The power of teaching using diagrams.
Elen Steadman Head of Geography & ITL Research Fellow
Diagrams are a key component of the teacher’ s toolkit, across most subjects, but why is using diagrams to teach such an effective way of communicating information and what do we need to consider when using diagrams to teach?
Why are diagrams effective?
Fundamentally, diagrams allow us to‘ see the unseeable’. In Geography, some students prefer Human, as opposed to Physical, concepts. This is likely because Human concepts are ones that students are more likely to have been exposed to in their everyday life and hence can easily picture and understand points being discussed. On the other hand, Physical concepts are often more abstract, complex, and, therefore, unfamiliar – it is far less likely students will have seen an erupting volcano than a wind turbine, for example. Other concepts, such as the carbon cycle, are even more abstract to even try to begin to understand, due to both the spatial and temporal scales these processes operate at. Diagrams, particularly in a Physical Geography context, can therefore be exceptionally useful to make unfamiliar concepts more relatable and understandable without oversimplifying or overwhelming students( Taylor, 2024).
Cognitive science principles that explain why diagrams work so effectively
By learning through diagrams, students select, organise and integrate information, according to Mayer’ s SOI model. During learning, students first need to select relevant information from the information they are presented with. This must then be organised into the relevant place within existing schemas of knowledge( essentially mental mind maps or filing cabinets of information) within long-term memory( LTM) and then integrated within these. This final integration step is essential to ensure information is embedded into LTM and does not become forgotten over time. New information is kept in working memory for a few seconds before it is either forgotten or stored in LTM. How easily information is moved into the LTM is dependent on our pre-existing schemas of knowledge. Reading large passages of text can cause cognitive overload and make it harder for new information to be encoded into the LTM. Utilising diagrams makes information easier to process, making it more likely for this information to be assimilated into pre-existing schemas and be embedded into LTM.
Drawing diagrams, alongside verbal instruction, is effective as alongside Mayer’ s SOI model theory, it utilises two other key cognitive science principles- Mayer’ s Cognitive Theory of Multimedia Learning( CTML) and Paivio’ s dual coding theory( Taylor, 2024).
The cognitive theory of multimedia learning:
Verbal information is processed sequentially( we hear and process one word at a time) whereas diagrams are processed synchronously, where we can take in multiple details and see the‘ bigger picture’ at the same time. This allows students to use different sensory channels to process information, thus aiding learning.
CTML has 15 key principles of good‘ instructional design’ which are useful to consider for planning to use diagrams in the classroom. Some of the most pertinent principles include:
• Coherence – simplify diagrams to minimise extraneous load( distractions) for students.
• Signalling – point out specific parts of the diagram to focus on, either during discussion or by drawing the diagram step-by-step in front of students.
• Segmenting – breaking down information to have control over the pace of information delivered.
Dual coding:
The brain is composed of two independent( though interacting) stores – image memory and verbal memory. If we remember something as both a mental image and a word a double memory trace is created. Memories will be retained and retrieved more easily if they are stored in two locations in the brain rather than one, as remembering an image or a word stimulates retrieval of the other. Employing dual coding in the classroom also helps students cognitive load to be reduced and their working memory capacity to be increased, therefore improving learning as encoding information from working memory into long term memory is made easier due to this( Caviglioli, 2019).
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