The National Center on Accessibility, now a part of the Eppley Institute, provides a wide range of accessibility-based services including training, consulting, advising, and technical assistance. One of the services, is the testing of prototypes with people with many different types of disabilities. This briefing, however, focus is on people who are blind or have vision impairments for this article.
Three-dimensional models, such as replicas, scale models, and tactile maps, are very effective tools for communicating interpretive information. When visitors are able to touch and explore 3-D models, they can be even more meaningful—especially for visitors who are low vision. But how do you know if a model is communicating the information you want it to convey? The simple answer is, you test it.
Since tactile models are expensive to produce, they typically remain in place for as long as 10 to 20 years. So, it makes sense to be as certain as possible about the size, design, and components of a model before, literally, casting it in bronze. Testing prototypes of tactile models with people who are blind or have vision impairments is one of the services the National Center on Accessibility (NCA) has been providing for its clients. And, these projects have created some lessons learned for NCA that are emerging around tactile models.
First, to engage the disability community, NCA aims to include people with different types and levels of vision loss (low vision to no functional vision) as well as individuals who have been impaired since birth and those who lost their sight as children or adults as reviewers. The extent of vision loss affects whether the reviewer is primarily receiving information about the model strictly by touch or a combination of vision and touch. The timing of vision loss affects the extent to which the individual has visual memory of colors, objects, people, and places. Other issues that need to be considered include whether an individual reads Braille or raised lettering and the extent of their experience with tactile graphics and models. All of these can impact how easily a reviewer is able to distinguish and understand different aspects of a model.
If possible, NCA recruits reviewers from a project’s “home” community because they are more likely to be familiar with the project’s site and subject matter. This means the reviewers may more easily place the model being tested within a larger context and the broader interpretive messages the site is hoping to share. Local recruitment also provides an opportunity for the site to build relationships with people and organizations that represent the disability community. Through the review process, both entities learn about and from each other, and these relationships can be built upon to provide improved or more expansive programs and services.
Secondly, the tactile model review process itself needs to include exploration of the following, based on the individual’s abilities and experience:
- Reach around and “into” the model:
- Is the reviewer able to reach all critical areas of the tactile element with finger tips?
- Overall feel:
- Is the model comfortable to touch? Are there any sharp spots or textures that are irritating or annoying?
- Are the textures and elements detailed enough to discern important components?
- If more than one texture is used to delineate spaces, objects, or concepts, are they easily distinguishable?
- If dots, dashes, or other textures or forms are used for different lines (trails, routes, roads, etc.), are they easily distinguishable?
- Braille (Braille readers only):
- Is it discernable and comfortable to the touch?
- Is it correct? (This should be confirmed by a professional.)
- Does it appear to have the correct size and spacing? (This should be confirmed by a professional.)
- Raised lettering meant to be tactilely read
(Raised lettering readers only):
- Is it discernable, readable, and comfortable to the touch?
- Effectiveness as an interpretive element:
- Does the model aid in understanding the purpose and message of the wayside or exhibit?
Is it fun and relatively easy to explore and understand or does the user have to “work” at it? A non-sighted user should not have to exert considerably more physical or mental effort than a sighted user does to understand the model and the interpretive message it is meant to convey.