Dual coding for studying: When a diagram actually helps
Learn when words and diagrams work better together, when visuals become a distraction, and how to study both parts without turning your notes into an art project.
A page on kidney filtration might contain a paragraph explaining what each part of a nephron does and a diagram showing where those parts sit along the route. The diagram earns its place because location, order, and direction are part of the idea. A stock photo of a kidney beside the same paragraph does not teach those relationships.
That difference matters more than whether a set of notes looks visual. Words and pictures can work well together when each one carries information the other cannot communicate as clearly. Adding an image simply because the page contains a blank space is decoration, not a study method.
What dual coding means for a student
Dual-coding theory proposes interconnected verbal and nonverbal systems for representing information. A related but distinct body of multimedia-learning research asks a practical question: When does an explanation work better with words and a relevant graphic than with words alone? (Clark and Paivio, 1991)
Across 29 reviews of multimedia design, several choices produced average learning benefits, including placing related words and graphics near each other and removing irrelevant details. The effects depended on how the lesson was designed and were more important with complex material. This evidence supports deliberate combinations of words and graphics, not adding a picture to every paragraph. (Noetel and colleagues, 2022)
This also has nothing to do with diagnosing someone as a visual learner. A diagram may suit a topic because the topic contains a spatial, structural, or quantitative relationship. That choice should come from the material and the task, not a learning-style label. The learning styles guide explains that distinction in more detail.
Give the visual a specific job
Before making a diagram, decide what it must show. A useful visual usually makes one of these relationships easier to inspect:
- Location or structure: where parts sit and how they connect, as in anatomy, molecular structure, or a circuit.
- Sequence or movement: what happens first, what follows, and where something travels through a system.
- Cause and effect: how a change in one part affects another part of a process or feedback loop.
- Quantity: how values compare or change, as in a graph, table, or number line.
- Hierarchy or comparison: which ideas belong together, differ from one another, or sit above and below one another.
A diagram is worthwhile when that relationship is part of what the course expects a student to understand. A timeline can clarify the order of events, but it cannot replace the evidence behind a historical argument. A graph can show the direction and size of a change, but it still needs words that explain what the axes represent and why the pattern matters.
A 2025 narrative review of learning by drawing reaches a similarly conditional conclusion. It reports positive, mixed, and negative or null findings, with results varying by the task, the kind of visual, study time, test alignment, spatial ability, and drawing skill. “Draw this” is not a complete study instruction. (Dechamps and Skulmowski, 2025)
When a picture adds little
Some visuals are connected to the topic without explaining it. A photograph of a laboratory does not clarify the steps in a reaction. A decorative brain icon does not explain how two brain regions interact. Color around a definition does not create another representation of the definition.
Research calls interesting but instructionally irrelevant additions “seductive details.” A 2026 multilevel meta-analysis found a small negative effect on learning outcomes on average, with considerable variation across studies. The useful lesson is narrower than “pictures are distracting”: every element should help the reader perform the learning task. (Cheng and colleagues, 2026)
A visual also becomes unhelpful when it is inaccurate, too crowded to follow, or disconnected from the explanation. An elegant diagram with a missing step is still a bad source. When the course provides an official figure, graph, model, or map, begin there rather than relying on a simplified version found elsewhere.
More is not automatically better. In multimedia lessons, duplicating spoken narration as identical on-screen text can create a redundancy cost under some conditions, while brief labels beside relevant parts can help connect a static diagram to its explanation. For a study diagram, keep the words that identify or explain the visual relationship rather than copying the surrounding paragraph into the graphic. (Noetel and colleagues, 2022)
Use the diagram instead of admiring it
Looking at a finished visual can make a process feel obvious because the labels, arrows, and layout are supplying cues. To find out what can be produced without those cues, remove the source and try to reconstruct the relationship from memory.
Use this sequence with one course visual:
- Identify the job. Write the relationship the visual must explain: the route through a system, the variables in a graph, the stages in a process, or the connection between parts.
- Explain it with the source open. Point to each important part and state what it contributes. If an arrow changes direction, explain why. If a graph changes slope, say what that change means.
- Remove the source. Rebuild the essential visual or sketch its structure from memory. Artistic quality does not matter; the required parts and relationships do.
- Check the result. Compare the attempt with the assigned source. Correct wrong labels, missing links, reversed directions, and unsupported explanations.
