ARE YOU THINKING ABOUT USING ONSCREEN TEXT and identical audio narration to describe pictorial information for a multimedia presentation? Think again. Combining printed words with identical, simultaneous audio narration to describe onscreen graphics--animation, video or even static pictorial information--has proven to stifle the learning process by overloading the learner's visual channel. (Clark & Mayer, 2004)

The use of redundant onscreen text (redundant text) grew out of the belief held by many multimedia learning developers that people are either visual learners or auditory learners. In order to accommodate both learning styles, developers began to combine redundant text with identical audio narration to describe onscreen graphics.

While learners engaged in multimedia instruction do utilize two channels for processing information (pictorial and verbal), these channels maintain a limited capacity that can be overloaded quite easily when faced with excessive information such as redundant text. The Redundancy Principle was developed by Clark & Mayer to help elearning designers understand the adverse effects of using duplicate onscreen text on the learning process.

Press "Play" to see a demonstration of redundant onscreen text.

Where did your eyes focus during the narration?

According to Clark & Mayer's cognitive theory of multimedia processing, learners engaged in multimedia instruction process more efficiently when there is a balanced, optimal flow of information through the visual and auditory channels.

Balanced flow of information.

As the presented material flows optimally into working memory through the visual and auditory channels, the learner's natural cognitive processing abilities begin to build verbal and pictorial mental models. The learner then uses these mental models to form the conceptual connections intended by the material.

Verbal and pictorial mental

models are developed.

By including redundant text in a multimedia presentation, visual focus is split as the learner is forced to process multiple pieces of information through the visual channel. This split focus not only overloads the visual component of working memory but hinders the learner's ability to process the information efficiently, build appropriate mental models and ultimately make the conceptual connections intended by the instructional media.

Split focus overloads the
visual channel of working memory.

There are a few instructional circumstances where using redundant text is acceptable and even suggested. Use redundant text...

• When there is a complete absence of any onscreen pictorial information.
• When the learner has plenty of time to process the multimedia elements (text and graphics) or when the information is presented sequentially.
• When the relative linguistic complexity of the audio might be difficult for the learner to understand--as with foreign language learning or certain auditory learning disabilities.

In these situations, redundant text provides a supplemental, and in some cases necessary, learning mode.

Matt McNerney
Graduate Student
Department of Educational Technology
San Diego State University