Dual coding is a theory of cognition introduced by Allan Pavio in late 1960s. This theory suggests two distinct subsystems contributing to cognition: one is specialized for language and verbal information, and the other for images and non-verbal information.

• “The most general assumption in dual coding theory is that there are two classes of phenomena handled cognitively by separate subsystems, one specialized for the representation and processing of information concerning nonverbal objects and events, the other specialized for dealing with language.”¹⁾

Paivio, Allan. Imagery and verbal processes. Holt, Rinehart and Winston. New York, 1971.