Multimedia instructions and Cognitive Load Theory: split-attention and modality effects

Despite the huge production of all sorts of multimedia instructions, educational research has yielded surprisingly few general design principles for instructions in which verbal and visual information are combined. Instructional designers seem to base their design choices more on intuitive ideas than on sound research results. There are however some interesting theories that give guidelines for instructional designers. Mayer (1997) describes in his Generative Theory of Multimedia Learning how the learner builds mental representations of multimedia material. One important step in this process is the integration of both visual and verbal information. Multimedia instruction in its most elementary form consists of a picture with an explanatory text. Because picture and text cannot be perceived simultaneously, the learner is forced to switch back and forth between the two and integrate them mentally. According to Cognitive Load Theory (Sweller, 1988; Sweller, van Merriënboer & Paas, 1998) this integration process is cognitively demanding and at the expense of mental resources that could otherwise be allocated to the learning process. Sweller et al. call the unnecessary cognitive load caused by the presentation format of instructions extraneous load. A design guideline that follows from Cognitive Load Theory is to keep the extraneous load of instructions as low as possible, so that the available mental resources can be used for the actual learning process. In their empirical research, Sweller and his co-workers have demonstrated a number of ways in which the extraneous load of instructions can be influenced. In our study we compared two ways of lowering the extraneous load of multimedia instructions, preventing split-attention and presenting text as audio, in order to find out which one is more effective.