Moreno, R. & Mayer, R. E. (1999). Cognitive principles of multimedia learning: The role of modality and contiguity. Journal of Educational Psychology, 91(2), 358-368.

Students viewed a computer animation depicting the process of lightning. In Experiment 1, they concurrently viewed on-screen text presented near the animation or far from the animation, or concurrently listened to a narration. In Experiment 2, they concurrently viewed on-screen text or listened to a narration, viewed on-screen text following or preceding the animation, or listened to a narration following or preceding the animation. Learning was measured by retention, transfer, and matching tests. Experiment 1 revealed a spatial-contiguity effect in which students learned better when visual and verbal materials were physically close. Both experiments revealed a modality effect in which students learned better when verbal input was presented auditorily as speech rather than visually as text. The results support 2 cognitive principles of multimedia learning.