internal constraints include a drumbeat that a collaborating musician should play to, or a figure in a painting that additional features must fit around. In addition to considering forms of constraint, the model considers that at some level constraints are either malleable or static. In any creative process there will be supporting tangible and conceptual structures that remain static and provide the basis from which malleable constraints are built – for example a writer might only use the English language, or a musician only a specific software environment. By considering the static constraints in any given situation, we can differentiate and analyse the areas in which practitioners consciously explore constraints, and the underlying structures used to frame this exploration.
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Figure 1: Model of Constraint Development in the Creative Process
Explanation of Process A cycle begins either with an initial development of constraints or exploratory ideation in the existing constraint structure. Each phase of ideation is informed by the current conceptual and internal constraints, and bound by the enforced tangible constraints. Tangible constraints and ideas are evaluated with reference to conceptual goal constraints, leading to decisions on whether to retain an idea – in which case it becomes an internal constraint, and also whether to maintain or transform current constraints. While constraints are maintained, cycles of ideation and evaluation form the basis of the creative process. If a decision to develop constraints is taken, conceptual constraints may be reconsidered, or tangible constraints modified where possible. A cycle of ideation and evaluation then tests the validity of the new constraints. For example, musicians may begin composing by choosing instruments, a scale, key and / or a theme. Next they perform ideation within this space, for example through exploratory play. They evaluate what they play with respect to aesthetic sensibilities and
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conceptual goals, and use this to consider whether to retain played ideas in the composition, and whether to modify or add to the constraints they have built. They may later find and retain a specific musical phrase and build the rest of the composition around it, using the inherent internal constraints to reduce the solution space.
Constraint and End User Development in Creative Interaction Design
Constraints form an important conceptual lens through which to view the design of environments for creative tasks. Environments that are open to manipulation through end user development mirror the creative mind by allowing users to question and explore boundaries (Smith, 1993). The virtual can be far more malleable than the physical environment, as our prototype study highlights. However limitations can form useful points of reference, setting fixed structures within which creative work occurs and is understood. The computer “enhances freedom for exploration, but also contains within it the potential tyranny of continual choice” (Haworth, Coldwell, Gollifer, Kemp, Faure-Walker & Pengelly, 2005). Conversely, well-designed software environments can aid the development and use of constraints by promoting reflection and ensuring that constraints are satisfied. Candy notes that a tool for scientific visualisation “presents the existing constraints, the human revises them and the resources of both are employed in the process of considering and negotiating plausible revisions” (Candy, 1997). The interface defines a tangible constraint structure that is to some degree comparable to the physical constraints of a non-computerised environment, as the properties of the interface define the scope of possible actions. Our theoretical understanding suggests that it should aid users to be aware of the tangible constraints imposed upon them and be
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empowered to apply and manipulate them where feasible. The structures provided to manipulate the environment then define the static constraints on the user. It is also common for environments for creative tasks to support the capture and representation of ideas. Across domains, composition requires an understanding of the internal constraints inherent in the combination of ideas expected to form the outcome. As the computer understands elements of user’s ideas in more detail, it becomes more of a partner in the process by providing useful feedback and a powerful interface for manipulation, but this requires a formal structure that enforces specific processes and restricts possible forms of representation. Environments for musical composition in particular provide only a fixed set of unambiguous representations through which users can define, evaluate and combine ideas, allowing the computer to interpret them and produce music. In contrast, composition with paper and standard instruments supports ambiguous representation and an ad-hoc process of formalisation as musicians interpret, play and develop compositions based on the representations (Coughlan & Johnson, 2006). In summation we argue that relationships between designers and users need reassessment in light of two issues. Firstly computers structure creative processes to a far greater extent than other tools and demand greater formality from users. Secondly, computers can conceivably empower users to explore constraints, and to develop and exchange not only ideas, but also structures for creativity. There is great value in the artist / technologist collaboration (Edmonds, Weakley, Candy, Fell, Knott & Pauletto, 2005), as creative practitioners can be stifled in explorations of technology by a lack of technical skill. Beyond these fruitful situations, can we free end users to develop and manipulate interfaces for creativity without extensive technical expertise? The prototype study and analysis presented here is used to explore this question and consider the value of this concept to users.
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Music Builder: User Development of Instruments for Collaborative Composition
A prototype system was designed to ground our theoretical work and identify practical issues with constraint in user development environments. We focused on three design aims: 1.
