Learning Science · Accessibility, preferences and individual differences

Accessible representations and assistive tools

Choose representations and tools that make essential information and actions available.

Use the examples to connect this lesson with the earlier topics. No specialist equipment is needed.

After reading, you can

Provide an equivalent route to a visual relationship.
Check a tool in the actual learning task.

A diagram needs its relationship

A text alternative that says “a complicated diagram” tells a reader almost nothing about a diagram showing water moving between reservoirs. The educational information lies in the components, directions, conditions and relationships. An equivalent explanation should make those available, rather than merely naming the image.

Use complementary routes

For a graph, provide axes, units, values or relevant trends and the relationship the question asks learners to examine. A data table can support exact comparisons, while prose can explain a trend. For audio, a checked transcript supplies words; information conveyed by a demonstration may also need description.

Representations need not duplicate every visual detail. Preserve details that carry meaning and remove irrelevant decoration. An explanation of a branching process should distinguish the branches and their conditions. A label list alone loses the decision structure. W3C’s complex-image guidance recommends a short identifier together with a fuller description of essential information.

An invented specimen key, not a biological taxonomy. It supplies decision structure without supplying any specimen’s observed features.
First feature: band?	Second feature: spot?	Destination in invented key
Yes	Yes	Group A
Yes	No	Group B
No	Yes	Group C
No	No	Group D

Tools and content must work together

Assistive tools may include screen readers, magnification, alternative input or speech recognition. Their usefulness depends partly on how the material is structured. A screen reader cannot reliably infer unlabeled controls, a missing reading order or a mathematical relationship embedded in an unexplained picture.

Test the actual task, including interaction and response. Can the learner navigate to the needed value, compare it with another and submit an answer? Invite the user’s feedback; a compliance check and a real learning task provide different evidence. Keep a workable alternative when an interaction cannot yet be made accessible.

Worked example

Describing a branching classification

What must the text preserve from the branching classification key?

A biology exercise asks learners to identify a specimen using two binary decisions. The accessible text states the first feature, each possible answer and the next decision reached. It preserves the same evidence and decision order as the diagram. Learners can navigate the text or the diagram, then justify their identification from the observed features. The description does not reveal which specimen is correct; it supplies the structure needed to reason.
The classification text should be checked for navigation as well as wording. A learner needs to know which decision follows each answer without holding the entire tree in memory. Headings, clear links or a structured outline can preserve this relationship. The accessible route should support returning to a previous decision, just as a sighted reader can revisit a diagram branch.

Preserve each feature question, yes/no condition and destination, with a way to revisit branches. A label list loses the decision structure.

An invented key with four complete paths

Ask band present. If yes, ask spot present: yes leads to A, no to B. If no band, ask spot present: yes leads to C, no to D. Codes are invented groups, not biological species. No specimen observations are supplied.

Try it yourself

Think through each question before opening the answer.

Why is “image of a graph” insufficient alternative text?
Show the answer and reasoning
It identifies a format but omits the values, relationships and conditions that carry the learning information.
The learner still needs axes, values or branch conditions to answer the question carried by the image.
Does a transcript always replace a practical demonstration?
Show the answer and reasoning
No.
It supplies spoken content, but movement, spatial relationships or other visual information may also require an appropriate description or alternative activity.

What to carry forward

Make essential relationships available in each usable route.
Check tools with the actual navigation, reasoning and response task.

References

Sources supporting the explanations and learning checks in this lesson.