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Dyslexia and web interaction: Examining visual attention on web navigation structures with eye tracking Areej Al-Wabil, Panayiotis Zaphiris, Stephanie Wilson Centre for HCI Design, City University London
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Dyslexia and web interaction: Examining visual attention on web navigation structures with eye tracking
Areej Al-Wabil, Panayiotis Zaphiris, Stephanie Wilson
Centre for HCI Design, City University London
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Overview
Dyslexia and web interaction
Exploratory study of web navigation: Strategies and personalised approaches
Investigating dyslexics’ visual search of web pages through eye tracking
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What is dyslexia?
CCognitive difficulty with the written form of language
IIndependent of intellectual, cultural, and emotional causation
NNeurobiological in origin, persistent condition
HHighly individual condition – combination of difficulties and abilities that affect people to varying degrees of severity
DDifficulties: reading, writing, spelling, auditory processing, visual processing, directional confusion, weakness in short term memory, organisation, sequencing, orientation
SStrengths: Intuitive problem solving, creativity, good at visualisation, making links between things and seeing connections
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How does dyslexia affect technology use?
Akiyoshi Kitaoka, Rotating Snakes (2003). This picture by Kitaoka appears to move due to the luminance
contrast between the black, blue, white, and yellow.
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Visual processing difficulties
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Reading and writing difficulties
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Technology assistance
Dyslexia is a highly individual condition
Previous work has focused on interface design issues concerned with readability.
Navigating the web is affected by a range of issues beyond the readability of text
working memory order perception skills visual-spatial abilities
SeeWord: Gregor et al. (2003)
SpeakOut: Evans & Blenkhorn (2005)
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Sense Making Methodology: User-centred approach to studying and understanding users and designing systems to serve their needs
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Exploratory Study: Web navigation
Dervin, B. (1992). From the mind’s eye of the user: the sense-making qualitative-quantitative methodology.
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Example 1 – Navigating within a web site Consistent location of main
navigation Dynamic navigation
Sensitivity to cursor movements Eye hand coordination / Dyspraxia
Overlapping text Reading difficulties
Reduces onscreen complexity Visual Processing
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Most participants were not aware of their existence – even on sites they visit often
Were not perceived as useful aids exacerbate their difficulties too much information
‘I find those -pointing to sitemaps- difficult to look at… The text gets blurred and starts moving around. Sometimes I feel a bit of anxiety coming and I need to take a break.’
Example 2 – Sitemaps
April 2, 2008
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Exploratory study: Key findings
Dyslexics face many of the same problems that users experience on the web, but with greater severity and in some cases to a degree in which these problems inhibit access to web content (e.g. animations and sitemaps)
Dyslexic difficulties and strengths directly influence their search strategies on the web consistency in the design provide alternative aids
Despite the existence of many standards-conforming web sites, the web still suffers from many deficiencies in support for navigation, particularly for users with dyslexia
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Investigating the visual search of web pages
The exploratory study yielded results suggestive of the presence of patterns in scanning web pages by dyslexic users that may be different from typical web users.
Examine dyslexics’ visual attention and web exploration patterns through eye tracking.
Image source: Tobii.com
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What is eye tracking?
Attention deployment
Target processing
Visual search
Video of gaze replay
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Eye tracking: Seeing through dyslexics’ eyes
Eye movement researchers have used eye tracking devices to examine the visual scan path of dyslexics
It has been established that visual scan paths of dyslexics differ in reading and non-reading tasks
Dyslexic readers make longer fixations, more fixations, shorter saccades and more regressions than non-dyslexic readers.
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Seeing through dyslexics’ eyes: Investigating dyslexics’ visual scan paths on the web
The problem of how cognitive deficits associated with dyslexia affect web navigation is addressed in this study
Objectives:1. Gain insight into how dyslexics view web pages and make sense
of navigation structures on web sites
2. Formulate hypotheses about the effect of dyslexic cognitive impairments on web navigation
3. Empirically test hypotheses by examining dyslexic eye movements in navigation
4. Distil findings of the empirical investigation into a set of design implications for accessibility designers and researchers
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Eye tracking: Seeing through dyslexics’ eyes
User population Difficulties in articulating their
thoughts Faulty eye movements Causes of the problem are
not fully understood Attentional processes
Eye-mind hypothesisReliable measure of
attentional mechanisms
Do
Don’t do
Diagonal of in
decision
Benefit of doing
Co
st o
f d
oin
g
Low High
High
Decision-plane model of the costs and benefits of using eye tracking in my study
Adapted from (Rosenthal & Rosnow, 1984)
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Study design Data collection
Performance Measures Efficiency – time on task Effectiveness – number of errors
Process measures Fixations Attention switching Scan path similarity
User selection Representative sample Experimental and control groups
Task and Stimuli selection Navigation – ‘find a page..’ menus Informational – ‘find the contact number for..’ read/scan Exploration – free viewing memory
Accessible Inaccessible
Site
Nav
InfoT
ask
Experimental design
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Cognitive profiles and eye tracking
Cognitive Profile
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Preparing data for analysis
Creating segments and defining scenes Creating filters and generating plots & maps
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Design: Seeing through dyslexics’ eyes Audio/Video capture
Annotating gaze replay
Think-aloud protocol
Concurrent
Retrospective - with or without gaze replay
Care with movement
calibration
run through a task
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Analysis: Dyslexics’ visual search
What are the dyslexic impairments that can cause functional difficulties specifically in relation to interacting with web navigation structures?
Gaze Plot Heat Map
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Visual attention on web pages
Do dyslexics exhibit distinctive web navigation behaviour?
Dyslexics Control Group
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Design: Seeing through dyslexics’ eyes
Example: Strategic search patterns
Dyslexics Control Group
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Explore how dyslexic difficulties (e.g. weak short term memory) relate to behaviour and performance measures?
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Analysis: Dyslexics’ visual search
Direction of scanpaths, # of fixations Dwell time, spatial density of fixations
Apply filter WeakMemory Examine data
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Analysis: Dyslexics’ visual search
Export to statistical software packagesStatistical analysis provided by Studio
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Final notes
Performance data does not always tell the whole story. Eye movements provide a more complete picture of interaction by filling in the gaps between observable events.
Relating eye tracking metrics to cognition. Temptation to over interpret
Distil findings of this empirical investigation into a set of design implications for accessibility designers and researchers
April 2, 2008
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Thank you
Areej Al-Wabil, Panayiotis Zaphiris, Stephanie Wilson
Centre for HCI Design, City University London, UK
Presentation: http://www.slideshare.net/areejalwabil/brighton
