PULLMAN, Wash.— Which students learn the most: those who hear a presentation, those who read it, or those who both hear and read the words?
Olusola Adesope, an assistant professor in the Washington State University College of Education, reviewed 1,857 studies to come up with an answer. He took a close look at 57 of them.
“Overall, there was no difference between those who both listened to and read a lesson and those who only read it,” said Adesope. “But both of those groups outperformed those who only heard the lesson.”
Adesope was given the 2011 G.M. Dunlop Award by the Canadian Association for Educational Psychology for the paper he wrote on his research.  An extended version of the paper, “The Cognitive Effects of Verbal Redundancy on Learning,” is under review for publication in a top international journal.
Adesope found that a combination of spoken and written lessons was especially helpful if the visual material contained key phrases from the spoken lesson, or if the students had visual, hearing or learning disabilities.
Such lessons include books accompanied by audio or television programs with closed captions, though most of the studies Adesope reviewed involved computer-based lessons. He emphasized that they were not intelligent tutoring systems—that is, they didn’t provide feedback, as do interactive programs and classroom instructors.
That said, Adesope advises against using written text to explain diagrams or other illustrations. For example, a biology professor who shows an animation of how a cell functions should talk about what students are seeing, but not also show explanatory text.
“Our brains are designed to take in visual and auditory messages at the same time, but they’re not good at absorbing two visual messages at once,” he said.
Adesope earned his Ph.D. in 2010 from Simon Fraser University in British Columbia.