There is a yin and yang effect between visual and auditory attention. When one is looking, then auditory processing areas go down, and when one is listening, then visual processing areas go down. Mixed visual-auditory stimuli have an underadditive effect, so that if you have to do both at the same time, total brain activation goes down....
In Ruth Clark's book e-Learning and the Science of Instruction, we learned not to ask a channel to multi-task. For instance, don't show a detailed animation and have text on the screen with an audio narration. That's an overload of the visual channel.
So it's interesting to think about this underadditive effect where "total brain activation goes down" if presenting in both visual and auditory at the same time. I don't think the answer is to only show a visual, or only have audio. Otherwise, what's the point of multi-media? Is multimedia the same as multitasking?
4 comments:
Maybe the "underadditive effect" occurs when a multimedia presentation does all the thinking for you. I couldn't see the original citation (maybe a bad link) but I can easily imagine a visual-with-audio presentation that requires no actual thinking on the part of the learner. Popular belief about TV is the same: TV supposedly depresses brain function because it's so passive. I don't know if this has been supported by research.
I've seen a lot of over-teacherly animations that end up being boring. They often use slick video to show a concept while a voice-over explains everything, so the learner's only role is to passively absorb.
A single-mode presentation of the same material might stimulate some thinking and improve long-term retention. For example, visuals with minimal explanation would require the learner to participate more in creating sense of the materials.
I'm not saying to leave the info a mystery; I'm saying that I've seen a lot of elearning that seems to underestimate the intelligence of the learner and makes every little thing painfully explicit. This leads to passivity and boredom.
Research cited in Clark's books supports the notion that requiring the learner to build some connections themselves increases their long-term retention. This can be done through a slick multimedia presentation that would otherwise be passive. For example, asking the learner to predict what would happen next or showing a metaphor rather than immediately explaining everything would involve the learners and help them build their own connections.
I had questions after reading the Eide post this morning too. I haven't gone through their citations yet, but I wonder if part of what was being tested was having identical information presented in both visual and auditory channels. If they were showing exactly the same in both, then what Clark & Mayer say agrees with what the Drs. Eide say. However, if the research found brain activity down while having audio narration with a visual like a graphic or animation where the content complemented rather than duplicated, that contradicts the whole cognitive overload theory.
I'm not sure what to make of it, honestly. If you figure it out, please post it!
@ Cathy: I fixed the link -- sorry 'bout that.
And thanks to both of you for your insightful comments! I do think it's all about building connections for our learners, not creating passive experiences in which no actual thinking is required.
To Christy's point, I think it's important to note the format of the study. Were the video and audio identical?
I'll do some more sleuthing and see what I come up with....
Lesson learned here. It sure pays to read the study referenced. Although, I must say, reading academic studies is like reading another language! I'm way out of practice...
The Just study referenced by the Eide's is really about multi-tasking. Here's my simple interpretation:
Participants were presented with two inputs/problems, one visual the other auditory.
The visual task involved a "mental rotation"; looking at complex 3D figures and determining if they were the same or different from each other.
In the auditory task, they heard a sentence (e.g., "Botany is a biological science...") and had to identify if it was true or false.
At first, participants were instructed to only solve the mental rotation task (visual) and not pay attention to the sentence.
Second instance they were told to answer the auditory task but not solve the 3D visual task.
In the third instance, they were told to pay attention to both and respond to both.
It seems to me since the visual task and the auditory task had no connection to each other, that we're talking about multi-tasking here -- and NOT about cognitive load or effective presentation of information in a learning environment.
Phew. That's my research for the day.
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