Using Eye Tracking For Reading Studies

Dyslexia and web interaction: Seeing through dyslexics’ eyes Areej Al-Wabil, Panayiotis Zaphiris, Stephanie Wilson Centre for HCI Design, City University London

Overview
Dyslexia and web interaction
Exploratory study of web navigation: Strategies and personalised approaches
Investigating dyslexics’ visual search of web pages through eye tracking
March 11, 2008

What is dyslexia?
C ognitive difficulty with the written form of language
I ndependent of intellectual, cultural, and emotional causation
N eurobiological in origin, persistent condition
H ighly individual condition – combination of difficulties and abilities that affect people to varying degrees of severity
D ifficulties: reading, writing, spelling, auditory processing, visual processing, directional confusion, weakness in short term memory, organisation, sequencing, orientation
S trengths: Intuitive problem solving, creativity, good at visualisation, making links between things and seeing connections
March 11, 2008

How does dyslexia affect technology use? March 11, 2008 Akiyoshi Kitaoka, Rotating Snakes (2003). This picture by Kitaoka appears to move due to the luminance contrast between the black, blue, white, and yellow.

Visual processing difficulties March 11, 2008

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
March 11, 2008 SeeWord SpeakOut

Exploratory Study: Web navigation
Sense Making Methodology: User-centred approach to studying and understanding users and designing systems to serve their needs
March 11, 2008

Example 1 – Navigating within a web site
Consistent location of main navigation
Inconsistent navigation causes disorientation
Scrolling difficulties – visible navigation
Dynamic navigation
Sensitivity to cursor movements
Eye hand coordination / Dyspraxia
Overlapping text
Reading difficulties
Reduces onscreen complexity
Visual Processing
March 11, 2008

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 March 11, 2008

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
March 11, 2008

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.
March 11, 2008  Investigate the visual scanning of web pages by examining dyslexics’ visual attention and web exploration patterns through eye tracking. Image source: Tobii.com

How can eye tracking help my work?
User population
Difficulties in articulating their thoughts
Faulty eye movements
Causes of the problem are still debated by researchers
Attentional processes
Eye-mind hypothesis
Reliable measure of attentional mechanisms
March 11, 2008 Do Don’t do Diagonal of indecision Benefit of doing Cost of doing Low High High  Decision-plane model of the costs and benefits of using eye tracking in my study Adapted from (Rosenthal & Rosnow, 1984)

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.
March 11, 2008

Seeing through dyslexics’ eyes: Investigating dyslexics’ visual scan paths on the web
In depth observation study: compare eye movement behaviour of dyslexic and non-dyslexic users in their interaction with the web
The problem of how cognitive deficits associated with dyslexia affect web navigation is addressed in this investigation
March 11, 2008 Video: Gaze replay

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
March 11, 2008 Accessible Inaccessible Site Nav Info Task Experimental design

Dealing with data: preparation & recording March 11, 2008 Cognitive Profile

Preparing data for analysis March 11, 2008 Creating segments and defining scenes Creating filters and generating plots & maps

Design: Seeing through dyslexics’ eyes
Think-Aloud
Concurrent
Retrospective - with or without gaze replay
Care with movement
run through a task
Audio/Video capture
Annotating gaze replay
March 11, 2008

Do dyslexics exhibit distinctive web navigation behaviour?
March 11, 2008 Dyslexics Control Group

Example: Strategic search patterns
March 11, 2008 Dyslexics Control Group

Analysis: Dyslexics’ visual search
What are the dyslexic impairments that can cause functional difficulties specifically in relation to interacting with web navigation structures?
March 11, 2008 Gaze Plot Heat Map

Explore how dyslexic difficulties (e.g. weak short term memory) relate to behaviour and performance measures?
Analysis: Dyslexics’ visual search March 11, 2008 Direction of scanpaths, # of fixations Dwell time, spatial density of fixations Apply filter WeakMemory  Examine data

Analysis: Dyslexics’ visual search March 11, 2008 Export to statistical software packages Statistical analysis provided by Studio

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.
Participant set-up is important
Apply selectively to the right problems
Temptation to over interpret
Relating eye tracking metrics to cognition
March 11, 2008

Thank you Areej Al-Wabil, Panayiotis Zaphiris, Stephanie Wilson Centre for HCI Design, City University London, UK [email_address] [email_address] [email_address] March 11, 2008

Using Eye Tracking For Reading Studies

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