Clouse (1969) found that the type of cue given had more effect on acquisition and retention than the number of cues. Guthrie (1967) stated that instruction containing rules improved the speed of learning and the retention of material. One writer has suggested that the acquired knowledge is stored in the memory in deep-structure language units (Rohrman, 1968). Two other writers have hypothesized that information is not stored as words at all, but as nonverbal, cognitive representations (Rosenfield, 1968; Johnson, 1968). Once the material has been learned, individual differences in retention are apparently slight (Shuell & Keppel, 1970).
Several factors are influential in the acquisition and retention of knowledge: subsumption, intent to learn, type of material, organization of material, and appropriateness of material. Ausubel and Fitzgerald (1961), in support of AusubePs theory of subsumption of acquired knowledge into the learner's existing cognitive structure, reported that students who were familiar with Christianity learned more and retained more information after having studied Buddhism. Klausmeier and Ripple (1971, p. 610) quote the results of several studies related to retention and recall. Intent to learn has been found to be an important variable in the acquisition and retention of material. Another factor is the type of material being learned. Ideas are retained much longer and more completely than facts, while facts are retained longer and more completely than nonsense syllables (p. 599). The organization of the material facilitates initial learning and promotes retention (p. 591). Another crucial variable seems to be the appropriateness of the material for each student's level of achievement. Content that is beyond the student's capability is inadequately learned and therefore imperfectly retained (pp. 611-12).
Underwood has divided memory into various types of attributes. The first category includes those attributes independent of the learning task:
1. Temporal attribute, remembering the time something happened.
2. Spatial attribute, remembering where something was located.
3. Frequency attribute, remembering the number of times something occurs.
4. Modality attribute, remembering something through auditory or visual recollection of experience.
The second category consists of those attributes dependent upon the task:
1. Acoustic attribute, remembering something on the basis of its sound.
2. Visual attribute, remembering something on the basis of how it looks.
3. Affective attribute, remembering the feelings associated with some thing or event.
4. Context attribute, remembering the context in which the original learning took place.
5. Verbal attribute, remembering learned material by associating it with words or related words (Klausmeier & Ripple, 1971, 594-98).
Retrieval of learned information is another process that has been studied. The results of a study by Kiess (1968) suggested that new verbal items are incorporated into the individual's language system and that this organization according to language form facilitates the retention of these items. Gellman (1969) concluded that individuals organize material into clusters. This process of storage in clusters improves recall. In addition, evidence indicates that certain types of retrieval are superior to others. A key word often assists the individual to remember the information for which she has been searching. Gagne (1970, p. 471) notes that". . . Remembering is markedly affected by retrieval at the time of recall, more than it is, perhaps, by events taking place at the time of learning."