The cognitive dimensions framework is a broad-brush evaluation technique for interactive devices and for non-interactive notations. It sets out a small vocabulary of terms designed to capture the cognitively-relevant aspects of structure, and shows how they can be traded off against each other. The purpose of this paper is to propose the framework as an evaluation technique for visual programming environments. We apply it to two commercially-available dataflow languages (with further examples from other systems) and conclude that it is effective and insightful; other HCI-based evaluation techniques focus on different aspects and would make good complements. Insofar as the examples we used are representative, current VPLs are successful in achieving a good `closeness of match', but designers need to consider the `viscosity' (resistance to local change) and the `secondary notation' (possibility of conveying extra meaning by choice of layout, colour, etc.).

When an opportunistic searcher encounters an over-de- or ‘‘evolving,’ ’ ‘‘contracting’ ’ and ‘‘expanding’’—is termined information system, less than ideal search strategies often ensue. The mismatch can be addressed by reducing the determinacy of the system, thereby mak-ing it more amenable to informal problem-solving prac-available, then searching is potentially richer because the chances improve that the searcher will be prompted to reformulate and abandon plans, backtrack to points of tices. This claim is investigated by designing an informa-task deferral or significant decision, and compare things tion-seeking environment, where search techniques are side-by-side. When aspects of the search process are exrepresented with a data-flow notation and where the searcher has control of layout; thus, to seek information, is to manage space. Search plans can be represented on the display, and perceptual cues about search prog-ternalized, both prospective memory, plans for the future, and retrospective memory, tasks completed, are sup-ported. In programming environments, support for these ress are captured while searching. With elements of basic cognitive tasks is considered essential because they search activity visible, opportunistic problem-solving should be well supported. The interface is designed to be extensible so a wide range of search techniques can be represented, and emphasizes search material, such as queries, results, and notes, rather than system con-trols. allow people to work the way they want to—opportunis-tically (Visser, 1994). There is no a priori reason to think they are any less important in environments for informa-tion seeking; indeed, planning, backtracking, and comparison are at the heart of search tactics and strategies (Bates, 1979a, 1979b).

A weakness of many interactive visual programming languages (VPLs) is their static representations. Lack of an adequate static representation places a heavy cognitive burden on a VPL s programmers, because they must remember potentially long dynamic sequences of screen displays in order to understand a previously written program. However, although this problem is widely acknowledged, research on how to design better static representations for interactive VPLs is still in its infancy. Building upon the cognitive dimensions developed for programming languages by cognitive psychologists Green and others, we have developed a set of concrete benchmarks for VPL designers to use when designing new static representations. These benchmarks provide design-time information that can be used to improve a VPL s static representation.

The environments programmers traditionally use for problem-solving---with separate modes and tools for writing, compiling, testing, visualizing, and debugging--- derive their basic structure from historical accident, and take little advantage of Human Computer Interaction (HCI) research into the cognitive issues of programming. We believe that neglect of these issues impedes programmers' ability to produce reliable, maintainable software. Visual programming languages (VPLs) have begun to address this problem by creating more flexible, less modal programming environments, and we have taken a step further in this direction. In this paper, we describe a VPL in which programmers can modelessly steer as they specify, visualize, explore, and alter the behavior of a program while traveling through the program's logical time. This approach supports two often-neglected cognitive principles that HCI research shows can help programmers in their problem-solving. 1. Introduction Historically, pro...

We present a new visual programming language and environment that serves as a form of feedback and representation in a Programming by Demonstration system. The language differs from existing visual languages because it explicitly represents data objects and implicitly represents operations by changes in data objects. The system was designed to provide non-programmers with programming support for common, repetitive tasks and incorporates some principles of cognition to assist these users in learning to use it. With this in mind, we analyzed the language and its editor along cognitive dimensions. The assessment provided insight into both strengths and weaknesses of the system, prompting a number of design changes. This demonstrates how useful such an analysis can be.

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Software development remains mentally challenging despite the continual advancement of training, techniques, and tools. Because completely automating software development is currently impossible, it makes sense to seriously consider how tools can improve the mental activities of developers apart from automating them away. Such mental assistance can be called “cognitive support”. Understanding and developing cognitive support in software engineering tools is an important research issue but, unfortunately, at the moment our theoretical foundations for it are inadequately developed. Furthermore, much of the relevant research has occurred outside of the software engineering community, and is therefore not easily available to the researchers who typically develop software engineering tools. Tool evaluation, comparison, and development are consequently impaired. The present work introduces a theoretical framework intended to seed further systematic study of cognitive support in the field of software engineering tools. This theoretical framework, called RODS, imports ideas and methods from a field of cognitive science called “distributed cognition”. The crucial concept in RODS is that cognitive support can be understood and explained in terms of the computational advantages that are conferred when cognition is redistributed between software developer and their tools and environment. The name RODS, in fact, comes from the

The use of graphical user interfaces in a computerised work environment is often considered to substantially improve the work situation. The outcome can, however, often be the opposite. Inappropriate use of windowing techniques, scrolling and colours can result in tedious and confusing interaction with the computer. Today's standards and style guides define basic design principles but are insufficient for design of interfaces to end-user applications. Here detailed domain knowledge is indeed essential. A domain-specific style guide (DSSG) is an extension of today's standard with domain-specific primitives, interface elements, and forms, together with domainspecific guidelines. Careful dedicated analysis of information utilisation in a domain is the development basis for a DSSG. The development is performed with an objectoriented approach to facilitate the reuse of interface components and to support consistency and structure. Using a DSSG the development of applications can be performe...

In this paper the interaction between users and the interactive theorem prover HOL is investigated from a human-computer interaction perspective. First, we outline three possible views of interaction, and give a brief survey of some current interfaces and how they may be described in terms of these views. Second, we describe and present the results of an empirical study of intermediate and expert HOL users. The results are analysed for evidence in support of the proposed view of proof activity in HOL. We believe that this approach provides a principled basis for the assessment and design of interfaces to theorem provers.

In this paper Green's (1989) notion of "cognitive dimensions" is used to consider the properties of notations and media for sketching. First, a cultural-cognitive approach to HCI research is briefly outlined which draws on some ideas from "distributed cognition" and Russian psychology. Rather than focussing on the cognitive aspects of an activity or the social aspects (as do cognitive psychology and ethnography, respectively) this approach attempts to describe the artifacts used in an activity in a cognitively and socially relevant way. It is argued that such an approach requires a framework within which to analyse external representations, and that Green's "cognitive dimensions" provide such a framework. The cognitive dimensions framework is described and then used to interpret a study of collaborative idea sketching which used interviewing, observational methods and a questionnaire survey of 128 academics. This analysis resulted in a cohesive and comprehensive characterisati...