Provide a support environment for collaborative musical composition.
2.
Be inclusive through flexibility. Support individual needs in a collaborative context,
and the development of shared representations of ideas and constraints. 3.
Encourage the development of constraining structures as a central part of the creative
process, without forcing users to become developers Music Builder supports the user development of musical instruments in a networked environment for collaborative composition. Tablet computers form a flexible physical platform with which to create music through screen-based instruments, and hold some appealing qualities as a musical interface: Interaction using a pen is less restrictive than with a mouse or track pad, and the direct mapping between the elements displayed on screen and the pen supports hand-eye coordination.
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Figure 2: Playing a Music Builder Client
Music Builder consists of three spaces corresponding to elements of the model presented. The three spaces are designed to support fluid movement between creating instruments, playing music and developing compositions. In the build space shown in figure 3, users can develop their own instruments in order to manipulate tangible constraints. These instruments can then be used to play and record musical ideas in the play space, shown in figure 4. Recordings made in the play space can then be replayed, combined and manipulated collaboratively in the composition space shown in figure 5. This supports the evaluation of ideas, reflection upon internal constraints and composition development.
Constraints and End User Development
Figure 3: Build Space
Figure 4: Play Space
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Figure 5: Composition Space
The underlying structure of the building interface focuses on the essential properties of musical instruments, defined as a means of gesture-based input mapped to a sonic output (Hunt, Wanderley & Kirk, 2000). Instruments are developed by adding interaction shapes to a free-form space, and defining how interactions with each shape (such as pressing, holding or dragging) map to output values for sonic properties such as pitch, volume or voice. Users link shapes to sound sources, which receive output values from the shapes, add these values to their initial settings and produce sound. Figure 6 depicts shapes and sound sources linked to form an instrument. To support informal representation, users can also draw anywhere on the screen, using the space as a sketchpad.
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Figure 6: Sound Sources and Interaction Shapes combined to form instruments
Scaffolding In designing a system through which users can create instruments, a trade off is apparent: Complex environments usually involves a considerable learning process and rarely support immediate engagement with ideas, while simplification enforces additional static constraints on possible actions, for example by limiting the range of functions and options available. We wished to reduce constraints without creating difficulties for new users. To achieve this the metaphor of scaffolding was considered in the design. In educational research scaffolding is an accepted practice where teachers create a supporting environment for a student to learn through action, with structure provided but removed as students develop the skills required to work independently (Wood & Wood, 1996). We consider this notion important to support for constraint development, aiming to provide an initial level of constraint that is supportive of immediate action, but open to manipulation and removal by users at will. The scaffolding in the prototype takes the form of seven template instruments, provided to engage users immediately and to make visible some of the possibilities of instrument building. These represent a cross-section of possible interaction styles and sounds,
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including a drum kit, a piano and a Theremin style instrument where the pitch and volume vary with proximity of the pen to a shape.
Collaborative Composition Using Music Builder The system allows users to record instrument play individually or simultaneously from both machines. This allows users to collaborate in a variety of ways, for example by developing ideas individually then sharing them, or by jamming together and recording the outcome. To support composition using these recordings, the prototype provides a shared, networked space, based on the Sonic Sketchpad software developed and evaluated previously (Coughlan & Johnson, 2006). This version employs the same notion of a library of recordings and a paper-like space for composition where users can freely manipulate, arrange and link recordings and add annotations, avoiding excess constraints on the representation of ideas.
Observational Studies of Music Builder Use
After an initial pilot study and work to address the basic usability issues identified through this, 12 participants took part in the main study in 6 collaborating pairs. Musical experience was varied, in keeping with our notion of support for a wide range of users.
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Participants included a pianist with 17 years of musical experience, a guitarist and a drummer both having over 10 years of experience and a computer musician with 4 years of experience using the software environments Cubase and Reason. At the other extreme, several of the participants had only limited musical education, mainly from school lessons. Collaborators were in some cases unknown to each other, but were generally friends who took part together. The studies took place in a usability lab, where screen-capture devices and cameras provided a video record. The software logged actions to provide an accurate picture of user’s interaction with Music Builder. Participants filled in questionnaires after each session and a final exit questionnaire. As one of our aims was to explore requirements for the design of systems to support collaborative constraint development, we used the evaluations of the system to examine the utility of shared visual and physical space to collaboration. Participants used the system under the following three conditions in a within participants design:
1: Users co-located in the same physical space 2: A partition separating users, with a display repeating their collaborator’s screen 3: Users either side of a partition without shared screens
Participants could talk freely and hear output from the same set of speakers across the conditions. A written tutorial was provided walking users through the features of the environment. Participants were then asked to use the environment to produce a short composition they were happy with under each condition, with the system wiped and restarted after each composition was finished. No time limits were applied.
