The science of learning with text and images together — and how to actually apply it
Last updated March 2026
Dual coding theory, proposed by cognitive psychologist Allan Paivio in 1971, states that the brain processes and stores verbal information and visual information in two separate but interconnected systems. When you encode something in both systems — seeing a diagram while reading the explanation — you create twice as many retrieval pathways, making recall significantly easier and more reliable.
You'll often see "dual coding improves retention by 65%" cited online. Let's address this directly: the 65% figure comes from a specific study comparing text-only vs. text-plus-illustration learning for instructional material. It's not a universal number that applies to all contexts, but the underlying finding is robust.
Sources: Paivio (1986); Mayer & Gallini (1990); Mayer (2009) Multimedia Learning.
The bottom line: the principle is real and well-supported. Combining verbal and visual encoding genuinely improves retention. The specific 65% figure is a reasonable approximation for informational content with high-quality visuals.
Paivio proposed that we have two distinct cognitive systems for storing information:
Processes language — words, descriptions, definitions, sequences. Stores information as linguistic units ("logogens").
Activated by: reading, listening, written notes, verbal explanations
Processes non-verbal information — pictures, spatial relationships, diagrams, mental images. Stores information as mental images ("imagens").
Activated by: diagrams, charts, illustrations, mental imagery, spatial layouts
Critically, these two systems are interconnected. When you see a diagram of the heart and simultaneously read the explanation, both systems encode the information — and they create links between each other. Later, reading the word "mitral valve" can trigger a mental image of the anatomy, which aids recall. The visual pathway provides a second retrieval route to the same information.
Draw the diagram of a process (e.g., cell division, the Krebs cycle) and add your own text labels that explain each step. The act of constructing both the visual and verbal components simultaneously is more powerful than viewing someone else's annotated diagram.
Best for: biology, chemistry, anatomy, engineering systems
Create a visual map of how concepts connect, then write a brief verbal summary of each connection. The spatial layout (visual) plus the explanation (verbal) creates dual encoding for both the concepts and their relationships.
Best for: history, social sciences, medical pathophysiology
Draw a timeline with key dates marked visually, then write brief annotations for each event. The visual sequence aids temporal recall; the verbal annotations add detail.
Best for: history, chronological processes, project planning
Combine verbal mnemonics with vivid mental images. To remember that dopamine is involved in reward: pair the word "dopamine" with an image of someone dopamine-happy (jumping with joy). The verbal label and the visual image reinforce each other.
Best for: pharmacology, medical terminology, foreign vocabulary
When solving problems (physics, maths, engineering), draw a diagram of the system alongside the written steps. Students who sketch problems solve them more accurately and remember the method longer.
Best for: physics, engineering, maths, chemistry
Create flashcards where one side has an image (anatomy diagram, chemical structure, historical map) and the other has the verbal explanation. This forces you to connect visual and verbal representations during retrieval.
Best for: anatomy, geography, pharmacology, organic chemistry
Take notes that mix text with quick sketches, icons, and spatial layouts. You don't need to be artistic — even rough diagrams that represent relationships spatially activate the imagery system.
Best for: any subject where you attend lectures or watch videos
Dual coding theory is sometimes confused with learning styles ("I'm a visual learner"). These are different things. Learning styles theory — the idea that people learn best when taught in their preferred modality (visual, auditory, kinaesthetic) — is not supported by evidence. Extensive research has failed to show that matching teaching style to learning preference improves outcomes.
Dual coding is different: it says that everyone benefits from combining verbal and visual representations, because the two encoding systems are universal features of human cognition, not individual preferences. You don't have to be a "visual learner" to benefit from diagrams — you're human, and you have both systems.
StudyCards AI generates flashcards from your notes and supports image cards — so you can build dual-coded decks without manual effort. Export to Anki for optimal spaced repetition.
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