Dual coding theory
Dual coding theory says that information presented in two complementary forms, such as words and pictures, is remembered better than information presented in one form alone.
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- Cross-curricular
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Allan Paivio proposed in the 1970s that the mind has two related but separate channels for processing information, one for verbal material and one for visual material. Richard Mayer turned the theory into a practical instructional framework over the next two decades.
What it is
Two channels in working memory: a verbal channel for spoken and written language, and a visual channel for images, diagrams, and spatial layout. When learners process the same information through both channels, they build two interconnected mental representations rather than one. Each acts as a retrieval cue for the other.
Why it works
A second channel reduces extraneous load on the first. A diagram next to a definition lets pupils hold less of the explanation in their head and free up capacity for the actual thinking.
Mayer’s multimedia principle says people learn more from words and pictures than from words alone. He has run dozens of controlled experiments across age groups and subjects, with consistent effect sizes. The EEF cognitive science review treats dual coding as well evidenced.
How to use it
Pair definitions with icons or small images. Show timelines for sequences, maps for places, flowcharts for processes. Put labels next to the part of the diagram they refer to, not in a key at the bottom. Use the same visual to anchor a concept across multiple lessons so the visual becomes a retrieval cue.
Avoid mixing words and pictures that compete for attention or repeat each other without adding meaning.
When not to use it
If the visual carries no meaning, it is decoration and adds to extraneous load. Stock photos and clip art used to liven up a slide usually do harm, not good.
Related Chalk tools
Visual Keywords, Icon Storyboard, Frayer Model, and Graphic Organiser are built on the dual coding principle.
Evidence
Allan Paivio's two-channel theory of mental representation is supported by decades of lab research and has been translated into Richard Mayer's multimedia learning principles, which rest on dozens of controlled experiments across age groups and subjects.
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Related concepts
Questions teachers ask
Is dual coding just adding pictures to slides?
Does it mean I should avoid text-only resources?
How is this different from learning styles?
Visual Keywords
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