Multimedia messages should be designed to facilitate multimedia learning processes. This chapter first explores three assumptions underlying a cognitive theory of multimedia learning: dual-channel assumption, limited-capacity assumption and active processing assumption. Three memory stores in the cognitive theory of multimedia learning are: sensory memory, working memory, long-term memory. For meaningful learning to occur in a multimedia environment, the learner must engage in five cognitive processes: selecting relevant words for processing in verbal working memory, selecting relevant images for processing in visual working memory, organizing selected words into a verbal model, organizing selected images into a pictorial model, and integrating the verbal and pictorial representations with each other and with relevant prior knowledge activated from long-term memory. The chapter also explores three demands on cognitive capacity during multimedia learning: extraneous processing, essential processing and generative processing.

Extraneous overload occurs when essential cognitive processing (required to understand the essential material in a multimedia message) and extraneous cognitive processing (required to process extraneous material or to overcome confusing layout in a multimedia message) exceed the learner's cognitive capacity. According to the cognitive theory of multimedia learning, the five ways to handle an extraneous overload situation are to: eliminate extraneous material (coherence principle), insert signals emphasizing the essential material (signaling principle), eliminate redundant printed text (redundancy principle), place printed text next to corresponding parts of graphics (spatial contiguity principle), and eliminate the need to hold essential material in working memory for long periods of time (temporal contiguity principle). The research reviewed in this chapter shows that instructional designers should be sensitive to the limitations of working memory by being careful about the amount and layout of information that is presented to learners.