Many of us know intuitively that having lots of bullet-points on our slides isn’t effective. But it’s useful to have some scientific evidence to back up that intuition. New research on multitasking may provide that.
In the research carried out at the University of Michigan and reported on the NPR website, subjects were asked to perform different tasks while lying in an MRI scanner. The research shows that multitasking is a human delusion. In fact we switch rapidly from one task to another. One of the reasons for this is that similar tasks compete for use of the brain. Neuroscientist Earl Miller at the University of Michigan said:
Think about writing an e-mail and talking on the phone at the same time. Those things are nearly impossible to do at the same time. You cannot focus on one while doing the other. That’s because of what’s called interference between the two tasks. They both involve communicating via speech or the written word, and so there’s a lot of conflict between the two of them.
Applying this to PowerPoint presentations, reading bullet-points and listening to the presenter are conflicting tasks. If a person in your audience is reading a bullet-point they are not listening to you.
So what does this mean for the use of text on PowerPoint slides? Should we use any text at all? I think short pieces of text can have a place on PowerPoint slides. It’s hard work listening to a monologue – we’re much better at listening when it’s a dialogue and we’re expecting to take our turn at speaking. So as speakers we need to help our audiences to stay tuned in. You can so this by by isolating your main point for each part of your presentation and putting it on a slide. The text will act as an anchor in three ways:
- It will help emphasise that this an important point.
- It will provide a visual memory of the point particularly if teamed with an arresting image.
- It will provide longevity to your words.
- And lastly, should someone tune out temporarily, when they tune back in they’ll know what you’re talking about.
But keep it short. My rule of thumb is one short sentence which expresses the point of the slide.
And stop talking when you first show the slide. It doesn’t take long for people to read one short sentence – maybe 2-3 seconds. Keep silent for that time and they won’t have a conflict between reading and listening to you.