Since writing my post in week 3 regarding the myth of the 6 minute video I have been pointed to some more literature on the subject of video design and the length of the video as a design element.
Based on a comparison of the two pieces of research that my blog post also looked at, advisors at UC Santiago came up with the short answer to the question of how long a video should be as
An educational video should ideally be less than 12 minutes long, and definitely no more than 20 minutes long.
(UC San Diego, 2022)
Which is pretty much the conclusion I had come to and aligns with the recommendations in Lagerstrom’s 2015 study. This is essentially double the six minutes recommendation that was drawn from the Guo et al report.
UC San Diego do however acknowledge that the real answer is more complex. Attention span is not necessarily a good measure of video effectiveness and neither is simply measuring how long into a video it is viewed.
The Centre For Teaching at Vanderbilt University look at three elements in order to assess the effectiveness of the video used as a learning tool.
In order for video to serve as a productive part of a learning experience, however, it is important for the instructor to consider three elements for video design and implementation: cognitive load; non-cognitive elements that impact engagement; and features that promote active learning
(Brame, 2015)
Their considerations of cognitive load and in particular the ‘cognitive theory of multimedia learning’, are interesting and argue for thought to be applied to how efficiently we use however many minutes of video we chose to use.
Working memory has two channels for information acquisition and processing: a visual/pictorial channel and an auditory/verbal processing channel (Mayer and Moreno, 2003). Although each channel has limited capacity, the use of the two channels can facilitate the integration of new information into existing cognitive structures. By using both channels, working memory’s capacity is maximized—but either channel can be overwhelmed by high cognitive load. Thus design strategies that manage the cognitive load for both channels in multimedia learning materials promise to enhance learning.
(Brame, 2015)
Positive ways that this theory may be used are by visually signalling important phrases or words that appear in the auditory part of the video, therefore using both channels to convey the same knowledge and maximising the cognitive load.
‘Weeding’ is an act that is also required that removes all extraneous information from the video that doesn’t actually contribute to the learning goal. Too much extra yet unnecessary stuff in the visual or auditory part of the video could distract or cause cognitive overload as the brain tries to make sense of all the information.
This is an interesting theory and one that I did not apply to my own video design. I had included a pile of books as props in both parts of my video.
My colleague on the course, Paul Hughes, had commented that…
I think the way in which you used the various books as ‘props’ throughout your podcast and linked them to your overall lesson plan was alos an almost subconscious delivery which I am sure will influence your learners to research those books without directing them to do so. This directly links with learner motivation and engagement as included within ‘Podcasting for learning in universities’ – Salmon 2008
(Hughes, 2023)
..but I wonder now if the inclusion of the books, which were not directly linked to the achievement of the learning outcome, and other elements in the set such as the rabbit cushion may have been possible causes of cognitive overload. If not in this case then this theory is certainly worth considering in my next video design.
I also need to consider whether just using a ‘talking-head’ as the visual element of the video was the best use of the visual channel. Whilst it made the video quick to make, and introduced the students to me as a person it could be argued that it was a waste of an opportunity to use more relevant, supporting visual versions of the information being conveyed. This theory is called Matching modality and Brame cites a number of sources that back up the argument that video and audio elements of a lecture video should be efficiently used to maximise cognitive efficiency.
Using both channels to convey appropriate and complementary information has been shown to increase students’ retention and ability to transfer information (Mayer and Moreno, 2003) and to increase student engagement with videos (Thomson et al., 2014; Guo et al., 2014).
(Brame 2015)
Reference list
Brame, C. (2015). Effective educational videos. [online] Vanderbilt University. Available at: https://cft.vanderbilt.edu/guides-sub-pages/effective-educational-videos/.
Guo, P.J., Kim, J. and Rubin, R. (2014). How video production affects student engagement. Proceedings of the first ACM conference on Learning @ scale conference – L@S ’14. [online] doi:https://doi.org/10.1145/2556325.2566239.
Hughes, P. (2023). Week 5: Forum – Integrating Activities in Your Flipped Classroom Designs. [online] flex.falmouth.com. Available at: https://flex.falmouth.ac.uk/courses/1154/discussion_topics/28613.
UC San Diego (2022). Video Length: How Long Should a Course Video Be? [online] blink.ucsd.edu. Available at: https://blink.ucsd.edu/faculty/instruction/tech-guide/instructional-videos/best-practices/video-length.html.