Principle 1:
The 'Dual-Channel Assumption' can be successfully used to effectively manage cognitive load and improve learning outcomes in multimedia learning systems.
The 'dual-channel assumption' (Paivio, 1986; Baddeley, 1998) posits that there are two cognitive channels used when processing multimedia information: visual and verbal. Each channel extends from sensory memory through into working memory, and each has limited capacity (Chandler & Sweller, 1991; Sweller, 1999; Baddeley, 1998). Designing a multimedia system to share the load across these two channels (instead of all information passing through one channel) leads to an increase in germane cognitive load (Wittrock, 1989; Mayer, 1999, 2002) and a decrease in instrinsic and extraneous cognitive load, making better use of working memory capacity. Note that
Principle 2:
Narration is superior to written text when language is presented as part of the animation.
All animation necessarily is received and processed in working memory via the visual channel. While text is also received via the visual channel, narration is received via the verbal channel. When an animation is accompanied by text as an adjunct to the instruction, the visual channel can be overloaded easily. By using narration instead of text, the verbal channel is used instead, leaving the visual channel devoted entirely to the animation, reducing potential for intrinsic cognitive overload. (Mayer & Moreno, 2003)
References:
Baddeley, A. (1998). Human memory. Boston: Allyn & Bacon.
Chandler, P., & Sweller, J. (1991). Cognitive load theory and the format of instruction. Cognition and Instruction, 8, 293-332.
Mayer, R. E. (1999). The promise of educational psychology: Vol. 1, Learning in the content areas. Upper Saddle River, NJ: Prentice Hall.
Mayer, R. E. (2002). The promise of educational psychology: Vol. 2, Teaching for meaningful learning. Upper Saddle River, NJ: Prentice Hall.
Mayer, R. E., & Moreno, R. (2003). Nine ways to reduce cognitive load in multimedia learning. Educational Psychologist, 38(1), 43-52.
Paivio, A. (1986). Mental representations: A dual coding approach. Oxford, england: Oxford University Press.
Sweller, J. (1999). Instructional design in the technical areas. Camberwell, Australia: ACER Press.
Wittrock, M. C. (1989). Generative processes of comprehension. Educational Psychologist, 24, 345-376.