Research Points the Finger at PowerPoint
If you have ever wondered why your eyes start glazing over as you read those dot points on the screen, as the same words are being spoken, take heart in knowing there is a scientific explanation. It is more difficult to process information if it is coming at you in the written and spoken form at the same time.
Patty, Anna. Sydney Morning Herald (2007). Articles>Presentations>Instructional Design>Microsoft PowerPoint