The presentation of material to the learner with the subsequent task of recalling as much as possible about the material without any cues.
A typical experiment involving the use of words as stimuli may include unrelated or related words, single or multiple presentations of the words, and single or multiple tests involving memory. In a free-recall test, the learner organizes the information by memory, and the process of recall often reveals the mental processes that the learner uses. For example, words positioned at the beginning and the end of a list are most likely to be remembered, a phenomenon called the serial position effect. Further, any unusual stimuli have a greater chance of being recalled, a phenomenon called the von Restorff effect.
Learners tend to organize related material in ways that enhance recall. One process, clustering, involves placing words that are associated with one another in one "location" in memory. The advantage of clustering is that recall is easier because the person can search one mental "location" and find several stimuli. The disadvantage of this strategy is that people may erroneously think that certain stimuli occurred because they are associated with the clustered items. Such falsely remembered words are referred to as intrusions.
As a rule, an individual can remember an average of about seven stimuli in a typical free recall task. This generally translates into a total of five to nine items. Psychologists refer to the "magic number seven, plus or minus two," as the amount that people can remember without engaging in rehearsal or other memory-enhancing tactics. Researchers have discovered that people can recall about seven items, but the "items" are not limited to words. If given a list of book titles, for example, a learner might be able to recall about seven titles, even though each title consists of multiple words. The critical element is the number of meaningful units, not simply the number of words. If the learners have to recall the stimuli in the same order in which they were presented, the results are less successful than if the learners can retrieve the stimuli in their own preferred order.