- Test it again later. Recreate the visual and explain it without looking. A correct drawing without an explanation may hide shallow understanding, while a fluent explanation may hide a missing spatial relationship.
The closed-source attempt adds retrieval practice to the visual task. Reviews of classroom research have found benefits from retrieving information across many subjects and education levels, but that evidence supports the general act of retrieval rather than a special claim about redrawing diagrams. (Agarwal, Nunes, and Blunt, 2021)
A worked example from economics
Consider a supply-and-demand graph for a binding price ceiling. The picture has a clear job: it shows the controlled price below equilibrium and the distance between quantity supplied and quantity demanded at that price.
Start with the graph assigned in the course. Read the axes, identify both curves, find the equilibrium, and locate the price ceiling. Then explain the relationship in words: at the controlled price, buyers demand more of the product than sellers supply, creating a shortage equal to the horizontal difference between those quantities.
Next, close the source and reconstruct only what matters. Draw and label the axes, curves, equilibrium, ceiling, quantities, and shortage. Explain each mark while adding it. When the source is reopened, a curve drawn in the wrong direction signals a different problem from a missing explanation of why the shortage occurs. The correction should target that specific gap.
The same routine works with a biological pathway, a chemical structure, a circuit, or a historical timeline, but the visual must match the course task. If an economics exam requires a written policy evaluation, the graph is one part of the answer rather than the entire answer.
Build the verbal layer in Bananote
Bananote can keep the explanation and practice questions tied to the course material while the original figure remains the authority for visual details.
Start with the source that contains the verbal explanation: a course PDF, pasted text, live or uploaded audio, a YouTube lecture, an existing note, or a printed textbook page captured with Scan Text on iPhone or iPad. Review the resulting note against the original before building study material from it, especially for symbols, measurements, technical vocabulary, and causal steps.
Then use one verified note to support the visual study routine:
- List the relationships the course visual represents.
- Turn those relationships into flashcards or quiz questions.
- Keep the original visual nearby when checking labels, shapes, directions, and values.
- Ask AI chat about relationships that are actually described in the note, then verify its response against the note and original source.
- Recreate the visual separately and explain it aloud or in writing.
A bounded chat prompt keeps the task useful:
> Use only this note to ask me one question at a time about the relationships among the parts of this process. Wait for my answer, then quote the passage that supports your feedback. Mark anything the note does not establish instead of supplying a missing label, value, or visual detail.
This division of labor is deliberate. Bananote organizes the words and creates practice from a verified note. The student still reads the official visual, decides what it represents, checks the details, and produces the explanation.
Frequently asked questions
What is dual coding in learning?
Dual-coding theory proposes verbal and nonverbal systems for representing information. In practical studying, the idea is most useful when words explain a concept and a relevant visual shows a relationship such as structure, sequence, movement, or quantity.
Is dual coding the same as being a visual learner?
No. Learning-style labels claim that instruction should match a person's preferred mode. Choosing a diagram because the subject contains a spatial relationship is a decision about the material, not a diagnosis of the learner.
Should every set of notes include diagrams?
No. Use a visual when it communicates information needed for the course task. Decorative images, crowded layouts, and pictures that merely repeat the topic can add work without improving the explanation.
Is copying a diagram useful?
Copying can help someone become familiar with a visual or produce a clean reference, but it does not show what can be reconstructed without the source. Follow it with a closed-source attempt, an explanation of the relationships, and a check against the assigned material.
How does Bananote fit in?
Bananote can turn supported course sources into structured notes, flashcards, quizzes, and single-note chat practice. Use the original course visual to verify graphical details, and use Bananote for the verbal explanation and questions tied to the verified note.
A useful diagram carries part of the course content. Give it one clear job, connect it to an accurate explanation, and test whether both the visual relationship and the reasoning can be produced without the source.
Try Bananote with one course source, verify the note, list the course-relevant relationships from one visual, and turn that checked list into questions for the next study session.
Sources
- Clark and Paivio: Dual Coding Theory and Education
- Noetel and colleagues: Multimedia Design for Learning—an overview of reviews with meta-meta-analysis
- Dechamps and Skulmowski: The effective design of tasks involving learning by drawing
- Cheng and colleagues: Seductive details, cognitive load, and learning outcomes
- Agarwal, Nunes, and Blunt: Retrieval practice consistently benefits student learning