- Title: When and how to use visuals effectively: a meta-analysis of dual coding in the classroom
- Authors: Briony Banks, Jennifer Curran, Rebecca Hall, Sam Sims & Stefanie Meliss
- Access the original paper here
- Watch a video overview:
Paper summary
A team at Ambition Institute pooled 56 randomised experiments, all run in real schools, to test whether adding visuals such as pictures and diagrams to spoken or written explanations helps pupils learn. Across 189 results from 6,675 pupils, from early years to Year 13, visuals had a moderate positive effect on learning. The benefit was much larger for secondary pupils than for primary pupils, and larger in whole-class teaching than in small groups. Effects were biggest when visuals were explicitly linked to the explanation, when content was broken into meaningful chunks, and when irrelevant details were left out, although these differences were not statistically certain. The benefits showed up in tests taken within a week, but had disappeared in the seven studies that tested pupils two or more weeks later.
If teachers remember one thing from this study, it should be…
Visuals help pupils learn, and secondary pupils gain the most. Gains were largest when the visual was pointed to and talked through during the explanation, content came in chunks, and anything irrelevant was cut. The benefit had faded after two weeks, so plan to come back to the content.
*** PAPER DEEP DIVE ***
What are the key technical terms used in the paper?
- Dual coding: pairing a visual with spoken or written words.
- Signalling: explicitly linking the visual to the words, e.g. pointing or annotating.
- Segmenting: breaking content into meaningful chunks.
- Coherence: leaving out irrelevant details.
- Transfer: applying learning to a new, untaught problem.
- Meta-analysis: combining many studies’ results into one estimate.
What are the characteristics of the participants in the study?
The review pooled 56 randomised experiments run in mainstream schools: 189 results from 6,675 pupils, split evenly between primary and secondary. Most studies were American (32), used pictures or diagrams, taught science or literacy, lasted one lesson, and were delivered by researchers rather than class teachers.
What does this paper add to the current field of research?
Most dual coding evidence comes from lab studies with university students. The EEF’s 2021 review of school-based studies found mixed results but didn’t pool them. This meta-analysis includes only randomised classroom experiments, and compares several design principles side by side where earlier meta-analyses examined one at a time.
What are the key implications for teachers in the classroom?
- Talk through the visual while it is on the board. Of all the design choices tested, signalling looked the most powerful. Visuals that were explicitly linked to the explanation had more than double the effect of visuals that weren’t. In practice, point to each part of the diagram as you name it, and label the diagram with the same words you use when explaining.
- Build visuals into whole-class teaching for everyone. The authors expected visuals to work best with small groups or individual pupils. They found the opposite. Effects were much larger in whole-class teaching than in small groups, and also larger on average than one-to-one. Visuals also helped more when the teacher set the pace than when pupils worked through material at their own speed. So the diagram belongs in your main explanation to the whole class, rather than on a help sheet handed to the few pupils who seem stuck.
- Expect secondary pupils to gain more, and think carefully about how you use visuals in primary. Visuals helped at every age, but the effect for secondary pupils was over three times the size of the effect for primary pupils. For primary pupils, visuals helped them remember what was taught, but showed no benefit for applying that learning to new problems. If you teach younger children, a picture may help them hold on to a story or a fact, but don’t assume it will help them use an idea in an unfamiliar question. That still needs teaching and practice of its own.
- Strip out decoration. When materials contained irrelevant details, the benefit of the visual shrank to the point where it was no longer reliably positive, and the authors warn it may even harm learning. The paper’s example of a decorative visual is a picture of a dinosaur next to a maths problem. Before using a slide or worksheet, ask of every image whether it helps explain the content. If it’s only there to make the page look nice, delete it.
- Present content in chunks, and pause between them. Segmented content had roughly double the effect of content delivered in one continuous block, and the authors link it especially to helping pupils understand. On a slide, that might mean revealing a process one step at a time with its matching part of the diagram. When explaining out loud, it means stopping between steps instead of running through the whole thing in one go.
- Be wary of asking pupils to copy, colour or label diagrams. It is common advice that pupils should physically work with a visual. In this review, eight of the 16 studies that asked pupils to do something with the visual (copying, filling in a diagram, clicking or dragging on screen) found negative effects. The authors point out that four of those eight studies tested pupils weeks later, which may explain some of it. Even so, if pupils spend ten minutes copying a diagram, it’s worth asking whether that time would be better spent on you explaining it while they watch, followed by questions about it.
- Spend less time worrying about exactly where the image sits. Placing visuals right next to the text they go with, or showing them at the same moment as you speak, made only a small difference. If prep time is short, it is better spent on signalling and cutting clutter than on getting the layout perfect.
- Plan to come back to the visual. Benefits were clear in tests taken straight away or within a week, but had vanished in the seven studies that tested pupils two or more weeks later. A diagram in today’s lesson is unlikely to make the learning stick on its own. Bring the same diagram back in later lessons, ask pupils questions about it, and use it to recap before building on the content.
Why might teachers exercise caution before applying these findings in their classroom?
Most studies were one-off lessons run by researchers using their own materials and tests, so effects in everyday teaching may be smaller. Results varied hugely between studies, and most differences between approaches weren’t statistically reliable. Few studies looked at maths, pupils with SEND, or learning beyond a week.
What is a single quote that summarises the key findings from the paper?
“We found that dual coding benefits learning at all ages but more so for older pupils. Particularly, it may have no effect on primary pupils’ transfer. Using relevant visuals can help pupils to retain and understand information in the short term, but we found limited evidence of long-term benefits.”
