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.

The split-attention principle states that when designing instruction, including multimedia instruction, it is important to avoid materials that require learners to split their attention between multiple sources of information. Instead, materials should be formatted so that disparate sources of information are physically and temporally integrated, thus obviating the need for learners to engage in mental integration. By eliminating the need to mentally integrate multiple sources of information, extraneous cognitive load is reduced, freeing resources for learning (germane cognitive load). This chapter provides the theoretical rationale, based on cognitive load theory, for the split-attention principle, and describes the major experiments that establish the validity of the principle, identifies the conditions under which it is most likely to occur, and indicates the instructional design implications when dealing with multimedia materials.