We need to talk about dual coding

Dual coding seems to be gaining in popularity. It even made its way into a Deans for Impact blogpost as a way of psychologically manipulating teachers to abandon their belief in learning styles. However, I’m not sure we all have the same understanding of what dual coding actually means.

Essentially, dual coding is based upon the idea that our working memory has separate channels for processing verbal and pictoral information. This has a number of key implications, many of which have been incorporated into Mayer’s Cognitive Theory of Multimedia Learning (CTML).

The “Modality Principle” in Mayer’s theory is essentially the same as Cognitive Load Theory’s “Modality Effect”. This is where, for instance, a physics teacher might explain the function of the components of an electric motor while displaying a diagram or simulation of the motor. The diagram can be processed separately, and in parallel, to the verbal information.

I have two concerns about how ‘dual coding’ might be making its way into the wild.

1. The joy of text

According to CTML, text is cognitively demanding because the text symbols must first be processed in the pictoral channel before being transferred to the verbal channel to be processed as virtual sounds. So if your ‘picture’ component actually has a lot of text on it – for example a concept map or an annotated timeline – you may not enjoy the benefits of dual coding because this text would interfere with the verbal explanation.

2. It’s about teaching not studying

As should be clear, the modality principle is about presenting information to students. It’s not about the best way for students to review material. I am not aware of evidence that doodling pictures while rereading your notes is a particularly effective form of studying but if someone has the evidence for that then I’m happy to be wrong.


10 Comments on “We need to talk about dual coding”

  1. I like your two points — I often see these two issues arise. (I also see people focus on the sensory inputs — the visual and auditory channel — instead of the processing channels — the pictorial and verbal. If you focus on sensory inputs, you end up with precisely the incorrect explanation for what’s going on. Though I’ve also seen Sweller say this in “Story of a Research Program,” which confused me.)

    It even made its way into a Deans for Impact blogpost as a way of psychologically manipulating teachers to abandon their belief in learning styles.

    Here is the quote from the Deans for Impact piece:

    As some learning scientists have aptly observed, dual coding covers similar territory as learning styles. For that reason, advocates of learning science would be wise to introduce dual coding as an alternative to learning styles. We doubt teachers will immediately reject learning styles – students rarely discard their initial (mis)conceptions right away – but over time, if dual coding proves effective in the classroom, teachers may find that learning styles has lost its appeal. Once again: it is better to replace ideas than to debunk them.

    This is not an argument for psychologically manipulating teachers. It’s also not an argument for doing anything to help teachers abandon their belief in learning styles.

    Instead, it’s an argument for introducing dual coding because dual coding is true and meets the needs of teachers who find value in learning styles.

    The GOAL is not abandoning learning styles. The GOAL is helping teachers understand true and useful models of learning. Dual coding is a true and useful model, and it could be useful in some of the ways that learning styles is (false) and useful.

    It’s not a call for manipulation — it’s a call for meeting the needs of teachers with truth, rather than falsity. (And, further, a call for meeting their needs with instruction in true models of learning rather than merely debunking false models.)

  2. eanelson2014 says:

