Mathematical Modeling of Age Differences in Hierarchical Navigation Systems
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Transcript of Mathematical Modeling of Age Differences in Hierarchical Navigation Systems
Wayne State UniversityInstitute of Gerontology
Panayiotis ZaphirisIndustrial and Manufacturing Engineering Dept.
Institute of GerontologyWayne State University
Detroit, MI
Older Adults and the World Wide Web
Wayne State UniversityInstitute of Gerontology
Know the User
• Seniors are the fastest growing group on the internet.
• 25% of seniors with computers are online
• 70% are using their computers daily [Morris, D. C. (1996)].
• Important to develop age-friendly web pages.
Wayne State UniversityInstitute of Gerontology
Why
• The World Wide Web is not (should not be) just for young people !
Wayne State UniversityInstitute of Gerontology
Today’s Presentation
• What attracts elders to the internet ?
• What changes with aging ?
• Web Design and Aging - Guidelines ?
• Search Engines (case study)
• Depth Vs Breadth (an other issue)
Wayne State UniversityInstitute of Gerontology
What Attracts Elders to the Internet?
• Connectivity– Chat online with
friends and family– Express their opinions– Feel less socially
isolated– Start second careers– Research health issues
Wayne State UniversityInstitute of Gerontology
What Attracts Elders to the Internet?
• Self-paced Environment
• Dynamic and Interactive– The web can become a means of socializing and
maintaining contact with the outside world (especially for older adults suffering from loneliness, feelings of isolation and depression)
• Anonymity
Wayne State UniversityInstitute of Gerontology
What changes with Aging?
• Vision– Size of field of vision may diminish– Difficulty in following fast moving objects.– Many experience short-sightedness – Changes in perception of color
Wayne State UniversityInstitute of Gerontology
What changes with Aging?
• Cognitive– Some older adults have slower response times– May have difficulty performing multiple tasks
(especially new ones)– Less able to ignore irrelevant stimuli (eg.
Banner advertisements)– Decline in spatial abilities.
Wayne State UniversityInstitute of Gerontology
What changes with Aging?
• Hearing– Hearing loss or diminishment.– Problems hearing high frequencies and in
distinguishing speech.
• Motor Skills– Small movements or finite mouse control can be
troublesome (especially for people suffering with arthritis).
Wayne State UniversityInstitute of Gerontology
Guidelines - Layout
• Layout– Large areas of white space and small blocks of
text increase readability.– Keep layouts and the interface similar from page
to page and make sure all the important navigation elements stay consistent.
– Don’t limit window size of your pages
Wayne State UniversityInstitute of Gerontology
Guidelines - Style
• Style– Choose fonts based on their legibility– Avoid colors that are exceptionally bright or
vibrant.– Animation or any quickly flashing or blinking
elements or banners are highly distracting.– Make all graphical links and buttons large and
easy to click on.
Wayne State UniversityInstitute of Gerontology
Guidelines - Color• Color
– Use color effectively– Pick colors from opposite sides of the color
wheel– Avoid combinations of blue - yellow and red -
green.
Wayne State UniversityInstitute of Gerontology
Guidelines
• Contrast– Greatest contrast exists between black & white.– View your pages on a black and white monitor
• Font– Larger type is easier to read. Twelve to fourteen
points is good font size for seniors.– Don’t limit ability to set his/her own font.
• Accessibility
Wayne State UniversityInstitute of Gerontology
Depth Vs Breadth
• Depth vs Breadth trade-off is a hot topic in menu selection.
• Depth seems to be the driving force in reaction time.
• Previous research has shown that previous studies on menu selection apply to web hierarchies.
Wayne State UniversityInstitute of Gerontology
Previous Research
• Analytical models– Lee and MacGregor (1985)– Paap and Roske-Hofstrand (1986)
• Empirical studies– Numerous menu related breadth vs depth– Very few web related (but replicate menu related
studies).
Wayne State UniversityInstitute of Gerontology
Lee MacGregor modelFor Exhaustive Search: TE
b d d b t k c( )
For Self-Terminating Search TSb d d
b 1( ) t
2k c
Where
TE and TS represent task completion timesd = depth of link/menu hierarchyb = breath of link/menu hierarchyt = time to read or process one optionk = human response timec = computer response time
Wayne State UniversityInstitute of Gerontology
Proposed Modified Model
For Exhaustive Search - Aging: TEAb d d b a1 t a2 k c( )
For Self-Terminating Search - Aging: TSAb d d
b 1( ) a1 t
2a2 k c
Where a1 and a2 are age related parameters.
Wayne State UniversityInstitute of Gerontology
Sample contour plots•Young users with t = 0.25, k = 0.5, c = 0.5•TE = Exhaustive, TS = Self - terminating searching
TE
2 4 6 8 10
2
4
6
8
10
25
20
20
15
15
15
10
10
10
55
5
5
TS
2 4 6 8 10
2
4
6
8
10
15
15
10
10
10
55
5
5
Wayne State UniversityInstitute of Gerontology
Sample contour plots•Seniors with t = 0.25, k = 0.5, c = 0.5•TEA = Exhaustive, TSA = Self - terminating searching (aging)TSA
b d db 1( ) a1 t
2a2 k c
TEA
2 4 6 8 10
2
4
6
8
10
3530
25
25
20
20
20
15
15
15
1010
10
10
5
5
5
TSA
2 4 6 8 10
2
4
6
8
10
25
20
20
15
15
15
10
10
10
55
5
5
Wayne State UniversityInstitute of Gerontology
28.205
8.75
TEb 5
TSb 5
TEAb 5
TSAb 5
101 b
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 108
10
12
14
16
18
20
22
24
26
28
30Plot of Times versus breadth
breadth
Tim
es
Wayne State UniversityInstitute of Gerontology
39.385
2.25
TE5 d
TS5 d
TEA5 d
TSA5 d
101 d
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 100
5
10
15
20
25
30
35
40Plot of Times versus depth
depth
Tim
es
Wayne State UniversityInstitute of Gerontology
Optimization Results
k tE EA S SA E EA S SA
0.5 0.25 6 6 8 8 7 6 10 100.5 .5 4 4 6 6 5 5 7 70.5 1 4 4 5 5 4 4 6 60.5 2 3 3 4 4 3 3 5 51 .25 7 7 10 10 8 8 12 121 .5 5 5 7 7 6 6 8 81 1 4 4 6 6 4 4 6 61 2 3 3 5 5 4 4 5 5
c=0.5 c=1.0
Results being the optimum number of items per screen. E = Exhaustive, S = Self terminating, EA = Exhaustive aging, SA = Self terminating aging.
Wayne State UniversityInstitute of Gerontology
Further research
• Structural Equation Modeling to more accurate measure the aging factor in information retrieval and searching on the web.
• Usability testing and participant observation.
• Surveys.
Wayne State UniversityInstitute of Gerontology
Conclusions
• Sensitivity to age related differences and web design.
• Web should be as universal and accessible as possible for people of all ages.