Dual Coding Part 1 – Origins and Theory
In this blog, Elliot Morgan gets to grips the origins and theory behind Dual Coding. This blog is Part 1 of a 3 part series on Dual Coding, and its implications for the classroom.. A video explanation of this blog can be found at the bottom of the page too.
Dual Coding Theory (DCT) was formulated by Allan Paivio in 1971. It was influenced by various studies in the 50s and 60s, which proved that free recall of images was higher than the recall of their word labels.
This led Paivio to suggest that pictures were “more effectively stored in or retrieved from long-term memory” and “better retrieved from short-term memory” than words (Paivio et al, 1968, p.138).
Paivio had previously won a ‘Mr Canada’ bodybuilder competition, so it is rather fitting that he would later formulate a theory that focused heavily on image.
The theory intended to explain the effects that mental imagery could have on our memory. Traditionally, theories on memory suggested that the speed through which we were presented stimuli, or how we connected them together, would determine our ability to later retrieve them from our memory. DCT challenged this notion, instead suggesting that the modality (how the stimuli is presented) is what affects our memory.
Over time, DCT became applied to cognition instead of memory, seeking to explain how we acquire knowledge through the process of thought, experience, and our senses.
Where does Dual Coding get its name from? Well, ‘dual’ means consisting of two parts and ‘coding’ means moving to memory – so essentially, the theory concerns two ways of moving information to memory (through verbal and nonverbal representations).
Verbal representations include written or spoken word. Nonverbal representations usually pertain to images or physical objects (visual stimuli).
Paivio believed that our brain’s ability to code information both verbally and visually would increase our chances of remembering it, compared to if it were coded in only one way (just verbally or just visually).
Let us consider this theory of Dual Coding with relation to traffic signs and the driving theory test.
When revising for the theory test, you learn what individual road signs mean. Your brain dually codes the information; you combine verbal information (what the sign means) to specific visual information (what the sign looks like) and vice versa.
When it eventually comes to the test, and you are presented with a picture of the road sign, you are more likely to recall the verbal representation than if you did not dually code, because the memory trace is stronger – you coded the picture and its meaning together.
The theory implies that if our brain cannot make associations between a verbal stimulus and a visual stimulus, the information will be harder to ‘code’ and consequently harder to recall at a later point in time.
Therefore, the underlying principle of DCT is that our memory of something is enhanced if it is presented to us as a combination of verbal and visual representations.
Dual coding can only occur if verbal information is presented alongside a relevant visual stimulus, or if the recipient of the information can imagine a visual image that is relevant. Likewise, visual information will be enhanced only when paired with relevant verbal information (watch the attached video below for an example of this).
If the accompanying verbal or visual representation is not relevant, it will mean the information is not understood together and therefore cannot be dually coded successfully. Moreover, the more apposite the visual representation is, the stronger the coding of the information will be together.
Paivio also argued that if you code information together in these two modes, it allows you to access more capacity in your working memory. By coding information in two ways, it is easier to retrieve from our long-term memory as there is a double trace (a verbal representation and a visual representation).
Being able to retrieve information from our long-term memory will allow us to free up space in the working memory and allow us to focus our cognitive efforts on other information instead.
The Two Systems: Verbal and Nonverbal
The verbal system deals specifically with language, enabling us to decipher language and eventually code it to long-term memory. This system usually processes verbal information sequentially (one after another). Just like you brain is doing now, as it reads this sentence, you are reading and interpreting one word after another. Although usually sequential, the verbal system can also process in a serial manner, going back to different parts of verbal information that have already been represented. Like is done when you read a paragraph – you may revisit a word earlier on in a sentence or the paragraph itself.
The nonverbal system can also process language, but through use of imagery and visual metaphor (Paivio, 1986). It also processes physical movement (e.g. gesticulating) and environmental sounds (e.g. a whistle in PE). When thinking about teaching, it is most commonly associated with the processing of pictures and objects.
Paivio believed this system processes information synchronously (at the same time), or in parallel, as all parts of imagery are simultaneously accessible (Paivio, 1986). For example, if we are presented a picture of a heart in a science lesson, our brains are able to take in all parts of it at once, rather than have to visit each section one after another. This system is also known as the ‘visual’ or ‘imagery system’ because its main function is related to the production of mental imagery (Sadoski, 2003).
