This material was completed as part of a time-controlled assignment for the Chartered College; it contains less references than I like to include but the theory is sound; I may return to this blog to add detail and to add references.
Question 1: Provide a brief summary of your chosen pedagogical approach, explaining the key ideas and including relevant theory, research and evidence to support your explanation, where appropriate.
Dual coding relates to how information is presented to students in order to maximise their understanding. If done well, working memory capacity can be effectively increased, and learning improved, by using a dual-mode presentation" (John Sweller, 1988). However, we should note that working memory is not increased, students make better use of the two channels available to them in their working memory. This is important because in our current understanding of how learning happens (in brief, students transfer information from their surroundings if they pay attention to it and select it. This is processed alongside information from the long-term memory. Information is then encoded in the long-term memory) the working memory has very limited capacity. This might as low as four pieces of information (Cowan, 2010).
In the model for dual coding, the working memory has two channels. The first processes visual information which by its nature is synchronous. The second processes verbal information which is sequential. By presenting both visually and verbally the student can utilise both channels with associations being formed across those channels. This ultimately means that the student stores two sets of information and therefore has two opportunities to retrieve the information.
So, student understanding benefits from information being presented in diagrams alongside an auditory explanation. However, there are many pitfalls to the use of dual coding.
Question 2: What are the strengths and limitations of this pedagogical approach that teachers of your subject, phase or specialism should be aware of?
Dual coding has a number of pitfalls that span all subjects and phases. However, my subject is secondary science as so I will refer to this in this question and the following question.
Science is a complex subject with large amounts of knowledge that needs to be built in a hierarchical fashion in order that students build accurate mental models. The large numbers of interconnections between concrete and abstract information means the use of images is invaluable as these show synchronous information. Indeed, the best images for use with dual coding show the underlying relationships between pieces of information (Gyselinck and Tardieu, 1999). These are helpful because they give students a good representation of what they are trying to construct in their mind.
However, we need to consider carefully the information that accompanies any diagrams or images used. It is tempting to use writing on slides next to images. If this is to be done, the writing must directly relate to and enhance the image. The use of the image alongside text is known to improve learning beyond that achieved with text alone (Butcher, 2006). However, a better method is to use images with auditory explanations alone (Herrlinger et al, 2017); the danger of using text is that the visual channel becomes overloaded as it processes the image and the text.
We also need to consider carefully the type of image or diagram used. Some images, such as those showing a phenomena rather than explaining a phenomena, whilst popular with students, can be detrimental to learning. Decorative images can contribute to extraneous cognitive load and also be detrimental (Mayer et al, 2001). So images need to represent the ideas and the relationships between them whilst minimising extraneous load. Text, if used, needs to be placed alongside the images rather than being separated in time; temporal separation reduces the impact (Mayer and Sims, 1994).
A further issue is that experts (e.g. teachers) make more inferences from images than novices. So, the teacher needs to put themselves in the place of the novice and plan the explanations that will work with the text to maximise understanding (Suws & Tversky, 1997).
Question 3: Identify one specific concept or skill taught within your subject / phase / specialism and explain how you would use your chosen pedagogical approach to support pupils’ learning in relation to this concept or skill.
Within your response you should:
● identify the specific concept or skill you have chosen to discuss
● describe the steps you would take to teach this concept or skill using this pedagogical approach
● highlight how you would build on prior learning where relevant.
● highlight any typical misconceptions or common errors and explain how you would address these
The specific concept that I am choosing is changes of states of matter and how we explain the changes in properties observed using the particle model. .
The particle model is highly abstract. It is introduced at KS3, however, primary schools often introduce it when teaching properties of each state. This is problematic as misconceptions are often introduced at this point. For example, the particles in a liquid are in close proximity, however, students are often taught that they are spread out (but less so than in gases).
The prior learning that students often have when they join us, that is useful, is knowledge of properties of solids, liquids and gases .This helps them to identify each state. The lesson sequence would always start with a pre-test to find out exactly what students can recall in terms of properties (key properties are often missed at primary school). Students would then be asked to classify a selection of solids, liquids and gases and to explain their ideas using their knowledge of properties.
I would then introduce key properties that underpin later study and use explicit instruction to demonstrate these. It is important that students have an accurate understanding of these properties hence explicit instruction.
At Ks3 students need to explain why substances have these properties using the particle model. At this point, the concept of particles is introduced. The distribution of particles in solids is introduced in a diagram; the particles are close together and in a regular arrangement. The teacher also explains that the particles are held together by strong forces so they only vibrate (an animation is useful here). The link is made to compressibility, fixed shape etc.
Gases are the next simplest state to understand. So again, the distribution of particles is shown in an image. The teacher explanation needs to focus on the space between the particles (so gases can be compressed as the amount of space can be decreased). In s also helpful to use an animation to show that the particles move in random directions at radon speeds. The teacher gives description and explains that this allows particles to fill a space.
Finally, liquids are studied (this is associated with most misconceptions (e.g. particles in liquids are spread out). The lack of compressibility is revisited (by demonstration). Images and animations are used to show that the particles in liquids are close together and so they are hard to compress. However, liquids can flow because the particles roll over each other.
The key to students using the particle model is that they have accurate images of particle distribution. Also, that the teacher has carefully thought about how to describe the images / animations and then move to using this to explain properties (supported by demonstrations). Without careful use of dual coding the students would not develop foundation knowledge that is key to understanding all of chemistry and large parts of physics.
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