Monday, November 30, 2009

The Psychological Basis of PowerPoint

Whenever I visit the annual conference of the American Public Health Association, I make time to visit the vender area in order to visit all the book publishers to see what new texts have been published. This year, two texts caught my eye. One was entitled “Bioethics at the Movies” and a second was “Clear and to the Point.” Given I had limited funds with me, I ended up buying the second book (1), which is subtitled “8 Psychological Principles for Compelling PowerPoint Presentations.” This text is a fascinating explanation of how you can use insightful observations about human psychology to craft better and more effective slide presentations. The text describes how to most effectively communicate a message, looking at issues such as design, colors, legibility, graphical display and so on. But the techniques used in the book are based on just three major goals.

Goal 1: Connect with your audience. Kosslyn states that you will effectively communicate when you focus the audience’s attention on a specific message. Put another way, the goal here is not to try and pack in as much information as you can in the presentations you make. When you do, you will lose your audience quite rapidly. You should tailor your presentation to the needs of the audience, and put your material into a context that is of interest to them. For people, for example, who teach a basic science, this might mean putting your information into a context that is more clinical in nature, understanding that the reason people are in your class is not solely because they need to learn your discipline, but because their ultimate goal is to become effective practitioners and your course is a means to that end. As Kosslyn states, “You need to speak to your audience, not speak at them.” Thus, the idea is to present not too much, nor too little information. Further, your communication has to be based on prior knowledge of important concepts and jargon.

Goal 2: Direct and hold attention. You should lead the audience to pay attention to what is important in your presentation. Kosslyn makes this point: in the past, before we had PowerPoint, we used to provide our audience handouts of our lectures. Of course, what happened is that people would then simply read the handout and not pay any attention to the speaker. The corollary today is that not only might we give a handout of our slides now, we also gussy up our slides so that the audience is busy looking at everything on the slide, but are not listening to us when we speak. Since a slide show occurs over time, and because people cannot go back to read over something at their own pace, we have to present material is a way that leads the audience step-by-step to where we want them to be, but that does not lose them along the way. Thus, the slide show has to hold the audience’s attention. Kosslyn offers three tactics to help accomplish this: the principle of salience, the principle of discriminability, and the principle of perceptual organization. These refer to how we actually make sense out of words and symbols on a projected image; for further detail, see pages 7-8 of his text.

Goal 3: Promote understanding and memory. A presentation should be easy to follow and easy to remember. This is where I myself need more training, since I think my own slides do not accomplish this as well as I might like. But if you understand just a little bit about how humans process information into memory, it may help in how you craft your slide presentations. A message is easiest to understand when its form is compatible with its meaning. In a classic experiment, if you project the words “red,” “blue” or “green” first in the same color as the word, people can easily state the right color when asked, but if you use other colors (such as projecting the word “blue” in red ink) it is much harder for people to get it right all the time. Another dictum is that people can process only so much information at once, so you should work to ensure that your message does not present too much information at a given time.

These three principles drive the better part of the complete text for this excellent little book. PowerPoint is not just about using a technology to present as much information in a given period of time as possible; it is about using that technology to help process that information for later use. Applying psychological principles can help do just that.


1. Kosslyn SM. Clear and to the point: 8 psychological principles for compelling PowerPoint presentations. New York, NY; Oxford University Press, 2007

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