As this system can process different parts of an image simultaneously, it is believed that imagery has an advantage over text, as it is more easily processed, with less time and effort. We can also manipulate visual representations in our mind, such as rotation or tilting a model (Clark and Paivio, 1991). Paivio believed that cognition was defined by the “interplay of the two systems according to the degree to which they have developed” (Paivio and Clark, 2006, p.3). This interplay helps to define the types of processing that DCT supposes.
The Three Types of Processing
The representations we form in our mind are connected to the sensory input of how the stimulus is taken in. For example, in attempting a word-search or crossword, the verbal system would dominate. We see words on the page and mostly think about words. In contrast, when attempting to complete a jigsaw, the visual system would dominate.
We see images in front of us and think mostly of images. Verbal representations often represent something conceptually, rather than perceptually.
For example, I may represent the letter ‘x’ in my head as a value in algebra, a kiss in a text message or as the place where treasure is buried.
In contrast, visual representations are often a near-exact representation of what we see. Paivio (Clark and Paivio, 1991) said that “imaginal representations are analogous or perceptually similar to the events that they denote” – so in the mental image of a book in my mind, I be able to see the embossed lettering, the hard spine, the individual pages and so on. These visual and verbal representations form three types of processing: representational, referential and associative.
1. Representational processing
When I see the word ‘dog’ written down, I think of the word ‘dog’ in my mind. Likewise, we may see a triangle in front of us and that same triangle is represented in our mind.
2. Referential processing
The two systems join and “potentially allow such operations as imaging to words and naming to pictures” (Clark and Paivio, 1991, p.153).
It is important to emphasise here that the information does not just move across, it triggers a different type of representation in the other subsystem. It transforms a stimulus, rather than just transporting it across.
3. Associative processing
These associations could also arise through “connections between instance and category names (e.g. gold, lead, iron acquiring link to the term metal)” (Clark and Paivio, 1991, p.153). Likewise, seeing an image may make us think of other images, like a football prompting the image of a goal or a favourite player.
It is through these three types of processing that the information is interpreted, acted on and eventually stored in our long-term memory for later use.
What key points should we reflect on so far?
- Dual Coding concerns two ways of moving information to long-term memory (verbal and nonverbal).
- For something to be dually coded, it must form two representations in our mind (most commonly a word and an image or object is used).
- Something is more likely to be remembered if it is dually coded than single coded, as it creates a double memory trace.
- When presenting verbal and visual stimuli together, they must be relevant to each other. If not, the recipient will not comprehend the link and therefore not dually code the information together.
- Dual coding can help to free up space in the working memory.
- There are two subsystems that process information – the verbal system and the visual system.
- The two systems can represent information independently and link to similar information within their system or they can trigger each other to form representations.
In part 2, we will consider how Dual Coding Theory has influenced other cognitive theories and how it has developed itself. The third part will discuss how we can use what we have learnt from part 1 and part 2 in our classroom practice.
Dual Coding – Theory and Origins Video
- Bousfield, W.A., Esterson, J. and Whitmarsh, G.A., 1957. The effects of concomitant colored and uncolored pictorial representations on the learning of stimulus words. Journal of applied psychology, 41(3), p.165.
- Clark, J.M. and Paivio, A., 1991. Dual coding theory and education. Educational psychology review, 3(3), pp.149-210.
- Ducharme, R. and Fraisse, P., 1965. Genetic study of the memorization of words and images. Canadian Journal of Psychology / Revue canadienne de psychologie , 19 (3), p.253.
- Lieberman, L.R. and Culpepper, J.T., 1965. Words versus objects: Comparison of free verbal recall. Psychological Reports, 17(3), pp.983-988.
- Paivio, A., Rogers, T.B. and Smythe, P.C., 1968. Why are pictures easier to recall than words?. Psychonomic Science, 11(4), pp.137-138.
- Paivio, A., 1975. Perceptual comparisons through the mind’s eye. Memory & Cognition, 3(6), pp.635-647.
- Paivio, A., 2014. Intelligence, dual coding theory, and the brain. Intelligence, 47, pp.141-158.
- Paivio, A. and Clark, J.M., 2006, September. Dual coding theory and education. In Draft chapter presented at the conference on Pathways to Literacy Achievement for High Poverty Children at The University of Michigan School of Education.
- Paivio, A. and Walsh, M., 1993. Psychological processes in metaphor comprehension and memory.
- Sadoski, M., Goetz, E.T., Stricker, A.G. and Burdenski, T.K., 2003. New findings for concreteness and imagery effects in written composition. Reading and Writing, 16(5), pp.443-453.