Cognitive load theory is an instructional theory based on our knowledge of human cognitive architecture. Instructional design that does not take human cognitive architecture into account is likely to be random in its effectiveness. The theory assumes that one has a limited working memory to process novel information and a large long-term memory used to store knowledge acquired for subsequent use.
The purpose of instruction is to store information in long-term memory. That information consists of everything that has been learned, from isolated facts learned through memorization to complex, fully understood concepts and procedures. If nothing has changed in long-term memory, nothing has been learned.
Cognitive load theory has been used to generate a wide range of instructional procedures, some of which are summarized here. Each of the effects is concerned with procedures for reducing extraneous working memory load to facilitate knowledge acquisition in long-term memory.
The worked example effect
Many studies have demonstrated that studying worked examples is superior to solving the equivalent problems. This effect helps us conclude that instruction should be explicit and complete. Withholding information from students based on a constructivist teaching regime is likely to be ineffective.
The split-attention effect
This effect occurs when physically integrated information presented to learners is superior to information requiring them to split their attention between multiple sources of information. For example, if a diagram and text are unintelligible in isolation and must be mentally integrated, it is better to place the text on the diagram rather than as a block next to it.
The modality effect
A similar effect may be obtained by presenting the text in spoken rather than written form because using both the visual and auditory working memory processors increases working memory capacity.
The redundancy effect
The split-attention and modality effects are only obtainable when multiple sources of information are unintelligible in isolation. If, for example, textual information merely repeats diagrammatic information, it is redundant and should be eliminated rather than integrated with the diagram or presented in auditory form. Improved performance following the elimination of repeated information provides an example of the redundancy effect.
The expertise reversal effect
All previously mentioned cognitive load effects are only obtainable with complex information, and often disappear with simpler information. Similarly, these effects are only obtainable using novice learners in an area. As levels of expertise increase, the effects are reduced and eventually disappear. With increasing expertise they reappear, but in reverse.
There are many other cognitive load effects. A summary may be found in the resource below:
Clark, Ruth C., et al.
Efficiency in Learning: Evidence-Based Guidelines to Manage Cognitive Load.
San Francisco: Pfeiffer, 2006