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Analysis
In analysing use of the prototype, we wanted to learn if, why and how musicians would develop instruments in order to understand how interaction with these constraints occurred. We looked for evidence supporting the validity of a user development approach and issues relating to this, and the utility of the scaffolding and screen sharing. A further aim was to relate our model to observations of interaction between creators and a software environment. Users spent between one and a half and three hours creating the three compositions. In many cases users were still exploring new and interesting ways to interact with sound throughout this time, and opinions of the instrument development concept were generally very positive, particularly amongst participants with a previous interest in computer music.
Development of Constraints Of the 12 participants, 8 made use of instrument building in at least one of the conditions, while the remaining 4 used the template instruments throughout. As each participant used the system 3 times, there were a total of 36 sessions. Each session was categorised in to one of 4 use types based on system logs: •
Multiple Instrument Edits – Users cycled between instrument development and play / composition
•
Multiple Templates – Users changed templates between periods of play and composition but did not develop instruments
•
Single Instrument Builder – Users developed an instrument initially which they used to play / compose without further editing
•
Single Template – A single template was used throughout the session
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Figure 7: Frequency of Use Type By Session
The statistics presented in figure 7 provide evidence of user interest in the development of instruments, and also that development commonly occurs cyclically and in tandem with composition. Instrument development occurred in the majority of sessions, and in almost all of these cases instruments and musical ideas were developed in cycles. Participants used the ability to develop tangible constraints that defined conceptual structures. A common example being the rearrangement and removal of notes on an instrument, either to constrain play to a specific scale, or alternatively to constrain the instrument to allow only the notes in a musical phrase to be played. The ability to manipulate instruments also supported user innovation to overcome difficulties in achieving complex goals. An experienced drummer linked shapes to multiple drum Sound Sources, enabling him to play two or more drums with each tap. Through this he developed complex drum patterns, overcoming the limiting effect of single-handed input.
Scaffolding In 30 of the sessions the participant’s first action was to load a template instrument, while in the remaining 6 sessions it was to build an instrument on a blank canvas. We learnt through our observations that scaffolding fulfilled multiple user needs, providing a starting point for instrument development, a basis for exploring the possibilities that exist in the environment and an immediate ‘pick up and play’ structure. Users generally focused on manipulating sonic constraints such as the range of notes or voices, rather than exploring the various forms of interaction available, and the templates provided an existing structure for interaction from which these sonic properties could be quickly modified and tested.
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Collaborative Development of Instruments Instrument development can be seen as a design task to develop a structure from which a creative output can emerge. The design of each other’s instruments was a common theme of the dialogue between collaborators. Instrument design not only affects the group’s musical capabilities, it provides a platform through which roles are coordinated and intentions are explained. Qualitative analysis of approaches to development suggests that sharing tangible constraints was a successful strategy for coordinating collaborative play. Extended discussions of tonal properties and instrument structure were common. In one session a user asked if he could pass his instrument over to his collaborator. Unfortunately this was not supported here, but could provide an interesting extension. In the short-term, the collaborative development of instruments with shared constraints provides a basis through which collaborators negotiate conceptual and tangible constraints for the intended composition. Further to this, instruments could evolve as tangible constraint structures passed over networks as formal social constructions for musical creativity. The excerpt below gives an example of collaborative development behaviour. By describing the instrument as it is built and identifying a shared concept to realise, the collaborators produce complementary instruments through which coordinated ideation is effectively constrained: P1 and P2 discuss how to proceed P2: “Ah, shall I make a jazz scale keyboard?” P1: “Yeah go on then” P2: “Do you know jazz scale?” P1: “Um, not really, tell me the notes” P2: “OK hang on I’ll load up the piano and…” P1 and P2 both load the piano template P2: “That’s A, D, C… so we need to get rid of that one” P2 removes several keys from the piano, P1 looks at the shared screen and removes the same keys P2: (looks at P1s actions on the shared screen) “Yeah, look at the screen, you can see what I’m doing” P1 plays the new keyboard, P2 puts the notes in order across the screen, P1 copies this action. P2: “I think we need two octaves of these (keys)” P1 and P2 add a second set of keys an octave higher.
