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© 1997 Copyright on this material is held by the authors.
Several types of age-related declines could impede older WWW users. The literature describes a decline in working memory; it shows that systems that make users remember items from one task to another are less usable for older adults [1]. Thus, older WWW users could have trouble remembering which pages they have seen, or how they arrived at the current page. Further, increased age is associated with increased motor noise and slower movements [3]. This could affect the use of scroll bars or image maps. More positively, research has shown cognitive adaptability in older adults [4]. So, they may respond well to training in complex tasks. With proper design and training, older adults can learn to navigate the WWW.
We studied both younger and older adults, in two different training conditions, as they learned to find specific information in a web site. Our observations suggest that interventions, including navigation aids and training, could help both younger and older WWW users to find the information they need.
To perform the search tasks, participants used Netscape Navigator (v. 2.0), running under Microsoft Windows (v. 3.1), to browse a set of 19 related web pages. The files were stored on the hard drive of a personal computer, to keep control over the material that participants could see. The content was taken with permission from the Scientific American WWW site [2].
The site included a home page, two articles with links to supplemental pages, several articles without such links, a page of article summaries and links, and two navigation aids that could be used to reach any page (a "site map" and a "table of contents"). Most search targets were within articles and their supplemental pages; one was on the home page. Some pages also included "index tabs," labeled buttons at the top of a page that linked directly to important pages (and were highlighted to indicate the current page).
After the first task, participants started each search from the end point of the previous search. We presented the nine tasks in the same order to each subject. This allowed us to compute the shortest possible path lengths for each task. Participants had 10 minutes to complete each task.
We logged all movements between and within pages. We also asked participants to "think aloud" while searching, conducted exit interviews, and audio recorded the session.
Also, in both age groups, participants with the "hands-on" tutorial seemed slightly more efficient than those without this training. Across age groups, subjects with the "hands-on" training took 7.8 steps on average to find a target, as opposed to 9.3 for those without this training.
Older participants were more likely than younger ones to return to the home page as the first step in a search. Younger participants did this in less than 15% of searches, but trained older subjects did in 23% of their searches, and the figure for older subjects without the training was a big 37%. Several targets were only a link or two away from the endpoint of the prior search, such that returning "home" was often a move away from the target. So this strategy of returning to the home page reduced the older subjects' search efficiency. However, it may also have avoided the need to remember precisely where they had gotten when they had finished the previous search.
Also, older participants were more likely than younger ones to return to pages that they had already visited within the same search task. The average younger participant did this about 6 times during the entire set of tasks, while the average older participant did this almost 19 times. The older users may have had problems remembering which pages they had visited and what was on those pages.
Training seemed to affect users' preferences. Overall, participants with the interactive training used the "Back," "Forward" and "Home" buttons on the Netscape browser for a greater percentage of actions (26% vs. 20%). For the younger users, the trained group used the scroll bar but not the keyboard to move within a page (42% of actions vs. 0%), while the group without the training used the keyboard for a greater proportion of actions than the scroll bar (27% vs. 20%). A similar interaction for the older groups was less pronounced. The trained older subjects did use the keyboard to move within a page for 8% of their actions, perhaps because the precise movements required by the small scroll bar controls were harder for them.
Older participants used "index tabs" more than younger ones (9% of actions vs. 3%), and those who had the training more than those who did not (26% vs. 6%). Also, the only group to significantly use the site map was the older trained group. The training may have encouraged the older adults to take advantage of the site map. However, the younger people (even with the training) may not have felt a need to consult the site map, given their efficiency.
There are some possibilities for addressing these problems. For example, interactive training on the navigation methods seems to reduce the need to start most searches from one home page. However, it also appears that older users need some better means of seeing where they are and where they have been, rather than constantly having to keep track of this themselves. In future work, we will discuss more specific design features to address these problems. Without them, information on the WWW could be effectively inaccessible to a major segment of the population.
2. Scientific American. Available online as http://www.sciam.com/.
3. Walker, N., Philbin, D.A., and Spruell, C. The use of signal detection theory in research on age-related differences in movement control. In Aging and Skilled Performance, W.A. Rogers, A.D. Fisk, and N. Walker, Eds. Lawrence Erlbaum Associates, Mahwah, NJ, 1996, pp. 45-64.
4. Willis, S.L. Improvement with cognitive training: Which old dogs learn what tricks? In Everyday cognition in adulthood and late life, L.W. Poon, D.C. Rubin, and B.A. Wilson, Eds. Cambridge University Press, Cambridge, MA, 1989, pp. 545-572.
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