When a multimedia lesson containing complicated material is presented at a fast pace, the result can be a form of cognitive overload called essential overload. Three multimedia design methods intended to minimize essential overload are the segmenting, pre-training, and modality principles. The segmenting principle is that people learn more deeply when a multimedia message is presented in learner-paced segments rather than as a continuous unit. The pre-training principle is that people learn more deeply from a multimedia message when they know the names and characteristics of the main concepts. The modality principle is that people learn more deeply from a multimedia message when the words are spoken rather than printed.

Multimedia learning is learning from words and pictures. The rationale for studying multimedia learning is that people can learn more deeply from words and pictures than from words alone. A goal of research on multimedia learning is to understand how to design multimedia learning environments that promote meaningful learning. The research base concerning multimedia learning is reflected in the 46 chapters of this Handbook, and includes 30 design principles that we have organized into three categories: principles based on reducing extraneous processing, principles based on managing essential processing, and principles based on fostering generative processing.