Design Dilemma: Your school principal has asked you to explain why you don’t include text to match your narration of multimedia instruction. (S)he cites different learning preferences as being the reason, along with adding additional modalities to improve learning. How would you answer?
Assuming that the multimedia instruction has graphics that are significant to the presentation, text should not be included because it will serve as a distraction. The reason being that when you have a significant of amount textual information in the presence of graphics, it creates a cognitive overload on the visual channel because the eyes must decipher two sets of information. By applying modality principle 1, learning will be more effective when splitting the information processing into two channels – one for the audio and the other visual.
The principle may still insist on having on-screen text that matches the narration. I would explain that this violates that the redundancy principle, which states that redundant material is not effective for learning because on-screen text with a graphic will overload the visual channel. Sometimes there are exceptions and you will find on-screen texts with narration. This could be when there are non-native language speakers, complicated technical terms, or when learners control the pace of the presentation. If the presentation really required both spoken and written text, I would recommend using only few key words to outline the main points or eliminate the graphic all together. However, if the graphic is essential to the presentation, having a narration with the screen text followed by the graphic with the key points summarizing the previous description could be a possible option. This process of splitting the presentation would not overload the visual channel and when organized in this manner, previous studies showed that the redundant group out-performed the non-redundant group.