Dual Coding

What is dual coding?

Dual coding is a cognitive theory and a learning strategy built on it. It goes back to the Canadian psychologist Allan Paivio, who developed it from the late 1960s onward. The theory holds that people process information in two separate but connected systems: a verbal system for language and words, and a nonverbal or imagery system for pictures and sensory impressions.

How does dual coding work?

When content is processed through both systems – for example a concept together with a fitting picture or diagram – two separate but linked memory traces are formed. Paivio called these links "associative connections." Because the information can then be retrieved through two routes, the chance of recalling it later increases. Concrete terms are easier to picture than abstract ones; for abstract content, symbols, metaphors, or schematic diagrams can help. As a learning strategy, dual coding therefore means deliberately pairing text with visuals such as sketches, diagrams, timelines, or symbols.

What is supported – and what is not?

The basic idea of two processing systems is well supported and aligns with research on multimedia learning. Paivio originally developed the theory to explain why concrete, imageable words are usually remembered better than abstract ones. An important distinction, though: dual coding means linking word and image, not the popular but empirically unsupported idea of fixed "learning styles" (such as "visual" versus "auditory" learners). The benefit comes from combining both channels, not from matching a supposed single type.

What should you watch out for?

Image and text should complement the same content rather than present the same information twice in competing ways, which can burden working memory. Effective dual coding uses images that carry the explanation and places them close to the related text in space and time. It also overlaps with Richard Mayer's principles of multimedia learning, which stress that well-aligned word–image combinations aid understanding more than text alone. Used well, the method supports understanding and retention without extra effort for the learner.