    Two points? First, I think the cognitive science objection to “learning styles” is the claim that “one style is highly preferred for many students.” What cognitive science says is that individual students may be stronger in visual, or spatial, or auditory learning, but for most the differences are relatively small, and that all students need to build links to new knowledge in all of those ways (and more) to maximize the cued recall of knowledge.
    Second, as I read the research, what cognitive science advocates during learning is not simply “dual coding” but “multiple coding.”
    Sweller writes: “The function of learning is to store large amounts of information in long-term memory so that it can be brought effortlessly into working memory enabling us to function in a large variety of complex environments.” (Tobias & Duffy page 137) What enables knowledge to be recalled from LTM are the linkages that grow when the neurons that store knowledge fire at close to the same time in WM during problem solving. The rule is: “neurons that fire together, wire together.”
    When solving a problem, the cues in data activate LTM neurons storing the cues, which in turn to varying degrees activate all of the linked neurons, and the information stored can then be “brought effortlessly into” WM and applied to solve the problem.
    So what cognitive scientists advocate is to promote growth in LTM wiring to new information not just based on how you hear it, or what it looks like in 2D and 3D, but on where you see it, and how you write it and say it, and where it occurs in a sequence, and whether you treat it as a noun or a verb or adjective, etc. In some cases, we want students to remember what it smells like (ammonia, gasoline, natural gas).
    The way we teach students to build this recall is to create situations where they solve problems using new knowledge in a variety of distinctive contexts.
    In other words, the rules for Cognitive Load Theory and the Cognitive Theory of Multimedia Learning, most developed empirically over the past 30 years, can be explained by what we have learned more recently about the physiology of cognitive architecture. Clark, Sweller, and Kirschner reference this in their 2012 American Educator article.
    For a bit more on the physiological basis for limiting cognitive load, see PDF pages 3-7 at http://nonpartisaneducation.org/Review/Articles/v13n3.pdf
    — rick nelson

    • Greg Ashman says:

      In this case it really does mean ‘dual’ because it is based on the idea that there are two channels in working memory.

      • eanelson2014 says:

        Baddeley modified his 1986 “2 slave” model in 2000 to include the “episodic buffer.” See


        The episodic buffer is needed to explain tasks including the speech comprehension, which is primary (highly instinctive) learning in humans.

        But obviously WM and LTM need to be able to store smells and textures and tastes that are learned. Those don’t get studied much, probably because they rarely have impact on academic learning. The episodic buffer, on the other hand, handles sequence, which is important in many academic problem-solving procedures.

        There is also evidence that the “visio-spatial sketchpad” that is in most working memory models does handle some visual and spatial components separately (see the ref above)

        None of this changes the fundamental and key rule that working memory is very limited when processing non-memorized knowledge, but essentially unlimited in recalling and processing information that the learner has previously memorized and linked to other memorized knowledge that can serve as recall cues.

        Initial memorization “to automaticity” by the learner is vital to move initial elements of knowledge into memory, because a neuron cannot be linked until knowledge is memorized — stored in the neuron. The impact of those who deprecate initial memorization of new elements of knowledge is to handicap student learning.

        – rick nelson

  3. Ad “2. It’s about teaching not studying”
    This may hold true for the modality principle, but the dual coding theory offered by Paivio leaves it open, how and when in the learning process dual coding is used. Admittedly, just “doodling” whatever while reading your notes will not help, but so wouldn’t “jot down” whatever while re-studying diagrams. If text and diagram were included correctly in the first presentation (by a teacher or read in a book) of information, the learning is definitely better – so the same could be at least assumed for studying the subject again later.

  4. I think that you actually have a point regarding “doodling”, on the other hand. If in practice the core idea would be translated into “just doodle it”, this could turn out to be not helpful, even lead to effects, which are contrary to the intention.

  5. James Townrow says:

    Hi Greg,
    In this and in previous posts, you have discussed written words being transferred from the visual channel to the auditory/spoken word channel via an “inner voice” – which intuitively feels correct.

    However, in Paul Kirschner & Mirjam Neelen’s summary of dual coding (https://3starlearningexperiences.wordpress.com/2017/05/30/double-barrelled-learning-for-young-old/), the implication seems to be that the text is handled by the visual channel only (In our brain written and spoken words only get coded once”)

    The explanatory videos that Kirschner and Neelen link to imply the same (https://www.kuleuven.be/english/education/educational-policy/limel/training-platform/script/the-cognitive-theory-of-multimedia-learning and https://www.youtube.com/watch?v=6CPNLwKmWpc), The first video even explicitly states that “written words are registered in the visual part of our sensory memory” with no mention of the cross over to the auditory channel. The second implies that it is visual channel that gets overloaded when watching image + text + audio.

    Have I missed something here (entirely likely)? If you have time to comment I’d be extremely grateful.



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