Redundancy principle
Students learn better from animation with descriptive audio than from animation, descriptive audio and onscreen text.
Sometimes, text is added to the graphic elements on-screen and simultaneously, the audio repeats the written text. The learning effect seems to be smaller here. Add no text to an audio- guided graphic element, otherwise you overload the visual channel of the working memory and the student will pay too much attention to the text and thus give less attention to the associated graphic element.
Special cases in which you are considering adding on-screen text to audio:
- If there are no graphics supportting the text.
- If the onscreen text and the associated graphic elements are to appear in a sufficiently slow waysuccessively.
- If the student needs to make much more effort to understand the spoken text (eg. For students who do not follow the course in their native language, in case of difficult and long audiofragments or audio with new keywords).
- If only a few key words appear next to the graphic element.
- When it comes to learning a foreign language.