When it comes to mobile usage, the context in which the application or device is used will impact drastically on the user experience. To cover this explicitly, the concept of “situation induced disabilities” or “Situational Impairments” has been introduced. Recognizing that non-optimal usage situations cause situation induced disabilities, and that this is something which happens to everyone has important advantages:
- Accessibility no longer becomes a question of “us and them” implicitly favoring an inclusive approach.
- Focusing in users in general is motivating for designers and developers without particular interest in accessibility.
Both designers and developers typically work in an office environment, meaning that the situations they encounter, and the contexts in which they work, are often very different from the actual mobile usage situations and contexts. In addition there is a tendency to focus on the abilities of a person as something stable by talking of target user groups, personas etc. This obscures the inherently dynamic nature of mobile usage, where non-optimal conditions often occur:
- Non-optimal lighting (e.g. bright sunlight), or the user has or wants to look elsewhere (while crossing a street, negotiating rough terrain, etc.).
- Noisy environment (e.g. in a crowd, by a busy street, at train station, at festival or fair, etc) or an environment where sounds are not suitable (e.g. meeting, concert, theater, bird-spotting – not to frighten the birds etc.).
- Situation which limits your ability to touch the device - cold hands, using gloves (cold weather or keeping the device in a pocket or a bag) or external vibrations/shaking makes it hard to sense the feedback.
- Situation which limits your ability to manipulate the device like having to hold something else in one or both hands (e.g. umbrella, bag, take away coffee, ice cream, pram, child, etc.) or shaking/vibrations that make it difficult to interact.
- Context that requires attention (e.g. other people, traffic, sights, scenery etc.).
Such non-optimal conditions make the user “effectively” impaired (situation induced impairment). In order to put more accessible design higher on the agenda, we suggest that it is important to explicitly make a range of different usage situations available to the design-team. Such scenarios (i.e. key scenarios) should be documented both with pictures (similar to those in Figure 2) and short video clips giving a richer perspective of the context-dependency and dynamics of mobile usage.
We argue that the mobile situation is inherently dynamic, but we often fail to recognize how quickly the users switch between different situations and contexts, and to be able to consider not only the use case of “sitting at a desk” or “making a phone call”, one needs to define a range of scenarios covering noisy environments, bright sunlight, moving around, one-handed usage, situations where the environment needs a lot of attention (e.g. crossing a street), etc.
Figure 2. Mobile usage
See also Dynamic User Experiences.