Cognitive Accessibility of Information in Interactive Systems

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The cognitive walkthrough (CW) is a usability inspection method aimed at evaluating the ease of learning cognitive artifacts such as computer software. The latest version, much simplified from its predecessor, was still difficult to apply to real-life environment because without background in cognitive psychology and usability evaluation it would be difficult for analysts to understand what exactly they were supposed to evaluate. The difficulty may partly be due to the granularity mismatch between what CW questions address and what analysts are likely to look for. We suggest that such granularity mismatch be alleviated if CW questions are generated based on a proper model of human-computer interaction (HCI). In this project, we extended Norman's HCI model by incorporating such distinctions as "object versus action" and "perceiving versus understanding" and then proposed an Extended Cognitive Walkthrough (ECW) whose questions explicitly address the ease of identifying correct objects/ac … More tions and of perceiving/understanding them. A comparative evaluation of the latest CW and our ECW indicated that those newly-introduced distinctions could make the CW easier to conduct and more effective in identifying usability problems.In addition, we confirmed that with a software tool developed for the online ECW evaluation, persons with disabilities were able to conduct the ECW for Web sites remotely at their own location without requiring them to be in a usability laboratory. Although testing with users is widely acknowledged as an effective way of identifying design problems that may otherwise be overlooked by even evaluation specialists, it is also recognized that recruiting appropriate participants often becomes problematic for user testing. A particular challenge for testing with persons with disabilities is that depending on the types and degrees of their disabilities it can be extremely difficult, if not impossible, for them to come away from home to participate in user testing. The ECW results were insightful and valuable as they were first-hand judgments of the persons with disabilities, reflecting their particular needs arising from individual disabilities. Less