2. ADAPTING TO VISUAL IMPAIRMENT
Before turning to the specific area of web environments, it is useful to review briefly the development of navigational and other aids for use in the everyday life of people with visual impairments. This gives some hints of the kinds of strategy that are adopted in the face of other access challenges, but it is also useful because very often web designers use spatial metaphors which may or may not translate well into non-visual approaches.
How do people who have been blind since birth navigate their way around a room or a building? Is it possible for a blind person standing in the middle of a large open town square to perceive that feeling of space? Or, if they have been taken on a specific route, perhaps to school or to work, are they then able to hold a mental picture in their mind of that route and if so, would it resemble the mental map of a sighted person? These questions were explored by Dodds et al. (1982) who undertook a series of tests with congenitally blind (i.e. blind from birth) children and with children who had become blind since birth. The tests attempted to explore previous theories relating to spatial representation and whether someone who has no visual experience can develop an idea of space.
Each child was taken on a specific route and then asked to draw a representative map of that route. The tests revealed that the children who had become blind (and therefore possessed some previous visual experience) could produce a more realistic map of the route taken - in other words one that resembled the actual route, whereas the children who were born blind had to draw on their own perception of the route, producing a personal map which in most cases bore very little resemblance to the actual route map.
The tests showed that although congenitally blind people do posses spatial perception, in the absence of previous visual experience they tend to "adopt egocentric or self-referent special coding strategies" (Dodds et al. 1982). These findings could be an important factor for consideration when describing layout and structure to a congenitally blind person. For a sighted person the obvious pointers and description of, for example, a route map or the plan of a building could bear little resemblance to the mental map drawn by the blind person. Could these factors also be taken into consideration when designing interfaces? Certainly the analogy of a desktop, often used to represent items in two dimensions on a PC, could be redundant to someone who has never actually seen the layout of a three-dimensional desk and has a different mental map of it.
Learning how to describe layout and surroundings is not an easy task, as each person will have their own perception of space (Dodds et al. 1982). Crossland challenges traditional rehabilitation training methods which in the past have relied on the practice of blindfolding trainee rehabilitation workers and getting them to undertake tasks or navigate around towns, as this may give them a misguided view in which they "believe that they know what it is to be blind"(Crossland 1996). Another example of this is the Channel 4 programme "Blind Man's Bluff" screened in 2001, which involved four sighted TV celebrities who were given glasses that "simulated sight loss". They were all set a task of navigating a 250 mile journey from Blackpool to London, with minimal support, the idea being to give them an idea of what it would be like to be blind.
As an alternative to this approach, Crossland stresses the importance of addressing the individual needs of visually impaired people and helping them engage in activities which are important to them, which may be "partly personal, partly cultural and partly generational". In this view, daily living skills can generally be met through advice and guidelines but need to be individually interpreted. Rehabilitation should focus on "a more client-centred approach" which helps the person "find new ways to relate to the environment and their mobility" (Crossland 1996).
The ways visually impaired people relate to the environment are discussed by Lindo and Nordholm using a model developed by Persson to compare adaptation strategies used by visually impaired people in performing activities of daily living (Lindo and Nordholm 1999). The Persson model identifies positive and negative adaptation strategies:
Positive strategies are:
· Acceptance
· Trust
· Positive avoidance
· Minimization
· Independence
· Control.
Negative strategies are:
· Denial
· Resentment
· Shame
· Isolation
· Helplessness
(Persson 1990)
Other strategies for adapting to sight loss are also discussed by Lindo and Nordholm. Comparisons are made of positive and negative adaptation strategies used by visually impaired people who attended a rehabilitation program with two other groups - one group of people with neurological problems and a group of non-disabled people. Data was collected using three models:
Persson's adaptation questionnaire (Persson 1990), which describes positive
strategies of acceptance.
The Mood Adjective Checklist (Sjoberg, Svensson 1979), which uses 71 adjectives
describing various moods, such as, "elated", "nervous",
and "indifferent", which the respondents rate on a 4-point scale.
The Activities for Daily Living (ADL) questionnaire (Kroksmark and Thoren-Jonsson
1985) which assesses the level of difficulty in performing everyday tasks experienced
by visually impaired people.
James notes that, like many other people, blind and visually impaired people are turning to the Internet for their information needs which "may be the only source that they can use to access information for their daily lives, such as bus schedules and movie listings" (James 1998 p.27). Earlier work on adapting to sight loss needs to be revisited in the context of this new environment
2.1 Everyday tasks for visually impaired people
Todd and Wolf (1994) provide a comprehensive guide to dealing with sight problems, with topics ranging from "coming to terms with sight loss" to "dealing with money matters". Everyday tasks are covered in a chapter on "Coping day by day" which describes how to make daily tasks such as cooking and housework easier by using improved lighting and colour contrasts - e.g. dark chopping board for light foods and vice versa. Not surprisingly given the date of publication, access to IT and computers is only covered briefly and some activities such as shopping may have changed since the book was written - the pros and cons of online shopping for example are not mentioned.
The RNIB produces some useful fact-sheets for visually impaired people, available via their web site (www.rnib.org.uk). These fact-sheets include how to travel independently, shopping made easier and going on holiday, as well as useful guidelines for sighted people on how to meet and interact with blind people. Advice on travelling independently includes general common sense tips such as checking bus times, making sure you are familiar with the route to a bus stop or train station, but also suggests asking if Braille timetables are available or whether there is a telephone timetable service. Advice on the use of technology for visually impaired people is also available and includes fact-sheets about personal computers, choosing the appropriate equipment, and access to the Internet.
