Cognitive Theory of Multimedia Learning
In a nutshell, people learn through two channels -- words and images. This dual-channel theory suggests that people process auditory and visual stimuli separately. Each channel requires time to process information before merge into a cohesive cognitive concept.
Dual Channel Theory for Multimedia Learning
(click to enlarge)
Based on this dual-channel theory, Mayer developed some key principles in designing multimedia materials. The key is to minimize cognitive load, or the burden on one's working memory during instruction. Some examples from the highlighted article include:
- Make the message stick: Simplify using images. Get the message across by making the header a sentence rather than a phrase. Avoid bullet points.
- Signaling principle. Highlight only the essential material.
- Coherence principle. Avoid distractors and eliminate unnecessary words, pictures, and sounds.
In a prospective study this month from Medical Education, traditional Powerpoint slides were compared to modified Powerpoint slides in a lecture on Shock. The content remained the same. The modified Powerpoint slides implemented Mayer's multimedia design principles. Many other principles are nicely summarized at Design eLearning blog. A convenience sample of Surgery clerkship third-year medical students were enrolled (n=39 traditional, n=91 modified).
Based on a pre-test/post-test design, the authors found that the students were able to recall facts better (eg. "Define shock.") using the "modified" Powerpoint slides. Interestingly, the "modified slides" students did not perform any better than the control group in their ability to transfer their knowledge in written clinical vignettes.
This was a great study. I hope they pursue this line of inquiry. More studies need to look at using multimedia effectively for teaching.
In the meantime, I am definitely going to be reading more about Mayer's work.
Reference
Issa N, Schuller M, Santacaterina S, Shapiro M, Wang E, Mayer RE, Darosa DA. Applying multimedia design principles enhances learning in medical education. Medical Education. 2011; 45(8), 818-26. PMID: 21752078
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