Explain Things Clearly – Dual Code

As William James famously asserts “what we attend to, we remember”. However, attention is notoriously difficult to control. Shaped by millenia of evolution, the human attention system is programmed to be captivated by both images and sounds. For our ancestors, seeing a flash of yellow might mean spotting a sabre-toothed tiger in time whilst hearing the snap of a twig nearby would turn all heads.

Our attention scans our surroundings, interprets what it hears and sees, focuses on what is important and filters out everything else. This is called dual coding and there’s a whole wealth of evidence that supports this model. Instinctively, we know it to be true – that both seeing that flash of yellow and hearing someone shout for help should complement one another. Seeing images and hearing words sharpens our attention and focus – you wouldn’t want to be the caveman for whom these things cancel one another out.

And so our attention system works on two two distinct channels, one verbal and the other visual. The channels are designed to complement one another and we can maximise on this by making sure that what we show illustrates what we say. If you describe an abstract idea in talk (e.g. quantitative easing) you might select an image that makes this concrete (e.g. a printing press churning out sheets of money) – clarity follows because the idea is dual coded.

Writing occupies a unique position – it is a visual representation (i.e. a script) of what we would ordinarily verbalise (i.e. what we would say). When we read, both parts of our attention system are at work.

We know this to be true because we have all had the experience – everybody stops listening as soon as a handout hits the table. Listeners tune you out so that they can read what you have just projected.

When you explain, exercise caution, especially regarding the written word:

  • Prioritise imagery over writing in what you choose to show.
  • Project as few written words as possible to communicate what you mean.
  • Reveal single sentences on slides, one at a time.
  • Read these for the audience so that competition for attention is minimised.
  • Hold on to your handouts!

Recommendation

If you want to become a dual-coding PowerPoint wizard, watch David JP Phillips’ Ted Talk – your slides will never be the same!