On this page
Look at a good NCERT page on the heart and you will see words and a diagram doing different jobs. The text says what happens; the diagram shows where. Dual coding is the idea that learning both, and linking them, gives you two ways back to the same memory.
What does dual coding mean?
Dual coding theory was first proposed by the psychologist Allan Paivio in the late 1960s. It holds that the mind processes information along two channels, verbal and nonverbal, which can work separately or together. Paivio reviewed the theory's evidence in a 1991 paper.
For a student, the practical version is simple: when an idea has a shape, a layout or a sequence, put it down in words and as a picture, and connect the two.
What does the research support?
Simple diagrams beside text help understanding. Butcher had students learn about the heart and circulatory system from text alone, text with simplified diagrams, or text with detailed diagrams. Both kinds of diagram helped students build a working mental model, generate inferences and make fewer comprehension errors. The simplified diagrams did best for factual learning and for pulling information together. A clean sketch can beat a detailed copy.
Drawing helps memory. Across seven experiments, Wammes, Meade and Fernandes found that drawing words led to better recall than writing them, and the effect held up when study time was shorter and lists longer. These were word lists, not textbook chapters, so treat it as evidence that drawing is worth the time, not as a full study method.
Drawing plus explaining helps most. In a study by Fiorella and Kuhlmann, described in Logan Fiorella's 2023 chapter on learning by teaching, college students learned about the respiratory system and then recorded a lesson. One week later, those who explained aloud while drawing outperformed those who only explained or only drew. Their explanations were also more elaborate.
What doesn't it mean?
It doesn't mean finding out whether you are a "visual learner". Pashler and colleagues' review of learning styles set out what evidence would be needed to show that teaching should match a student's preferred style, and our post on the learning styles myth covers why that idea hasn't held up.
It also doesn't mean decorating notes. Dunlosky's *American Educator* summary of study techniques rated imagery for text as limited to imagery-friendly material, with benefits that can be short-lived. A drawing has to carry meaning: a structure, a direction, a sequence or a relationship.
A note page template to copy
Split each page into two halves.
Left: words. Short statements in your own words, numbered.
Right: picture. A simple diagram with only the parts the words mention. Label it with the same numbers.
Example for double circulation (Class 11 biology):
Right ventricle pumps deoxygenated blood to the lungs.
Oxygenated blood returns to the left atrium.
Left ventricle pumps it to the body.
Deoxygenated blood returns to the right atrium.
On the right, draw four boxes for the chambers, a loop to "lungs" and a loop to "body", with arrows numbered 1 to 4.
Example for physics: beside "net force along the incline is mg sin θ minus friction", draw the free-body diagram with each force labelled. Our post on drawing the diagram first shows why this pays off in problems.
The review routine
Cover the right half. Redraw the diagram from your words.
Cover the left half. Explain the diagram aloud, number by number.
Compare with the textbook figure and fix errors in a different colour.
Some ideas, such as wave interference or field lines, are hard to capture in one static sketch. The Fermi Simulation Lab has interactive simulations for ideas that are easier to see than to read; watch one, then draw what you saw from memory.
Rewrite one chapter's notes in this two-column format this week, and use the review routine twice before your next test.