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Three reasons for the success of this behaviour are suggested here: Firstly the externalisation of constraints focuses effort on working within those constraints, rather than developing ideas solely through conceptual notions which collaborators may define differently. Secondly enforced, shared constraints make a collaborator’s actions more predictable and provide a form of awareness information, narrowing the possible actions a collaborator could take and increasing the likelihood of coherent collaborative play. Finally, by restricting the instrument to notes that fit within a structure such as a scale, there is no longer the need to use cognitive resources to evaluate whether the desired constraint is being fulfilled, as it is impossible for it not to be so. These resources can instead be used to evaluate the validity of ideas in terms of conceptual constraints, to attend to a collaborator or to generate further ideas. The excerpt also shows the value of shared visibility as a basis for explanation of concepts. Collaborative developers used the shared screen when provided as a means to understand each other’s instruments, and questionnaire responses provided further evidence for the value of being able to view and compare instrument development. Further support for this process could focus on allowing collaborators to better ‘read’ their collaborator’s instrument by making more details of instrument properties visible.
Conclusions
In this research we have highlighted the suitability of end user development to environments for creative tasks. Supporting the development of tangible constraints has
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several important benefits: Analysis of the observations suggested that a strategy of collaborative instrument development promotes awareness and synergy and provides a structure within which successful collaborative play was significantly easier. When possible, the movement from conceptual constraints towards tangible structures promotes the formalisation and evaluation of concepts as individuals and between collaborators. Creative tasks involve the realisation of ideas fulfilling a set of constraints that often begin as ambiguous or intangible concepts. The user development of the environment can support the representation of these and allow new forms of reflection. Additionally, these systems can reduce the constraining influence of the designer on the user by supporting the modification of the environment. There were multiple occasions where users created instruments with properties that we as designers would never have considered ourselves, providing a valuable source of innovation and a reduction of barriers to realising ideas. In conclusion we present the following requirements in designing support for creative end user development:
Provide scaffolding to support the immediate use and exploration of the environment Creativity support environments need structure, but structure that can be pulled apart by users at will. However the consistent availability of initial structures to adopt and explore provided inspiration and was preferred to building from a blank screen. The ‘tyranny of choice’ arises through a lack of available structure, and making tangible constraints in the environment flexible may compound these problems. This was not apparent with Music Builder because the templates offered the required initial structure.
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Support the sharing of developed structures and the visibility of actions in constraint development. The shared screen afforded users the ability to see collaborator’s actions, aiding the communication of tangible constraints, however alternative designs for these interactions may be more appropriate. The possibilities for sharing a single space are interesting, but could be detrimental to the independence of users. Passing instruments or other constraining structures between collaborators and across networks could provide a better model for user development in creative tasks. Developed instruments form important representations of user’s intentions, so the ability to read properties of each other’s instrument and gesture towards elements in the space is key to communication.
Support fluid movement between ideation, tangible constraint development and evaluation. Constraint development does not occur only as an initial stage of the creative process. It is in general a reaction to the evaluation of represented ideas. As such environments should fluidly integrate the representation of ideas and of constraints and allow users to explore the interdependence of the two. Music Builder provides an example of the rich design space for software integrating the representation of ideas with the development of constraints to support both engagement and reflection in creative tasks.
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References
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Haworth, J., Coldwell, P., Gollifer, S., Kemp, T., Faure-Walker, J. & Pengelly, J., (2005) Freedom and Constraint in the Creative Process in Digital Fine Art: An AHRB Invited Workshop, Proceedings of Creativity & Cognition 2005, ACM
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Constraints and End User Development Figure 1: Model
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Constraints and End User Development Figure 2: Playing a Music Builder Client
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Constraints and End User Development Figure 3: Build Space
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Constraints and End User Development Figure 4: Play Space
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Constraints and End User Development Figure 5: Composition Space
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Constraints and End User Development Figure 6: Sound Sources and Interaction Shapes
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Constraints and End User Development Figure 7: Frequency of Use Type by Session
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