Eighty percent of learners are visual learners. That means they take in information, and process it better, using their eyes rather than their ears.  While this is a long-standing known fact, very few trainers create training materials that are visually appealing. Visuals don't only appeal to our senses they also appeal to our ability to learn.

In a study conducted by two professors from the University of California, Santa Barbara titled: A Cognitive Theory of Multimedia Learning: Implications for Design Principles, they speak of the principle of Multiple Representation. In short, the principle states that it is better to present an explanation in words and pictures than solely in words. When a learner sees both words and pictures, he's able to build two different mental representations-a verbal model and a visual model-and then build connections between them.

They also noted that a learner is better able to understand an explanation when the words and pictures are presented at the same time rather than when they are separated in time. This is known as Contiguity Effect - corresponding words and pictures must be in working memory at the same time in order to facilitate the construction of referential links between them.

An interesting corollary to their research is that they discovered that words should be presented verbally rather than visually. This is more related to online learning than classroom-based training;  they discovered that on-screen text and animation can overload the visual information processing system, whereas narration is processed in the verbal information processing system and animation is processed in the visual information processing system.