Dual Code It
Draw a simple visual while you explain, so students hear the idea and see it too
What is it?
Dual Code It means pairing a difficult explanation with one simple visual drawn as you speak: a timeline, a labelled diagram, a sketch with two axes. The mind takes in spoken words and images along partly separate channels, so a well-matched pair can carry more of the idea than either would alone. You build the drawing live because an image that grows alongside the explanation is easier to follow than a finished diagram presented all at once.
The steps
- Choose the shape before the lesson. Decide what you will draw. A timeline suits events, a labelled diagram suits parts, and a two-axis sketch suits two things that change together. Draw it once on paper to check that it fits on one board.
- Start with an empty board. Begin the explanation with nothing drawn, and add the first mark as you say the first sentence it belongs to. A drawing that appears piece by piece shows students where to look.
- Match the pen to the words. Draw each part at the moment you are explaining it. Write a label, then say it aloud. When the image and the sentence make the same point at the same time, each strengthens the other.Watch the pen. As the water warms, I draw this arrow going up: that's evaporation, water leaving the sea as vapour.
- Keep every mark meaningful. Use lines, boxes, arrows and short labels, and add a mark only when it shows part of the idea. A diagram that a student could copy in under a minute is about the right size.
- Ask students to read the picture. Pause once or twice during the build to ask questions about the drawing itself. The answers tell you whether the picture and the words are carrying the same idea.Look at this arrow. What is it telling us, Ayesha?
- Have students turn the picture back into words. Close by taking the words away: ask the class to retell the whole explanation from the drawing alone, or to redraw it from memory with every label. Either task makes students rebuild the idea for themselves.Books closed, eyes on the diagram. Use it to tell your partner the whole story, start to finish.
What it looks like
Mr Garside's history class of 13-year-olds is encountering Weimar hyperinflation. The board holds two ruled lines: years along the bottom, the price of a loaf of bread up the side. "1919. Bread costs about one mark." He marks a dot, low down. "By 1922, over a hundred." A higher dot follows, and the line between them climbs as he talks about reparations. By November 1923 the price is off the top of the board, so he draws an arrow and writes "200 billion marks" beside it.
Then he notices a dozen students copying furiously instead of listening. "Pens down. You'll redraw this from memory at the end." In the last five minutes he asks, "Amara, use the line. What happened here, and why?" She talks it through from left to right, mostly correctly, and the class supplies what she misses.
How you’ll know it’s working
- The board starts empty and fills as the explanation proceeds, with each new mark arriving alongside the sentence that explains it.
- Pens stay down during the build, and students' eyes follow the pen rather than their exercise books.
- When students explain the idea back, they point to the diagram or trace its shape in the air, and their answers follow its order.
- At the closing redraw, around four in five students can reproduce the diagram and its labels from memory.
Pitfalls & fixes
- Decorating the slide instead of drawing the idea. Clip-art and background photos sit beside an explanation without carrying any of it, and they tend to pull attention away from the words. Ask of every mark which part of the idea it shows, and cut any mark that has no answer.
- Letting the diagram outgrow the idea. Detail creeps in until the visual needs an explanation of its own. Keep to one idea per drawing, and start a fresh drawing for the next idea.
- Words and pen out of step. Drawing step three while talking about step four splits attention, and both channels suffer. Keep them matched moment to moment, and pause your talking while you finish a fiddly mark.
- Students copying during the build. Half the room draws your last mark while you explain the next one, and hears little of the explanation. Keep pens down during the build; the redraw at the end is their time to draw.
Weigh it up
Why it’s worth it
- More of a difficult explanation lands. The words and the image share the load, and a student who loses the thread of the words can rejoin through the picture.
- Abstract ideas gain a shape students can point at. Change over time becomes a line and a process becomes a chain of boxes, giving students something concrete to attach the words to.
- Watching a drawing appear helps hold attention during teaching from the front. The pen is always doing something, and eyes tend to follow it.
- The closing redraw doubles as a check for understanding. Thirty redrawn diagrams can show you within minutes which part of the explanation failed to land.
- The topic gains a second route back at revision time. Students who can recall the diagram usually find that the words return with it, and redrawing it from memory is retrieval practice in itself.
The costs
- The design work is real. Some ideas resist a simple shape, and finding an honest one can take longer than planning the rest of the explanation.
- Live drawing is slower than showing a slide, and your first attempts are likely to wobble while you learn to talk and draw at the same time.
- A wrong shape sticks as firmly as a right one. Draw a timeline for something that is not really a sequence and students are likely to remember the sequence anyway.
Adaptations
- Early years / lower primary: pairing pictures with words is already the norm here. What the technique adds is building the picture in front of the children and asking them to read it back to you.
- Secondary essay subjects: draw the argument. An essay plan works well as labelled boxes joined by arrows, and change across a novel or a period works as a line with the turning points marked.
- Maths and science: these subjects are full of diagrams already, so the change is smaller. Draw them live while narrating each mark, and keep the first version simpler than the textbook's finished figure.
- Post-16 / adult: show the method openly and hand it over. Students who sketch ideas from memory while revising gain the same benefit working alone, and it is a stronger habit than re-reading notes.
Where this comes from
The underlying idea is Allan Paivio's dual-coding theory: verbal and visual information are held in partly separate systems that can support each other. Richard Mayer's multimedia-learning research provides the classroom-relevant findings, showing that people learn more when words and relevant pictures are combined, kept simple and presented together. Oliver Caviglioli popularised the approach for teachers in Dual Coding With Teachers, and the Learning Scientists include it in their six strategies for effective learning. The live-drawn format itself is teacher craft; most of the research tested prepared multimedia lessons rather than a teacher drawing at a board.
Sources
Related techniques
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