THE FOUR-ITEM RULE APPLIES TO MEMORY RETRIEVAL, TOO
The four-item rule applies not only to working memory, but also to long-term memory.
George Mandler (1969) showed that people could memorize information in categories
and then retrieve it from memory perfectly if there were one to three items in a category.
The number of items recalled dropped steadily when each category contained
more than three items. If there were four to six items in a category, then people could
remember 80 percent of the items. It went down from there, falling to 20 percent if there
were 80 items in the category (Figure 20.1).