Cognitive load theory has been designed to provide guidelines intended to assist in the presentation of information in a manner that encourages learner activities that optimize intellectual performance. The theory assumes a limited capacity working memory that includes partially independent subcomponents to deal with auditory/verbal material and visual/2- or 3-dimensional information as well as an effectively unlimited long-term memory, holding schemas that vary in their degree of automation. These structures and functions of human cognitive architecture have been used to design a variety of novel instructional procedures based on the assumption that working memory load should be reduced and schema construction encouraged. This paper reviews the theory and the instructional designs generated by it. KEY WORDS: cognition; instructional design; learning; problem solving.

Constructivism is a theory of learning which claims that students construct knowledge rather than merely recieve and store knowledge transmitted by the teacher. Constructivism has been extremely influential in science and mathematics education, but much less so in computer science education (CSE). This paper surveys constructivism in the context of CSE, and shows how the theory can supply a theoretical basis for debating issues and evaluating proposals. An analysis of constructivism in computer science education leads to two claims: (1) students do not have an e#ective model of a computer, and (2) computers form an accessible ontological reality. The conclusions from these claims are that: (1) models must be explicitly taught, (2) models must be taught before abstractions, and (3) the seductive reality of the computer must not be allowed to supplant construction of models. Introduction The dominant theory of learning today is called constructivism. This theory claims that knowledge is actively constructed by the student, not passively absorbed from textbooks and lectures. Since the construction builds recursively on knowledge that the student already has, each student will construct an idiosyncratic version of knowledge. To

People working collaboratively must establish and maintain awareness of one another's intentions, actions and results. Notification systems typically support awareness of the presence, tasks and actions of collaborators, but they do not adequately support awareness of persistent and complex activities. We analysed awareness breakdowns in use of our Virtual School system---stemming from problems related to the collaborative situation, group, task and tool support---to motivate the concept of activity awareness. Activity a areness builds on prior conceptions of social and action a areness, but emphasizes the importance of activity context factors like planning and coordination. This ork suggests design strategies for notification systems to better support collaborative activity.

this paper, I review the history of HCI as steps toward a science of design. My touchstone is Simon's (1969) provocative book he Sciences of the Artificial. The book pre-dates HCI, and many of its specific characterizations and claims about design are no longer authoritative (see Ehn, 1988). Nevertheless, two of Simon's themes echo through the history of HCI, and still provide guidance for charting its continuing development

Claims have been proposed as a means of expressing HCI knowledge that is associated with a specific artefact and usage context. Claims describe design trade-offs and record HCI knowledge related to a specific design, or artefact, as psychological design rationale. Claims are created in the task-artefact cycle of interactive design and evaluation. Usability evaluation establishes a claim for a specific usage context, but this can restrict subsequent reuse of claims related knowledge. To widen the scope of reuse the knowledge contained within claims and their associated artefacts has to be classified and generalized. To address this problem a schema and method for classifying claims is introduced. The schema elaborates the description of HCI knowledge in claims and enables reuse by describing the assumptions and dependencies upon which a claim rests. Methods for generalising claims and discovering new claims from existing claims and artefacts were investigated. A factoring method for evolving child claims from parent claims and their usage scenarios is described. This employs a walkthrough technique based on Norman’s model of action with questions directed at the contributions a claim makes to usability at different stages in interaction. Factoring promotes evolution of child claims that either address different aspects of task support in the same domain as the parent claim, or development of more general child claims for user interface design. The relationships between claims are represented in maps to illustrate histories of task-artefact investigation that lead to claims evolution either via the factoring process or by empirical investigation. The schema and method for claims evolution are illustrated by case studies of claims development in tutoring systems and claims for functional requirements for specification reuse support tools. The paper concludes with a discussion of the contribution that reusable claims can make as a repository of HCI knowledge. 1 1.

Technology development in HCI can be interpreted as a co-evolution of tasks and artifacts. The tasks people actually engage in (successfully or problematically) and those they wish to engage in (or perhaps merely to imagine) define requirements for future technology, and specifically for new HCI artifacts. These artifacts, in turn, open up new possibilities for human tasks, new ways to do familiar things, entirely new kinds of things to do. In this paper we describe psychological design rationale as an approach to augmenting HCI technology development and to clarifying the sense in which HCI artifacts embody psychological theory. A psychological design rationale is an enumeration of the psychological claims embodied by an artifact for the situations in which it is used. As an example, we present our design work with the View Matcher, a Smalltalk programming environment for coordinating multiple views of an example application. In particular, we show how psychological design rationale was used to develop a view matcher for code reuse from prior design rationales for related programming tasks and environments. 1. TASKS AND ARTIFACTS In 1605, Sir Francis Bacon called for a "natural history of trades." He urged that technical tools, techniques and processes be made more public and explicit. This was one element in his broader project of developing practical science, and hinged on the assumption that if such knowledge could be more systematically considered and integrated, human progress would necessarily result. Thus, Bacon suggested that new concepts and inventions would result "by a connexion and transferring of the observations of one Arte, to the use of another, when the experiences of several misteries shall fall under the consideration of one man's minde."(1970: Book...

Abstract: In this paper, we recruit the construct of psychological design rationale as a framework for integrating theory development with design evaluation in HCI. We propose that, in some cases, part of an artifact’s psychological design rationale can be regarded as inherited from second-order artifacts (prescriptive design models, architectures and genres, tools and environments, interface styles). We show how evaluation data pertaining to an artifact can be used to test and develop the second-order artifacts from which it inherits. 1.

The empirical study described in this paper addresses software reading for construction: how application developers obtain an understanding of a software artifact for use in new system development. This study focuses on the processes that developers would engage in when learning and using object-oriented frameworks. We analyzed 15 student software development projects using both qualitative and quantitative methods to gain insight into what processes occurred during framework usage. The contribution of the study is not to test predefined hypotheses but to generate well-supported hypotheses for further investigation. The main hypotheses we produce are that example-based techniques are well suited to use by beginning learners while hierarchy-based techniques are not because of a larger learning curve. Other more specific hypotheses are proposed and discussed.

This paper describes LICAI, a model that simulates peforming tasks by exploration where the tasks are given to the user in the form of written exercises that contain no information about the correct action sequences. LICAI's comprehension processes and the action planning processes are based on Kintsch.'s .constmc. tion-in,tegrafio n theo for text comprehension. The model comprehends me mstmcuons ano generates goats which are then stored in memory. The action planning process is eontroled by goals retrieved from memory cued by displays generated by the application.

Although researchers have begun to explicitly support enduser programmers ’ debugging by providing information to help them find bugs, there is little research addressing the proper mechanism to alert the user to this information. The choice of alerting mechanism can be important, because as previous research has shown, different interruption styles have different potential advantages and disadvantages. To explore impacts of interruptions in the end-user debugging domain, this paper describes an empirical comparison of two interruption styles that have been used to alert end-user programmers to debugging information. Our results show that negotiated-style interruptions were superior to immediate-style interruptions in several issues of importance to end-user debugging, and further suggest that a reason for this superiority may be that immediate-style interruptions encourage different debugging strategies.