Pioneered at the University of NSW, the research shows the human brain processes and retains more information if it is digested in either its verbal or written form, but not both at the same time.John Sweller, who developed the "cognitive load theory", clarifies:
It is effective to speak to a diagram, because it presents information in a different form. 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.Famed venture capitalist Guy Kawasaki has advised PowerPoint presenters to follow strict guidelines to make their presentations effective. These guidelines are primarily based on the premise that the visual aspects of a presentation should merely be cues or adjuncts to the oral component. Cognitive load theory provides a scientific rationale for Kawasaki's guidelines.