When less is more: Meaningful learning from visual and verbal summaries of science textbook lessons.

In a series of 3 experiments, college students who read a summary that contained a sequence of short captions with simple illustrations depicting the main steps in the process of lightning recalled these steps and solved transfer problems as well as or better than students who received the full text along with the summary or the full text alone. In Experiment 2, taking away the illustrations or the captions eliminated the effectiveness of the summary. In Experiment 3, adding text to the summary reduced its effectiveness. Implications for a cognitive theory of multimedia learning are discussed; implications for instructional design pertain to the need for conciseness, coherence, and coordination in presenting scientific explanations. Consider the following scenario. A student who is inexperienced in meteorology reads a textbook lesson explaining the cause-and-effect chain of events involved in how lightning storms develop. The explanation is clearly contained within the 600 words and five illustrations of the lesson. A few minutes later, we ask the student to write down the explanation (as a retention test) and to solve some problems that require using the explanation from the lesson (as a transfer test). For example, as a transfer problem, we ask the student to write an explanation for why there can be clouds in the sky but no lightning. Despite exerting considerable effort, the student performs poorly on both the retention and the transfer task, indicating a lack of understanding of the process of lightning.