Sunday, July 18, 2010

Dual Coding Theory and Teaching

Dual Coding
by Susan Codone

Allan Paivio initially proposed Dual Coding Theory in 1971 to explain his view of how we remember pictures and words.  The Stanford Encyclopedia of Philosophy describes Dual Coding Theory as one of the most influential theories of cognition in the 20th century. Paivio states that his theory of cognition has roots in the practical use of imagery as a memory aid going back over 2500 years (Dual Coding Theory and Education, 2006).  In fact, he says that memory is crucial to Dual Coding Theory because it is the basis of all knowledge and thought.

Paivio argues that there are two ways a person can elaborate on material.  One form of elaboration uses verbal associations; the other form creates a visual image to represent a picture or word.  Paivio says that pictures result in better memory and the potential of imagery is a more reliable predictor of learning than words.  Dual Coding Theory proposes two independent memory codes which together increase the chance of successful information retrieval.

Teaching with Dual Coding Theory
Richard Mayer, who has proposed the Cognitive Theory of Multimedia Learning, borrows the concept from Paivio that the learner possesses both a visual information processing system and a verbal information processing system (Richard Mayer and Roxana Moreno, A Cognitive Theory of Multimedia Learning: Implications for Design Principles, 2005).  Both he and Paivio apply their theories in teaching by saying that whenever you teach a concept with words, pair it with an associating picture in order for your students to more easily transfer it from working memory to long-term memory.  For example, the two PowerPoint slides below illustrate this principle; the first is text only, while the second uses the most important text along with a relevant picture of what is being taught.

We all know that text-only slides are not as effective as a slide with text and a relevant picture.  In teaching, though, our use of pictures and text goes beyond teaching efficiency; by offering students both mediums, we open two channels into their working memories, thus laying down more solid neural pathways and making later retrieval much easier.  We make it easier for them both to learn and to recall information later when we use two channels of presentation.

Take a look at this screen grab from a medical e-learning course from Interact Medical.  This particular screen displays text on the left with an explanatory picture, including labels, on the right.  Now, medical education is very dependent on pictures, but this slide is actually more efficient than most; the text on the left "primes" the user to understand the picture on the right, and the picture confirms the message of the text. In the event the student looks at the picture first, the opposite effect occurs -- one pathway is laid down and the student next associates the text with the picture.  Both the visual and verbal information processing systems are invoked in the learner and the message of the text and the image both go together into working memory, linked by association as they eventually move into long-term memory.  The learner can then more easily retrieve the message by recalling the text and the picture, because both are linked by association in long-term memory.

Paivio says that images are more effective in both encoding into memory and retrieving from memory because an image provides a "'second kind of memory code independent of verbal code".  Mayer, in his research on multimedia and cognition, builds on Paivio's work by offering several principles of multimedia learning, the first of which is that it is better to present an explanation in words and pictures than solely in words.  Mayer says there is a multimedia effect consistent with a cognitive theory of multimedia learning because students shown multimedia explanations are able to build two different mental representations -- a verbal and visual model -- and build connections between them.

If you don't know what a kangaroo is, which picture is better?

Dual Coding Theory has great implications for teaching and learning.  Essentially, we do our students a favor when we offer multiple presentation modes to them while teaching -- we make it easier for them to acquire the  information, make associations, store it in working memory, transfer it to long-term memory, and then recall it later.  As professors, we can be better informed by the use of this theory, and our students will benefit.

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