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An Insight into Designing for Disabilities
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Consistency within an application is also important in the formation of mental models. Depending on the user's disability and experiences, they might not have a fully developed mental model of how an application is expected to function. Any unsuspected changes in consistency within an application can cause the development of the user's mental model to slow down. This break in consistency makes it harder for the user to predict where an item may appear. This can lead to frustration, causing the user's confidence level to drop and as a result begin questioning their every action with the system. By displaying items consistently, it maximizes efficiency, increases learnability, and helps the user better predict their actions.
The way the information is received from the source and displayed on the page is very important. If the information is received in a format that is not accessible then it is hard if not impossible to make it accessible. Information that uses acronyms may be very hard for screen readers to interpret. In most cases instead of reading the acronym the screen reader will interpret the acronym as a word and try to make sense of it. The amount of information that is given to the user is also important. An over abundance of information can be hard on the elderly or learning disabled who have attention problems or learning problems. It's important that the amount of information be kept to a minimum and is written in a non-technical straight-forward way. Simeon Keates from the University of Cambridge, states, "The design of the interface for maximum user understanding and minimum cognitive load is an essential component of the successful development of a truly usable and accessible product."
Once the information has been received in an accessible format it must then be displayed in a format that is accessible to all users. For example, when buying tickets to a concert, a map of the stadium is usually shown with the seating selection highlighted within the map. Although this makes sense to users with good sight its vital that we think of how this information might be interpreted by a blind user. A better way to display this information might be by using sound.
A tone could be generated from a central area, which would be the stage and as the user moved the mouse over the different sections of the theater a tone would be sounded that could be compared to the existing tone emulating from the stage. For instance, when moving the mouse over the rear left section of an auditorium a tone would be generated from the left speaker at a much lower volume than the constant tone coming from the center of the stereo sound. This would help the blind user understand that their seating is in the back left section of the auditorium. This would also allow the same visual design to be given to both the visually disabled and person with perfect eye-sight. Both groups of people would share the same user experience with a different but specific solution adapted for each.
Using sound for voice assistance can be an important tool for the elderly. Voice assistance can help users build mental models or even learn to use an application without the existence of a mental model. The people at the Speech Project at Oxford Brookes University developed a web browser for the visually impaired that utilized a system called "voice help". The assistance of "voice help" provided the user with spoken word as to where they were in the application and what actions they could perform at any given point. Through the testing of this application they found that older adults who used "voice help" were able to successfully use the web where they had been unable to before. They also discovered that "Each user's personal confidence increased markedly following a particularly successful interaction, and decreased following a disaster." For an elderly user this type of voice assistance helps keep their attention on the application, allows for them to understand where they are in a process and better helps them predict what might be the outcome of their actions. If the user becomes frustrated and the application makes them feel less confident in their abilities the chances of them using this application again or on a regular basis are slim.