Roxana Moreno and Richard E. Mayer
U niversity of California, Santa Barbara
Santa Barbara, CA 93106
Abstract. H ow should we design visual presentations to explain how a complex system works? One promising approach involves multimedia presentation of explanations in visual and verbal formats, such as presenting a computer-generated animation synchronized with narration or on-screen text. In a review of three studies, we found evidence that presenting a verbal explanation of how a system works with an animation does not insure that students will understand the explanation unless research-based cognitive principles are applied to the design. The first two studies revealed a split -attention effect, in which students learned better when the instructional material did not require them to split their attention between multiple visual sources of information. The third study, 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 two cognitive principles of multimedia learning.
The purpose of this paper is to propose a set of instructional design principles for visual presentations, as derived from a review of recent empirical studies on multimedia learning. In all studies, students were presented with verbal and non-verbal visual information and their learning from the multimedia lesson was compared to that of students who were presented with identical graphics and animations but instead of viewing on-screen text, listened to a narration.
In defining multimedia learning it is useful to distinguish among media, mode and modality. Media refers to the system used to present instruction, such as a book-based medium or a computer. Mode refers to the format used to represent the lesson, such as words versus pictures. Modality refers to the information processing channel used by the learner to process the information, such as auditory versus visual . Of particular interest for the present review is the study of how specific combinations of modes and modalities may affect students' learning of scientific explanations, such as when we combine visualverbal material (i.e., text) or auditory-verbal material (i.e., narration) with visual-non-verbal materials (i.e., graphics, video or animations).
In all studies, after viewing a multimedia presentation, students had to complete a series of tests aimed to assess their retention and learning. Participants were asked to write down as much of the material as they could remember (retention test), to give names for parts of the animation (matching test), and to apply what they have learned to solve new problems (transfer test). Based on the results of our studies, two design principles will be proposed: the split-attention principle, and the modality principle. 1.1 Issue 1: A Split-Attention Effect
How should verbal information be presented to students to enhance learning from animations: auditorily as speech or visually as on-screen text? In order to answer this question, Mayer and Moreno  asked students to view an animation depicting a complex system (the process of lightning formation, or how a car's braking system works), either along with concurrent narration (Group AN) or along with concurrent onscreen text (Group AT). Our goal was to test a dual-processing theory of multimedia learning based on the following assumptions: (a) working memory includes an auditory working memory and a visual working memory,
analogous to the phonological loop and visuo-spatial sketch pad, respectively, in Baddeley's [1, 2] theory of working memory; (b) each working memory store has a limited capacity, consistent with Sweller's [3, 12, 13] cognitive load theory; (c) meaningful learning occurs when a...