The study by Lindo and Nordholm referred to earlier found that people expressed the most difficulty with reading, writing and watching television, followed by mobility problems such as "using public transportation, doing postal and bank errands, socializing, shopping and engaging in leisure activities" (Lindo and Nordholm 1999) and to a lesser extent daily living skills such as setting a table, eating, and drinking. The study showed that people use a combination of positive and negative adaptation strategies and that each person needs support at two levels: for coping with daily living activities and, as Crossland (1996) has also pointed out, to offer emotional support.
Kleinschmidt's study of older adults' adjustments to sight loss includes a section on the "problem solving perspective" in which a group of older visually impaired or blind adults talk about coping with everyday tasks through simple techniques such as labelling objects more clearly using "glue, toothpicks, emery boards, red blobs, and electrician's tape" (Kleinschmidt 1999) as well as listening to changing sounds such as the dial on a clothes dryer. A comment made by one person was that often it was very simple adjustments such as asking for a larger plate to avoid spilling food on the table, which made all the difference. Undoubtedly there are parallels in the use of ICTs.
2.2 Mobility issues
Travel aids have successfully improved the mobility of blind and visually impaired people by helping them to navigate their way around obstacles, often with the aid of primary aids such as a guide dog or a white stick. Development of primary aids includes obstacle detectors and sensors, laser canes and ultrasonic aids to inform people of obstacles, turnings and objects. Petrie et al. refer to this level of mobility as micro-navigation, in which people need to negotiate obstacles and pathways before moving on to the macro level of navigation which involves knowing which street they are on and in which direction they are heading (Petrie, et al. 1996). They describe the development of an electronic travel aid called the MoBIC travel aid (MoTA), which aims to address the macro-navigation problem.
The MoTA consists of two components. The first is the MoBIC Pre-Journey System (MoPS) which helps with the use of maps for planning a journey - these could include maps from public and personal sources as well as specific information such as information on specific surfaces underfoot (for example cobbled pavements and grassed areas). The second component is the MoBIC Outdoor System (MoODS), which provides orientation and navigational assistance during the journey by using the information provided in the MoPS. Types of information provided in the MoTA include landmarks such as buildings, post boxes, phone boxes etc, street names, surfaces underfoot, distance between landmarks or turns, directions and instructions for navigation.
Work undertaken by Harper on standardising electronic travel aid interaction for visually impaired people puts forward a proposal for a universal interface to aid visually impaired users (Harper 1998). The study compares real life travel tasks with virtual ones such as travelling around a website, and suggests that just as sighted people's real life travel tasks will differ from those of people with sight problems, the same is true in a virtual world. Harper thus makes the explicit connection between navigation in "real" and "virtual" environments.
The stages of a journey have been broken down into what Harper calls the "Travel Task Model", which includes elements of orientation (direction, route, desired location etc) and navigation (use of maps, landmarks, knowledge of obstacles etc). The flow of travel in the travel task model takes the following route:
· Decide on start and destination
· Pre-plan the route
· Start the journey (throughout which obstacle detection and avoidance
must be performed)
· Orient to waypoint, information point or orientation point.
· In-route guidance
· Moving to next point
· Achieve next point.
(Harper 1998 p.20).
An example of a sighted person's description of their travel task might be: "walk to pedestrian crossing and then continue to bank" whereas a visually impaired person may say "walk 20 metres ahead, then from the tactile surface walk 10 metres to the North West of that position and you are at the bank" (Harper et al. 2000). This demonstrates that in the real world it takes a sighted person much less time to orientate themselves and less time to navigate to a landmark than a visually impaired person, who needs to "break their journey into shorter stages and orientate themselves within the journey a great number of times".
2.3 Conclusions
The ways in which people adapt to visual impairment and in which navigational aids are used to overcome problems in everyday situations provide useful insights into the problems experienced in networked information environments. The literature analysed in this section illustrates how visually impaired people apply a variety of strategies to cope with daily living problems. These include reproducing materials in enhanced media such as large print, or adding features to a product such as a tactile surface or a brightly coloured label to inform the person of its contents. Parallels in a web environment would include assistive technologies to read out or magnify a screen, and accessibility features applied to the HTML encoding to enable interaction with the web page and the assistive technology. However, as in everyday life, different user needs and behaviours also need to be taken into account.
Studies of travelling and mobility reveal that someone with a visual impairment will have a very different experience to that of a sighted person. When asked to describe the travel experience they will generally reproduce a different description of the route taken - including more detailed information such as the feel of a surface or the exact number of steps taken before making a turn. Studies have also shown that someone born blind will have more difficulty with visual representation, such reproducing a map to describe a route taken. This is likely to be the same in the virtual world as the "desktop" or other layout of a computer screen or the parallel layout of a page in frames may have little meaning to someone who has never seen a web page or computer screen.
To aid travelling in the real world, navigational aids have been developed for visually impaired people such as tactile maps or route descriptions that include details of surfaces and obstacles. The way a visually impaired person "travels" around a web site will also be a different type of experience to that of a sighted person, and it is likely that these real-world experiences could be used to advise interface designers of the inclusion of useful features such as landmarks or pointers to aid navigation in the virtual world.
A clear message to emerge from the literature is that whatever the task, be it going on holiday, shopping, travelling or using a computer, people want to be able to undertake it as independently as possible and will adopt a strategy to try and attain independence and to overcome any problems. The next section will look more specifically at web design and accessibility and how these issues will impact on the ability of blind and visually impaired people to interact successfully and independently in web-based environments.
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