When planning for a class, one question to answer is “How many separate techniques should I present in a class?” How much information can you present to a class before the students become overloaded and start forgetting what you presented?
One way to determine this limit is to use the principle of chunking. Chunking pertains to the number of units of information that students may effectively process during one class. The principle was first put forward in 1956 by Harvard psychologist George Miller in his classic article The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information (The Psychological Review, 1956, vol. 63). The principle applies to all types of communication but it is particularly useful in written communication.
Miller studied short-term memory. For example, how many numbers may people be reliably expected to remember a few minutes after having been told these numbers only once. He determined the number to be "The Magical Number Seven, Plus or Minus Two." Miller concluded that people could reliably be expected to remember five to nine things at once and that the exact number will depend on the complexity of the information; the more complex the information the less of it people may remember. For example, when teaching a new pattern to students, only about seven steps should be taught in a class, few more if the steps are simple, a few less if the steps are complicated.
Chunking is the breaking down of information into useable chucks. If the information is complex, it may be broken into chucks of 5 to 9 major points and then only one chuck is presented during each class. If the information is relatively simple, 5 to 9 major points of the information may be presented during each class.
When you notice students are not retaining what you have taught them during a class, it may be because you are teaching too many things during each class. By using chunks, you will be a more effective instructor.