Extraneous processing occurs when suboptimal instructional design causes learners to engage in cognitive processing irrelevant to the instructional goal. This chapter explores five principles for reducing extraneous processing in multimedia learning: coherence, signaling, redundancy, spatial contiguity, and temporal contiguity. The coherence principle is that people learn better when extraneous information is excluded from multimedia lessons. The signaling principle is that people learn better when cues are added to highlight the organization of the essential information. The redundancy principle is that people learn better when multimedia lessons include graphics and spoken text rather than graphics, spoken text, and printed text. The spatial contiguity principle is that people learn better when words and corresponding graphics are physically integrated rather than separated. The temporal contiguity principle is that people learn better when words and corresponding graphics are presented simultaneously rather than sequentially.

The redundancy principle (or redundancy effect) suggests that redundant material interferes with rather than facilitates learning. Redundancy is broadly defined as any unnecessary information including irrelevant information, the same information presented concurrently in multiple forms or in unnecessarily elaborated form. According to cognitive load theory, processing redundant information with essential information increases working memory load which may interfere with learning. Eliminating such redundant information removes the requirement to process unnecessary sources of information. Accordingly, instructional designs that eliminate redundant material can be superior to those that include redundancy. This chapter summarizes research and theory concerned with the effect of processing redundant information in multimedia learning, a history of research in instructional redundancy, the conditions of applicability of this principle, and its instructional implications.