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Older users generally take more steps than younger users in finding the same amount of information. For example, Meyer, et al. (1997) found that this occurs because older adults tend to revisit already viewed pages. Furthermore, Mead, et al. found that older users' success at finding information declined significantly when they had to follow more than 3 to 6 hyperlink paths to get to the desired information. It is believed this decline in performance occurs because older users tend to have greater trouble remembering their location within a site because of a decrease in working memory efficiency. Therefore, if the site is geared towards an older population it is especially important not to have a very deep hierarchy. It is also important that the site's contents be explicit at the beginning of the site (at the homepage level) instead of relying on exploration. This could be done by placing a site index or sitemap at the homepage level. It is also recommended to use clearly visible navigational aids to help them visualize the structure of the site. In another study, Groff, Liao, Chaparro, and Chaparro (1999) found that older users were slower than college-age users in finding information. In general, older users took the time to carefully read the text on a web page before continuing the tasks, which tended to slow them down. This finding is supported by the research of Youngs (1999) who found that older users tended to carefully read information before exploring, which further supports the idea of placing a site index at the homepage level. Older adults also prefer text to have very clear headings (see Hartley, 1994). Clear and large headings help orientate users as well as help those who have difficulty reading because of degraded or impaired vision by giving them obvious signposts. Usually the greatest factor affecting older web users is their decline in vision. For example, Weale (1961) stated that there is a 50% reduction in the amount of perceived light at age 50 compared to age 20, and this reduction increases to 66% at age 60. It is therefore recommended that all sites, but particularly those directed towards older users, have high contrast between the text and the background, as well as between darker and lighter colors in general. In addition, as lenses thicken, there is a reduction in the transmission of blue light through it. For this reason, older people have more trouble sorting or matching colors, and make more errors in the blue-green and red regions than in the other color regions. Fortunately, there are many resources available to help designers create websites that are accessible to degraded or impaired vision users. One of the better resources is the Web Accessibility Initiative (see in reference section). Older adults also tend to have a reduced field of view. Consequently, more important information and links should be placed closer to the center of the screen in order for them to be more easily detected (Hawthorn, 2000). This is particularly true if there are many objects on the screen. That is, older adults generally have trouble locating a specific object if there are many other objects on the screen (Plude & Hoyer, 1981), especially if the targeted object is located on the screen's periphery. Studied examining the reading performance of older adults have found that colored text on a colored background typically reduces their reading performance compared to reading black text on a white background (Charness & Bosman, 1990). Moreover, research has shown that dark text on light backgrounds is generally superior to light text on dark backgrounds (Tobas, 1987). However, older adults do have an increased sensitivity to glare. Thus, it is recommended that backgrounds not be pure white, but some form of off-white color (such as background presented here). Because of a general decline in acuity, the size of text within a site should also be larger (14-points or more). For example, older adults (mean of 70) have also been found to be more accurate, read faster, and prefer 14-pont font sizes (see Figure 1). They also tend to read faster with serif fonts (Bernard, Liao, & Mills, 2001)
Note:: an examination of font preference for children and older adults is discussed in the How should text be presented within a website link
Older adults have reduced attention spans. According to Vercruyssen (1996), older adults have difficulties in attention over long periods of time. For instance, Hawthorn (2000) suggests that older adults may be especially distracted by extraneous visual noise, such as background graphics. Other distractions may include such things that obscure the screen-even if it is only temporarily visible. Consequently, items such as pop-out ads and multiple windows may tend to distract and disorient them to a greater extent than younger adults.
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