Is PowerPoint evil? The jury's still out on that. But an Australian study suggests that it is being used in the most ineffective way possible.
A study at the University of New South Wales in Australia has revealed that the common practice of showing the same words on-screen that are being spoken out loud actually makes it harder to learn and retain the information. Since the typical use of PowerPoint involves this very practice, Professor John Sweller, an education professor at the university, told the Sydney Morning Herald that "the use of the PowerPoint presentation has been a disaster."
The researchers found that the human brain processes information better when it is presented in verbal or printed form than when it is presented in both forms at the same time. So when you put up a list of bullet points on a slide and then go through them verbally, you'd be better off if your audience either ignored your slide or you.
Sweller developed his cognitive load theory in the 1980s. According to the theory, people learn best when the strain on their working memory (a collective term for the processes that temporarily store and manipulate information) is kept to a minimum. This allows them to move information from working memory into long-term memory. When cognitive load (the load on working memory) is too high, learning is more difficult.
Sweller notes that using a visual aid such as a chart is not the same kind of load, and that this is actually the best way to use PowerPoint. "It is effective to speak to a diagram, because it presents information in a different form," Sweller says. "But it is not effective to speak the same words that are written, because it is putting too much load on the mind and decreases your ability to understand what is being presented."