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Adaptive control of thought-rational (ACT-R; J. R. Anderson & C. Lebiere, 1998) has evolved into a theory that consists of multiple modules but also explains how these modules are integrated to produce coherent cognition. The perceptual-motor modules, the goal module, and the declarative memory module are presented as examples of specialized systems in(More)
Understanding the interaction of a user with a designed device such as a GUI requires clear understanding of three components: the cognitive, perceptual and motor capabilities of the user, the task to be accomplished and the artefact used to accomplish the task. Computational modeling systems which enable serious consideration of all these constraints have(More)
Systematic errors in performance are an important aspect of human behavior that have not received adequate explanation. One such systematic error is termed postcompletion error: a typical example is leaving one's card in the automatic teller after withdrawing cash. This type of error seems to occur when people have an extra step to perform in a procedure(More)
Postcompletion errors, which are omissions of actions required after the completion of a task's main goal, occur in a variety of everyday procedural tasks. Previous research has demonstrated the difficulty of reducing their frequency by means other than redesigning the task structure [Byrne, M. Task structure and postcompletion error in the execution of a(More)
Click-down (or pull-down) menus have long been a key componentof graphical user interfaces, yet we know surprisingly little abouthow users actually interact with such menus. Nilsens [8] study onmenu selection has led to the development of a number of models ofhow users perform the task [6, 21. However, the validity of thesemodels has not been empirically(More)
In the United States, computer-based voting machines are rapidly replacing other older technologies. While there is potential for this to be a usability improvement, particularly in terms of accessibility, the only way it is possible to know if usability has improved is to have baseline data on the usability of traditional technologies. We report an(More)
Users faced with Web sites containing many possibly relevant pages often have a decision to make about navigation: use the menu of links or use the provided site search function. Two studies were conducted to examine what users do when faced with this decision on e-commerce Web sites, and how users go about deciding which method to attempt. An exploratory(More)
Because of the visual nature of computer use, researchers and designers of computer systems would like to gain some insight into the visual search strategies of computer users. Icons, a common component of graphical user interfaces, serve as the focus for a set of studies aimed at (1) developing a detailed understanding of how people search for an icon in a(More)
OBJECTIVE To replicate a successful laboratory slip-class error paradigm and, more importantly, to further understand the underlying causes of errors made in that paradigm. BACKGROUND Routine procedural errors are facts of everyday life but have received limited controlled empirical study, despite the sometimes severe consequences associated with such(More)