The instructional success of a diagram is only partly due to its design. Even poorly designed diagrams can be made instructionally more effective by embedding them in a suitable context.

How making existing diagrams more successful as aids to instruction?
How helping learners process diagrams more effectively?
- Changing learners' attitudes to diagrams: treating diagrams differently from the way treating everyday pictures.
- Providing learners with strategies to construct an appropriate meaning from the diagram.
- Supporting particular diagrams with additional resources.

Increasing learner involvement

How preventing the learner from ignoring the diagram:
- Use inescapable connections which produce a strong integration between diagrams and their companion modes of presentation.
- Be more prescriptive in the way you expect learners to treat the diagrams.
- Prefer giving too much support rather than too little.

Most instructors are used to thinking of diagrams as a solution to instructional problems - rather than having the potential to be problems in themselves.

Encourage activities involving various types of mental manipulation of a diagram's constituents:
- Adding markings to a diagram.
- Annotating particular regions of the diagram.
- Labelling the diagram from memory.
- Modifying the diagram so that some of its components are changed.
- Redrawing the diagram.
- Drawing completely new diagrams.

Guide the learner thru the types of mental processes that will help them to fulfil the diagram's potential as an instructional tool.

Long-term goal: helping learners become independently capable of dealing with diagrams in general in a systematic and instructionally productive manner.

Give learners explicit guidance in the form of a checklist of questions they can ask themselves working with the diagram:
- Have I had a good look at everything in the diagram? Am I being systematic, analytical and thorough?
- What do I already know that may help me work out what's going on here? Have I come across something like this before?
- Which are the main pieces that make up this diagram? How do I break it up into chunks?
- How does each of the main chunks of the diagram give me clues about the other chunks? Can I find the relations that must exist within the diagram?
- What special diagram techniques have been used to depict the subject matter? What would it be like if I could see the real thing?

The challenge goes beyond designing better diagrams:
- developing learners' visual literacy with respect to diagrams,
- building diagram-processing knowledge and skills.

Deeper diagram processing

Reasons why the content of everyday pictures is easier to process:
- relative familiarity of the subject matter,
- lack of importance of most of the material in the picture,
- essentially literal representation of the subject matter.

However, diagrams are an extremely concentrated and artificial form of representation.
In a diagram, everything needs to be treated as potentially important.
Each entity and spatial relation has its own special significance within the diagram, and learners need to appreciate these significances.
Diagrams need to be deeply processed in order that they perform their intended instructional function properly and completely:
- going beyond the superficial graphic characteristics of the diagram,
- comprehensively interpreting what those characteristics are intended to mean in terms of the subject matter that the diagram depicts.

Manipulations for deeper processing
Types of mental manipulations:

Justifying the graphic treatment of an entity within the diagram, or rendering used on an entity
Visual cues signal to the viewer how the material it contains should be interpreted: different types of shading.

Classifying the entities used in the diagram
- visible and invisible parts of the subject matter
- interpretation aids
- graphic instructions (boxes, arrows)
- coding devices (shading)

Tasks of classifying diagram components into these categories
- help examining all entities in the diagram,
- prepare the learners to treat these functionally distinct entities differently in the interpretation of the diagram.

Comparing different representations of the same subject matter
Comparing realistic and diagrammatic representations, between different views, different purposes:
- Connecting corresponding entities in the two diagrams.
- Marking corresponding entities in depictions showing similar but not exactly the same subject matter.

Comparing different parts of the same diagram
- Considering all the entities in the diagram.
- Making the internal relations more explicit.
- Putting into words the difference between different types of graphic signals.
- Spelling out the relations between some of the entities in the diagram.

Making modifications to existing diagrams
- Mentally changing the structure of a system: for performing different functions.
- Leaving the structure alone but changing the state of the system.

Linking the material in the diagram to existing background knowledge
- Activating the background knowledge of the learners. - Comparing with related but different subject matter from the own experience and building up external relations.

Transforming aspects of the diagram into another representational form
- Finding a different way to express the diagram's graphic entities and relations: analysing the existing diagrammatic representation, articulating its essential aspects, set up a text-based explanation of the process.

Imagery

Visual comprehension and memory is part of what is required to develop a proper understanding of the subject matter and be able to recall it effectively. Our minds store some information in the form of images and some information in a far more abstract propositional form (facts and their relations). These two memory stores are linked.

Encouraging learners to develop well-formed mental images from a diagram: