1

Population Diversity and Universal Accessibility

Jinjuan Feng

Overview Universal accessibility

Definition Dimensions

Three categories of human capabilities Physical capabilities Perceptual capabilities Cognitive capabilities

Human capabilities according to age General design guidelines for universal

accessibility

Universal accessibility (UA) How can information and communications services

be made accessible for every citizen? Seniors and children People with disabilities Experienced users versus novice users

Time wasted on computer: 5.1 hour/week

Access to computer and internet

Accessibility does not equal to usability

Dimensions of UA Human capabilities

Physical Perceptual Cognitive

Age

Context of use

Physical abilities

Physical abilities refers to functions achieved by human motor system, mainly affects the ability of inputting data to the computer

Physical abilities that affect computer users mainly relate with finger, hand and arm

There is no average user, either Compromises or multiple versions of a system

Physical measurement of human dimensions not enough, must also consider dynamic measures:

reach, strength speed

Cognitive abilities

The human ability to interpret sensory input rapidly and to initiate complex actions

Classification of human cognitive processes:•Long-term and semantic memory•Short-term and working memory •Problem solving and reasoning •Decision making and risk assessment•Language communication and comprehension •Search, imagery, and sensory memory•Learning, skill development, knowledge acquisition and concept attainment

Perceptual abilities Functions achieved by human perceptual

systems, mainly affects the ability of receiving the data output by the the computer

Variances of the user population's sense perception

Vision: Touch: keyboard and touchscreen sensitivity Hearing: audio clues must be distinct

Cognitive and perceptual abilities

Factors affecting perceptual and motor performance:•Arousal and vigilance•Fatigue and sleep deprivation•Perceptual (mental) load•Knowledge of results and feedback•Monotony and boredom•Sensory deprivation•Nutrition and diet•Fear, anxiety, mood, and emotion•Drugs, smoking, and alcohol•Physiological rhythms

But note, in any application, background experience and knowledge in the task domain and the interface domain play key roles in learning and performance

Group Exercise:Personal Differences Work individually, write down as

many as perspectives that humans are different from each other

E.g. gender, race, hair color…

Among them, mark those that affect the use of computers

Personality differences

There is no set taxonomy for identifying user personality types

Designers must be aware that populations are subdivided and that these subdivisions have various responses to different stimuli

Myers-Briggs Type Indicator (MBTI) extroversion versus introversion sensing versus intuition perceptive versus judging feeling versus thinking

Designing for users with disabilities

Users with cognitive disabilities

Cognitive impairments (CI) IQ: 100 is average. 70 to 130 is considered normal.

People with IQ of below 70 may have mild to severe mental retardation

Relationship to security CI may hinder the users’ ability to understand and

learn security and privacy mechanisms and procedures

CI would affect the use of S&P mechanisms that require memory and recognition(e.g., password, CAPTCHA).

Users with cognitive disabilities

Interface design considerations Attention Memory loss and dementia Visuospatial, Iconic, and verbal abilities

Technologies to improve interaction Software to prompt communication for non

speaking people Software supporting dementia

Users with physical disabilities

Physical disabilities Health-condition induced PIs: Mainly injuries or

diseases affecting hands or arms SCI, RSI, ALS, etc.

Dimensions of PI Permanent or temporary Continuous or intermittent Progressive, regressive, or static Severity of PI

Users with physical disabilities

Physical disabilities affect the ability to interact with S&P applications, such as entering passwords. Existing S&P applications are not adapted to the possible alternative input techniques.

Technologies to improve interaction Keyboard and mouse modification Multi-Modal Speech recognition Head mounted devices Eye tracking Electrophysiological technology

Users with perceptual disabilities

Perceptual disabilities Visual function impairments affect computer usage profoundly

Visual acuity Contrast sensitivity Visual field Color vision

Auditory impairments Conductive or sensorineural Congenital, prelingual or postlingual Can affect learning and speech

Speech impairments Can affect interaction ability, especially in ubiquitous

computing environment

Demo: Effect of Red-Green Color Blindness

Users with perceptual disabilities

Technologies to improve interaction Perceptual interfaces

Multimedia interfaces Multimodal interfaces

Adaptive interfaces Synthetic and digitized speech Nonspeech sounds Auditory icons

Group exercise

If you are designing a website for the national federation of the blind, what special concerns should you take care of?

What is the challenge of designing a online tutoring database course for blind users?

Comments to exercise National Federation of the Blind

Limit the use of images, graphics, and animations

Make sure all image and links are accompanied with text

Online database tutor course How to deliver diagrams to the blind users

Audio interpretation Tactile interaction

Elderly Users

Higher percentage and wider needs 65 years or older: 13% in 2000, 20% by 2030 Wider needs: work, home, health care

As people age, all three types of human capabilities gradually decrease, affecting their ability to use S&P applications. Sensory processes Motor skills Cognitive abilities

Elderly Users

Designing for elderly users Hardware considerations

Display screen Keyboard Instructions and manuals

Input devices Keyboard and mouse Pen and touch screen, etc.

Software considerations Easy to learn Cognitive demand

Group exercise

Suppose you are asked to design a website for a senior living community, what will you do to fit the need of the elder users? Perceptually Cognitively Physically

Comments to exercise Perceptual

Maximize the contrast between characters and screen background Avoid small targets and characters Highlight important screen information Avoid color discriminations among colors of the same hue

Cognitive Minimize irrelevant screen information Present screen information in consistent locations Clearly label keys and icons Use icons that are easily discriminated and meaningful Avoid complex command languages

Physically Limit the number of icons on screen Maximize the size of the icons Increase the distance between those icons

Design for children How are children different?

Dexterity Motor control Physical size

Speech Prefer speech recognition than

typing

Design for children Reading

Reading level Font size

Background knowledge

Interaction style Easily distractible Use computer as a group

Security & Privacy for Children Due to the cognitive and mental capabilities,

children are particularly vulnerable to security and privacy violations.

Children may not be able to understand the need for S&P mechanisms and procedures

Children have problem learning and using many S&P applications due to limited reading and typing skills, as well as memory capabilities

30

Situationally induced impairments

Situationally-induced impairments refers to loss of functionality due to specific situations

Situationally-induced impairments are becoming more important with the popularity of mobile computing

Group exercise Think of three examples of situationally-

induced impairments that affect people’s Physically capabilities Perceptual capabilities Cognitive capabilities

For each example, discuss the specific body functions affected the type of tasks affected

Comments to exercise Physical capabilities

Walking, in a car driving on a pumpy road, cold weather, noise

Key in data using a PDA, entering data using speech recognition

Perceptual capabilities Noise Listening to the phone

Cognitive capabilities Using mobile phone driving

General design guidelines Designers must plan early to

accommodate users with disabilities

Early planning is more cost efficient than adding on later

Businesses must comply with the "Americans With Disabilities" Act for some applications