The role of visual indicators in dual sensory mode instruction
Advances in our knowledge of the structure of working memory suggest that under some circumstances, effectively more processing capacity is available to learners if instructional materials use multiple information modes (e.g. auditory and visual) instead of equivalent single mode formats. This paper examined this modality effect from a cognitive load perspective in three experiments using geometry instruction. In accordance with cognitive load theory, it was predicted that the additional processing capacity provided in an audio/visual format would only enhance learning if mental resources were not devoted to extensive visual based search in order to coordinate auditory and visual information. Using two different areas of geometry, Experiments 1 and 2 found that if visual search was clearly high, then audio-visual instruction was only beneficial if visual indicators in the form of electronic flashing were incorporated into the instructional format. Under high search conditions, a standard audio/visual format without the aid of flashing proved no better than visual only instruction. Experiment 3 attempted to clarify earlier results by using instructional materials trivially low in visual search. Data indicated that a standard, audio-visual format resulted in superior learning to a visual only format. There was no beneficial effect of electronic flashing in Experiment 3, suggesting that visual indicators were not necessary in areas of low visual search. It was concluded that cognitive load as determined by visual search established the effectiveness of visual indicators.