However, double mode will also cause a redundancy effect. Diao and Sweller (2007) conducted a study with university students which demonstrated that text-only presentation mode was better than synchronised sound and text presentation mode, for both performance and cognitive load. This result supported the proposition that the redundancy effect occurs when sound is presented simultaneously with text, which is not beneficial to learning. However, this study did not take learners’ prior knowledge into account. A Chinese learning study, with high school.
