Catálogo de publicaciones - libros

This paper describes a study that examines the amount and kinds of usability and challenge problems, which can be found during initial and extended use of children’s computer games. On the one hand the amount of problems might decrease over time, because users become more experienced. On the other hand, new errors may occur during extended use because users start making more errors related to increased carelessness. We discuss the chances of finding problems and relative importance of problems found during formative evaluations of initial and extended use of children’s computer games.

An experimental comparison of interaction in the real world and a CAVE virtual environment was carried out, varying interaction with and without virtual hands and comparing two manipulation tasks. The double-handed task was possible in the real world but nearly impossible in the VE, leading to changed behaviour. The single-handed task showed more errors in the VE but few behaviour differences. Users encountered more errors in the CAVE condition without the virtual hand than with it, and few errors in the real world. Visual feedback caused many usability problems in both tasks. The implications for VE usability and virtual prototyping are discussed.

Bookmarks are a valuable webpage re-visitation technique, but it is often difficult to find desired items in extensive bookmark collections. This experiment used response-time measures and eye-movement tracking to investigate how different information structures within bookmarks influence their salience and recognizability. Participants were presented with a series of news websites. The task following presentation of each site was to find the bookmark indexing the previously-seen page as quickly as possible. The Informational Structure of bookmarks was manipulated (top-down vs. bottom-up verbal organizations), together with the Number of Informational Cues present (one, two or three). Only this latter factor affected gross search times: Two cues were optimal, one cue was highly sub-optimal. However, more detailed eye-movement analyses of fixation behaviour on target items revealed interactive effects of both experimental factors, suggesting that the efficacy of bookmark recognition is crucially dependent on having an optimal combination of information quantity and information organization.