To be effective in diverse classrooms, curricula must present information in ways that are perceptible to all students. It is impossible to learn information that is imperceptible to the learner, and difficult when information is presented in formats that require extraordinary effort or assistance. To reduce barriers to learning, therefore, it is important to ensure that key information is equally perceptible to all students by: 1) providing the same information through different sensory modalities (e.g. through vision, or hearing, or touch); 2) providing information in a format that will allow for adjustability by the user (e.g. text that can be enlarged, sounds that can be amplified). Such multiple representations not only ensure that information is accessible to students with particular sensory and perceptual disabilities, but also easier to access for many others. When the same information, for example, is presented in both speech and text, the complementary representations enhance comprehensibility for most students.
1.1 Options that customize the display of information
In print materials, the display of information is fixed, permanent, one size fits all. In properly prepared digital materials, the display of the same information is very malleable; it can easily be changed or transformed into a different display, providing great opportunities for customizability. For example, a call-out box of background information may be displayed in a different location, or enlarged, or emphasized by use of color, or deleted entirely. Such malleability provides many options for increasing the perceptual clarity and salience of information for a wide range of students and adjustments for preferences of others. While these customizations are difficult with print materials, they are commonly available automatically in digital materials.
Information should be displayed in a flexible format so that the following perceptual features can be varied:
- the size of text or images
- the amplitude of speech or sound
- the contrast between background and text or image
- the color used for information or emphasis
- the speed or timing of video, animation, sound, simulations, etc
- the layout of visual or other elements
1.2 Options that provide alternatives for auditory information
Sound is a particularly effective way to convey the impact or “energetics” of information, which is why sound design is so important in movies and why the human voice is particularly effective for conveying emotion and significance. However, information conveyed solely through sound is not equally accessible to all students and is especially inaccessible for students with hearing disabilities, for students who need more time to process information, or for students who have memory difficulties. To ensure that all students have equivalent access to learning, options should be available for any information, including emphasis, presented aurally.
- Text equivalents in the form of captions or automated speech-to-text (voice recognition) for spoken language
- Visual analogues for emphasis and prosody (e.g. emoticons or symbols)
- Visual equivalents for sound effects or alerts
1.3 Options that provide alternatives for visual information
Graphics, Animations, or Video are often the optimal way to present information, especially when the information is about the relationships between objects, actions, numbers, or events. But such visual representations are not equally accessible to all students, especially students with visual disabilities or those who are not familiar with the graphical conventions employed. To ensure that all students have equal access to that information, provide non-visual alternatives that use other modalities: text, touch, or audition.
- Descriptions (text or spoken) for all graphics, video or animations
- Touch equivalents (tactile graphics) for key visuals
- Physical objects and spatial models to convey perspective or interaction
Text is a special case of visual information. Since text is a visual representation of spoken language, the transformation from text back into speech is among the most easily accomplished methods for increasing accessibility. The advantage of text over speech is its permanence, but providing text that is easily transformable into speech accomplishes that permanence without sacrificing the advantages of speech. Digital synthetic text to speech is increasingly effective but still disappoints in the ability to carry the valuable information in prosody.
- Properly formatted digital text (e.g. NIMAS, DAISY). Such text can be automatically transformed into other modalities (e.g. into speech by using speech by text-to-speech software or into touch by using refreshable Braille devices) and navigated efficiently by ScreenReaders
- A competent aide, partner, or “intervener” who can read text aloud as needed