An introduction to Dual Coding Theory

Hi, I’m Oliver Caviglioli, once a Headteacher and now an Information Designer. Let’s start with two classroom situations in which some students struggle. One is following a teacher’s spoken explanation. Her schema — her understanding of the topic at hand — is in her head and, therefore, invisible to the students. Instead they receive a succession of words and from these have to guess at the content of her schema. Similarly, when a student is reading a piece of text — written by the teacher or someone else — he has to reconstruct the author’s schema in his own head, by use of the text alone. Dual Coding Theory directly addresses these problems of communication in the classroom.

Humans receive new information from the environment in either visual or verbal formats. There are others but these two are the most fundamental. Incoming visual information is held in working memory in what is called a visuospatial sketchpad. And incoming verbal information is held and processed in an auditory loop. Both are limited in storage capacity, and both are separate. These two channels are independent of each other but do form, at moments, links, or associations. When images are linked in this way to words, they enrich the encoding process — otherwise known as learning. A double memory trace is formed, that, correspondingly greatly strengthens the potential for retrieval. Legendary psychologist, Paul Kirschner, calls this double-barrelled learning.

Of equal interest to teachers is the fact that the verbal channel is organised sequentially. That’s to say, words are ordered in line and can only be addressed one at a time. Visual information, by contrast, is what psychologists call synchronously organised. This means that the eye can take in, and understand, many elements at the same time when looking at a simple diagram. Remember that it takes a great many words to accurately describe the simplest of visual images. That should help you realise the power of visuals to communicate complex ideas in the most efficient way to the most number of students.

Because visuals offer this degree of direct access to knowledge, there are a number of benefits when it comes to teaching and learning. As learning is dependent on our attention, visuals’ role in directing students’ attention is significant. It’s far easier to explain something to students when they have a visual focus to channel their attention. Such graphic displays also help trigger students’ prior knowledge — or as we are now describing it, their existing schema. Schema are not organised in the sequential way that speech or text is, but are closer in structure to the spatial arrangements of diagrams.

Instead, then, of wrestling with the fleeting nature of the spoken word and the complex grammar of text, visuals offer students a far more effective way of accessing knowledge. By helping students get a rapid gist of the meaning, they are left with more cognitive resources free to engage in higher order thinking. A direct result of such deeper thinking is the development of students’ own schema. The visual and explicit links found in diagrams stimulate connections between concepts that lead to more meaningful learning. The degree to which such schemas are organised and meaningful, is the degree to which they are easily transferred back into working memory when needed.

Such automatic access to their own prior knowledge, leaves students’ working memory not overloaded and fresh to process new information. Building success in learning in this way, forms the steadiest of platforms for motivation as nothing motivates like success. When creating your own resources with dual coding in mind there are some basic guides that can transform the quality and effectiveness of our endeavours. The first of these is to cut the amount of content you had intended to include on your page or presentation slide. It is the simplest and most effective of all advice you can follow. With your selected content, chunk it. Instead of long sentences across the page, think of how the material falls into different sections.

Give each of these sections a heading that stands out. This is the signalling that greatly helps the reading and understanding process. It needn’t be jazzy — just a bold version of the font, or perhaps in capitals is all it takes. The following piece of advice may sound rather low key, petty even. Make sure everything is neatly lined up. Every single piece of professionally produced page or newspaper or magazine was designed around a grid where images, titles, and text all align neatly. It gives the page an immediate impression of order and gives the reader confidence. Lastly — and this may be frustrating to some — curb your artistic urges. Use fonts and colours with restraint.