Abstract not found

The thorny problem of usability has been recognized in the security community for many years, but has, so far, eluded systematic solution. We characterize the problem as a gap between theoretical and effective levels of security, and consider the characteristics of the problem. The approach we are taking focuses on visibility- how can we make relevant features of the security context apparent to users, in order to allow them to make informed decisions about their actions and the potential implications of those actions?

People feel they understand complex phenomena with far greater precision, coherence, and depth than they really do; they are subject to an illusion—an illusion of explanatory depth. The illusion is far stronger for explanatory knowledge than many other kinds of knowledge, such as that for facts, procedures or narratives. The illusion for explanatory knowledge is most robust where the environment supports real-time explanations with visible mechanisms. We demonstrate the illusion of depth with explanatory knowledge in Studies 1–6. Then we show differences in overconfidence about knowledge across different knowledge domains in Studies 7–10. Finally, we explore the mechanisms behind the initial confidence and behind overconfidence in Studies 11 and 12, and discuss the implications of our findings for the roles of intuitive theories in concepts and cognition.

Resting objects can be described according to the physical forces operating on them, forces that are balanced in static scenes. We hypothesized that in a related way, the perception of static scenes and objects might involve a representation of underlying dynamics. In our first experiments, subjects were shown a picture of a plant resting upon a table or hanging from a hook, followed by a picture of the plant in the same position without the supporting table or hook. Subjects attempted to remember the position of the plant and were then shown a third display, in which the plant was in the same position or was slightly above or slightly below the original position. We found that subjects made more errors for test displays showing the plant slightly below, as compared with displays showing the plant slightly above, the original position. That is, memory for the position of the previously supported object was distorted in the direction consistent with what would happen if the plant was to lose its source of support in real life. This effect depends on the initial display of support; in Experiment 2 we found no memory asymmetry when the plant was initially displayed without support. We replicated the results of Experiments 1 and 2 with a new stimulus set and

Intelligibility is one of the key factors affecting the acceptance and effective use of information systems. In this article, we discuss the ways in which recognition of this factor challenges current system design strategies, as well as current theoretical perspectives and research methodologies. In particular, we claim that in order to understand the problem of system intelligibility, we must focus not only on the cognitive, but also on the social aspects of system use. After considering some of the sources of users ’ difficulty in understanding information systems, we propose a new global philosophy for interface design: design for the management of trouble. We discuss the design implications of four mechanisms for improving system intelligibility: (1) useful mental models of the system and its associated subsystems, (2) communicative repair in user-system interaction, (3) new training strategies, and (4) use of the larger social environment as an aid to understanding information systems.

Several earlier investigations found that teaching standard textbook physics causes only moderate change in qualitative understanding. Manyinvestigations have tried to explain why teaching textbook physics results in so little learning of qualitativephysics. In contrast, we examined cases where learning did occur and tried to understand them, hoping that this might help us to understand how to support such learning. We developed computerized simulation models of both qualitative, conceptual problem solving and quantitative problem solving and used them to assess changes in students' qualitative knowledge as they learned textbook physics. In many cases, qualitative knowledge has been acquired on the basis of information explicitly presented in the textbook. However, we also found cases where learning of qualitativephysics took place on the basis of information only implicitly addressed in the instruction. Even more important, in various cases this newly acquired qualitative knowledge led to a less frequent use of incorrect qualitative pre-knowledge. This suggests that successfull students did not only learn what has been explicitly presented in the instruction. Rather, they did also learn by deriving and constructing information left implicit in the instruction, relating this information to their pre-knowledge and possibly re#ning and modifying their pre-knowledge in those cases where con#icts became aware.

We live in an era when everyday activities are shaped by environments that are not only artificial—almost half of humanity lives in cities—but also mediated. Emotional and cognitive activities in all levels and segments of society are increasingly vested in information-rich venues supported by television, radio, telephone, and computer networks. Even in very remote areas, hunters and farmers watch satellite broadcasts and play battery-operated video games. And in the depths of the Amazon River basin, tribes use tiny video cameras to document territorial encroachments and destruction of rain forest habitat. 10.1 OVERVIEW This chapter explores the metaphor of media as lived environments. A medium can be considered an environment to the extent that it supports both the perception of opportunities for acting and some means for acting. This environmental metaphor can help us understand how media users exercise their powers of perception, mobility, and agency within the constraints

implicit knowledge about motion

The importance and growing awareness of domain knowledge acquisition in information systems development and, especially, in the process of design of human-computer interfaces, are becoming more evident. In several in-house development projects, methods for efficiently capturing and utilising domain knowledge have been defined and tested (e.g., through the definition of domain specific style guides and analysis of information utilisation). Also, methods for modelling case handling work in general terms, which is the main application focus of our studies, have been developed and tested in larger organisations. This paper focuses on the relation between domain knowledge models and conceptual models in information system development and user models in human-computer interaction. Based on Norman's model of user perception of an existing computer system, different limitations are identified and possible extensions are discussed. By introducing the domain context, several additional models of...

author at the Annual Dinner