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Article Excerpt
INTRODUCTION
The Internet has sparked a revolution in the last decade, producing significant changes in the ways companies do business and individuals perform their daily tasks. Although the first "boom" of prosperity for new Internet businesses ended with the 1990s, its popularity and use show no sign of abating. As the frequency of Internet use and the number of individuals using it increase, it will become more important for the medium to provide information in an efficient and usable manner. This is especially true for older adults, whose needs and capacities differ significantly from those of younger users.
Currently, older adults constitute the fastest growing Internet user group (Lindberg, 2002; Morrell, 2002; Silver, 2001). One factor that may explain this trend is the aging population. It has been estimated that by 2030 there will be 70 million older Americans, roughly twice as many as there are today (Wetle, 2002). As this population grows, so too will the number of older adults using the Internet.
The Internet provides a number of benefits for older adults. It is used as a means of communication via E-mail, chat rooms, discussion groups, direct messaging, and so forth. A SeniorNet Survey on Internet Use (2002) reported that 94% of seniors who use the Internet do so to stay in touch with friends and relatives. The Internet also contains a wealth of medical information that can be particularly useful for the older adult when health becomes a greater issue and concern. According to the same SeniorNet survey, 70% of senior Internet users gather health information on line. Current news and events was the only other category that at least 70% of seniors indicated they access via the Internet. Going on line has also been shown to improve health and well-being (Lansdale, 2002).
A common use of the Internet is navigation of the World Wide Web (WWW), an Internet facility that links documents (i.e., Web pages) remotely and locally in hypertext forms (Nielsen, 2000). Compared with younger users, older adults experience more frequent problems using the WWW, including difficulty finding broken links, viewing graphics, finding new information, and revisiting pages or sites (Graphic, Visualization, and Usability Center [GVU], 1998). Thus, although older adults are generally willing and able to use computers, they, often have more problems than do their younger counterparts (see also Czaja & Lee, 2001).
The most common affordances used to facilitate Web search and navigation are graphical and text links. Graphical links are as varied as the needs and creativity of developers allow. In contrast, text links are constrained visually by the nature of the alphabet and semantically by linguistic convention. Also, standards exist to ensure text links have common characteristics. Often they are presented in blue, underscored type, are segregated by function from other page information, and can be given a color change (often to a short-wavelength violet or purple) once accessed to indicate their previous use. In principle, these conventions allow users to search and navigate the Web more easily,, but relatively few studies have systematically examined the effects of link characteristics on Web performance, and this is particularly true for older adults.
The purpose of this study was to examine some of the characteristics of links on Web pages that influence search. We chose to focus on Web pages for three reasons. First, data have shown that the WWW is the most frequently used Internet facility (GVU, 1998). Second, difficulty with navigation is one of the largest problems for WWW and hypertext users and is characterized by problems in searching for information and in getting lost while navigating (Conklin, 1987; Hammond & Allinson, 1989: Kim & Hirtle, 1995; Nielsen, 1990; Vora & Helander, 1997). Third, older adults consistently demonstrate poorer performance in visual search (see Madden & Whiting, 2003) and on many computer tasks (Czaja & Lee, 2001: Kelly & Charness, 1995) and thus may be more susceptible to problems while conducting WWW searches.
One of the more critical features influencing Web navigation is link salience. In the present context, salience refers to the conspicuity (Engel, 1971) of the links, which is influenced by a number of factors, including relative size, color, and contrast. Because enhancing salience increases the probability of quickly and easily isolating relevant information, high-salience targets mitigate the interfering effects of nontarget information (Scialfa, Esau, & Joffe, 1998: Treisman & Sato, 1990; Wolfe, 1994; Wolfe, Cave, & Franzel, 1989). A time-honored means of increasing the salience of text material is to vary print size. Changing the print size of links can ease search by allowing the links to segregate more easily from other text (Hartley, Trueman, & Burnhill, 1979). Additionally, increased text size can improve reading speed through the well-known relation of acuity demands to reading ease (Aberson & Bouwhuis, 1997). Typesetters have, for example, used changes in print size to indicate subsections of text (Hartley & Jonassen, 1985), and Bernard, Lida, Riley, Hackler, and Janzen (2002) have shown that when participants read on-line documents, 10-point fonts were read significantly more slowly than fonts at the 12-point size. Because changing print size is easy to implement, it is a prime candidate for improving the usability of a Web site.
Improving link salience via increased print size has special significance for older adults. The presenting acuity of older adults is often poorer than that of younger Web users (Gittings & Fozard, 1986), and their limitations in spatial vision are exacerbated when the glasses they wear are not designed for the distance and gaze angle of their workstations. As a consequence, reading speed and accuracy are reduced and visual fatigue is move likely. Although increased print size does not eliminate the blur that results from inappropriate optical correction, it does reduce the effects of blur by lowering the spatial frequency of the material. Thus one would expect older adults to benefit from increased print size (Echt, 2002). In addition, because older adults have deficits in both texture segmentation (Scialfa & Hamaluk, 2001; Scialfa, Hamaluk, Skaloud, & Pratt, 1999) and search for targets with low salience (Scialfa et al., 1998), larger print might help them in the initial localization of target links.
Location also plays a role in visual search. People find things most easily when the items are in a consistent and expected location that is near the point they are fixating or attending. For example, Theeuwes (1996) reported that visual search for roadway signage was carried out more quickly and with fewer eye movements when the target signage was in expected locations. Eccentricity effects are quite common in visual search (Scialfa & Joffe, 1997; 1998; Owsley, Ball, Sloane, Roenker, & Bruni, 1991), although the effects can be reduced through practice (Scialfa & Joffe, 1998). In addition, many attentional paradigms have shown that information is processed best when it is near the current focus of attention (see Madden & Whiting, 2005; McDowd & Shaw, 2000).
For English-language readers, eye movements and attentional allocation follow a canonical scanpath that is dictated by the written language, starting in the upper left and reading rightward until the end of the print line. At that point a large-amplitude saccade brings the reader to the beginning of the next line (Rayner, 1978). Thus targets in the upper left are much more likely to be found quickly (Megaw & Richardson, 1979), and information processing shows a bias to the right of the current fixation, most likely because attentional allocation is needed to facilitate saccades (Vitu, 1991). Oculomotor and attentional dynamics in Web-based search are complicated by the facts that less systematic scanning and browsing are often interspersed with reading (Nielsen, 2000), that Web material has a higher concentration of nontext material than prose does, and that information does not follow the relatively blocked format that is common with the printed word. Still, location effects can be seen in Web search. For example,...
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