Dual Coding Theory

Dual coding theory (DCT) is a general theory of cognition that was first introduced by Allan Paivio in the 1970s as part of the cognitive revolution in psychology. It has since grown and expanded to explain issues such as various forms of literacy, intelligence, expertise, creativity, and the evolution of the human mind. Its relevance to educational technology is fundamental—it serves as a basis of virtually all current theories of multimedia learning. This entry explains DCT in general terms and discusses its relevance to educational technology, particularly multimedia learning.

The central assumptions of DCT can be stated succinctly. DCT assumes that all cognition involves the activity of two qualitatively different mental codes: a verbal code specialized for dealing with language, and a nonverbal code specialized for dealing with knowledge of the world in the form of mental images. These two codes form separate complex systems that can operate independently, in parallel, or through an array of interconnections. The qualitative differences between the two codes account for the flexibility found in human cognition. The verbal code dominates in the performance of some tasks, and the nonverbal code dominates in the performance of other tasks, but in everyday life, the two systems are often used interconnectedly. A key principle of DCT is that memory can be enhanced when information is stored in both codes (i.e., dual coding) because the effect of the codes is additive.

DCT is based on the common assumption in psychology of continuity between perception and memory. External experiences occur through the stimulation of our five sensory modalities and are neurologically stored in memories that retain some of their original, sensory qualities. Therefore, the verbal code is developed as we hear and remember spoken language, see and remember written or signed language, and even feel and remember the touch of Braille.

Likewise, the nonverbal code develops as we hear and remember nonverbal sounds such as those in the natural environment, see and remember nonverbal objects such as scenes or pictures, and haptically feel and remember objects, as when we manipulate instruments or gadgets. We can also have nonverbal mental images of familiar tastes and smells. Even our emotions are somatically felt, as in the chill of fear or the flush of romance. DCT is therefore embodied and multimodal in nature because both verbal and nonverbal experiences can occur in different sense modalities including vision, hearing, and touch in the case of language, and all five senses in the case of mental images. In everyday life, our thinking and remembering are often like multimedia events in which language and images occur together; this is a basis of much multimedia educational technology.