In multimedia presentations that consist of both verbal explanations along with visuals like animations and still frames, is there a significance in the way words are presented? Would there be a difference if words were presented as on-screen text compared to spoken text?
Mayer and his colleagues have emphasized over and over the significance of presenting modules and information in ways that are consistent with how the human mind works. Among the many principles described in his work, the Modality Principle has the most number of studies and scientific evidence to support it.
This principle holds that words, when presented together with other visuals, should be presented as speech rather than on-screen text. Narration has been found to be more effective that on-screen text when presentations heavily involve both visuals and verbal information.
Many modules, when teaching a learner about a process or mechanism, can present graphics with corresponding on-screen text explanations that may be quite lengthy. The problem with this is that it contradicts the way people absorb information from the environment. The cognitive theory of learning shows that there are two different channels used when people process information – the visual channel and the auditory channel. We use the auditory channel when we absorb information in the form of words, referred to as verbal information. In learning, when verbal information is presented as text together with visual stimuli, these two forms compete for the same limited capacity of the visual channel.
When words are presented as on-screen text along with pictures or animations, there is an increased chance for overloading of the visual channel. The learner has to pay attention to graphics, at the same time, process information from printed words. This presents a problem to learning, since it becomes difficult to give equal attention to both the graphics and the text, especially if the graphic is complex or the presentation is fast-paced. To address this problem, the modality principle suggests that the demands on the visual processing channel should be reduced to minimize overloading and prevent inefficient learning.
When words are presented as speech, verbal information enters the brain through the ears into the auditory channel, while graphics are simultaneously processed via the eyes in the visual channel. This prevents overloading of any one channel, and allows words and pictures to be processed at the same time.
The modality channel excellently explains how to make efficient use of both channels. Yet as with all aspects, there are certain limitations to it. Some instances where this principle is not applicable are the following:
- When the learning environment cannot cater to the required technical demands to deliver auditory information, like providing headsets, sound card or meeting the allowable bandwidth
- When spoken words may create undesirable noise in the learning setting
- When adding spoken narrations require expenses that are beyond the means of the organization
- When information is required to be frequently updated
Additionally, when the narration involves words that are highly technical, unfamiliar, or difficult to understand, additional on-screen text may be used for easier recall. This is also applicable when discussing complex formulas or mathematical problems, where the formula has to be found on-screen for easy access.
Overall, the modality principle should only be applied in instances where words are used simultaneously with graphics, and is not applicable when words alone are used, as this as this does not interfere with any other visuals.