Dual coding, which is the process of blending words and pictures together, allows students to learn and recall information better. However, a separate area of psychology, the Redundancy Effect, suggests that including excessive and/or irrelevant information can hinder learning. Does this mean that dual coding could be in conflict with the Redundancy Effect?
Let’s start by taking a closer look at what dual coding and the Redundancy Effect are, why this might happen and how to use the two in tandem together.
A big thank you to Stephen Chiger for coming up with the topic for this blog and helping us write it – make sure to follow him at @SteveChiger!
What is Dual Coding?
Dual coding consists of using both words and picture when learning. This presents students with two different representations of the same piece of information, which helps cements the information deeper into their long-term memory, as essentially there are two entry points to the brain for this information.
In one study that investigated this, students were given just words, just pictures, words then pictures or words and pictures together. The researchers found that:
- Students performed 50% better in the test when they were given both pictures and words compared to those who were given words alone.
- The students who learnt using both words and pictures remembered around 50% more than those who revised by seeing words and then seeing pictures.
Therefore, being presented with both words and pictures when learning helps improve students’ memory and recall.
What is the Redundancy Effect?
An interesting area of Cognitive Load Theory is the Redundancy Effect. This happens when students are given irrelevant information during the learning process, which clogs up their working memory. As a result, students are more likely to remember the wrong information, as we can’t be sure which bits will transfer to their long-term memory.
Examples of the Redundancy Effect include:
- Too many words on a PowerPoint slide
- Excessive PowerPoint animations
- The teacher talking about something else whilst students do a task
- Repeating written down instructions orally (this can create redundancy as people read and listen at different speeds)
Why might Dual Coding create a Redundancy Effect?
Here's where things get tricky. If we can create a cognitive overload by pairing identical on-screen text and narration, don't we run the risk of doing this when we pair text with images?
Although the research on this is still being developed, the answer to this appears to be yes. This is especially true if the textual information is redundant or the images are irrelevant. Whilst we might be able to enhance learning by providing an additional visual format, if it winds up repeating what we're already saying, we may be hindering learning.
So, how can we avoid this?
Tips to use dual coding effectively1. Curate your content: Avoid repetition and irrelevance
Don’t read text off a PowerPoint slide or a diagram as it doesn’t help students process the information well. Instead, cut out any repetitive information, making sure that each format only presents the information once.
One way to do this is to ensure that the audio and visual information work in partnership. This helps the information flow well together, making it more useful for students’ learning.
2. Send up a signal: Cue students into what matters when load is high
To help avoid students having a cognitive overload, it might be useful to direct their focus on what matters. Research suggests that one way to do this is by providing signals that helps learners direct their focus and organise information.
One way to do this is by using note-taking organisers when showing videos to students, as it can help them know what to focus on.
3. Know your audience: Tailor your presentation based on student expertise
It is very important to keep students’ prior knowledge in mind when teaching a topic. If students are presented with information they already know, it can create a Redundancy Effect. One way to find out how much prior knowledge students have is by constantly having mini-quizzes to check their understanding and asking them to summarise the information.
While dual coding theory has had many years of scientific study, its full implications for classroom practice are still being studied. But that doesn’t mean teachers shouldn’t use it. It means we should be selective and critical of how we use it. Whilst dual coding and the Redundancy Effect may seem initially at odds, with a little planning, both can be entirely compatible.