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.