Steve J. Westerman

Mapping semantic information in virtual space

This paper reports two studies investigating the computer-based representation of the semantic information content of databases using object location in two- and three-dimensional virtual space. In the first study, the cognitive demands associated with performing an information search task were examined under conditions where the “goodness of fit” of the spatial-semantic “mapping” was manipulated. The effects of individual differences in spatial ability and associative memory ability also were considered. Results indicated that performance equivalence, between two- and three-dimensional interfaces, could be achieved when the two-dimensional interface accounted for between 50 and 70% of the semantic variance accounted for by the three-dimensional solution. A second study, in which automatic text analysis was used to generate two- and three-dimensional solutions for document sets of varying sizes and types, supported the conclusion that, for the purpose of information search, the amount of additional semantic information that can be conveyed by a three-dimensional solution does not outweigh the associated additional cognitive demands.

Age and cognitive ability as predictors of computerized information retrieval

Abstract This paper presents an empirical investigation of age and cognitive ability as predictors of computerized information retrieval. Upon the basis of age-related changes in cognitive ability, hypotheses were generated relating to the effects of database structure (linear, hierarchical, or network) and node selection method (explicit or embedded menu). In keeping with previous research in other areas of human-computer interaction, there was a significant main effect of age, with older subjects performing more slowly. However, interactive effects of ‘question block’ indicated that older subjects were at a particular disadvantage in the early stages of task performance. Age differences in processing speed and/or psychomotor skill appeared to be a particularly important factor. Whilst the effects of cognitive ability were generally weak, spatial memory and logical reasoning scores were negatively correlated with information retrieval response times. Although interactions were not significant, trends in ...

Individual Differences in the Use of Command Line and Menu Computer Interfaces

This article presents an experimental investigation of the process of computer-based command generation. The comparative cognitive demands imposed by menu and command line interfaces are examined in relation to individual differences in expertise and cognitive ability. Three-way interactions between associative memory, expertise, and command generation method indicated similarities in the performance of expert participants with low associative memory and that of novices. Spatial memory also interacted with expertise, with novices with low spatial memory performing more poorly than any other group. Implications for interface design are considered.

Cognitive ability and information retrieval: When less is more

This paper is concerned with the use of virtual environments as a means of conveying semantic information relating to the contents of computerised textual databases. two empirical studies are reported that investigated the influence of individual differences in cognitive ability on search task performance. In the first experiment, objects (each representing a type of animal) were placed ordinally in a three-dimensional cube arrangement based on ratings of semantic similarity. Participants were required to locate a series of randomly selected objects. Contrary to prediction, participants with high associative memory were comparatively poorer performers. In a second experiment ‘true’ rating distances were used to locate objects in virtual space. High spatial ability was associated with better performance and, in contrast with the results of Experiment 1, this pattern also was replicated for associative memory. Implications are discussed.

Evaluation of Affective Interactive Applications

Methods are developed for different audiences and purposes. HCI researchers develop methods to shape the future through pure, applied and blue sky research – as is still the case with most affective interactive applications. Unsurprisingly, practitioners will be more concerned that the methods they use not only are tractable but produce better and more innovative results in terms of the systems they ultimately release into the world. Researchers, on the other hand, may have other concerns, such as the novelty of their techniques. Up until recently, most HCI methods (both for researchers and practitioners) were developed for work applications and desktop situations. They focused on efficiency, learnability, transparency, control and other work-related values. They were developed in response to a theoretical orientation which viewed the user as an information processing system not so dissimilar to the computer itself. But now that HCI is concerned with technologies that enter all aspects of life, our methods have begun to change and will need to continue to change. In keeping with our changing conception of what a “user” is and a wider concern with their experience of use of new technologies, a key challenge will be to develop and expand methods for analyzing not just what people do with the technology but how it makes them feel, and not just how people understand technology but how they make sense of it as part of their lives. Methods must be concerned, not only with issues of usefulness and usability, but also with issues of aesthetics, expression, and emotion. In addition we need to focus on evaluating technology not just in the short term under controlled conditions but also in the longer term and in broader social and cultural contexts. In this section, we will therefore provide two strands of evaluation methods. The first concerns what we might see as more traditional usability evaluation: is my system usable for the purpose it was designed for? The second strand tries to get at what we have named “third wave of HCI” in the previous chapters: does my system provide for the kind of (emotional) experience that it aimed to do?