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VERY LONG TERM RETENTION OF KNOWLEDGE

The project examined the very long term retention of knowledge which was originally acquired from formal education and which had not been subsequently used or reviewed. In higher education a great deal of time and effort is devoted to the acquisition of knowledge, but very little is known about how long this knowledge is retained. The study was designed to supply some answers to the following questions. How much of this kind of knowledge is remembered and for how long? Are some types of knowledge better remembered than others ? Does knowledge undergo structural changes over time? Do older people forget faster than young people? Is very long term retention superior when students originally obtained high grades? Do they remember it better if they found the material very interesting when they studied it? These questions have practical relevance to educational policy and practice. They also have implications for theoretical models of memory and knowledge representation. Three different knowledge domains were investigated, cognitive psychology, experimental design and statistics, and literature. In each of these subject areas between 300-450 former students of the Open University completed a series of memory tasks designed to test retention of the course material. Approximately equal numbers of the students who were tested had studied the courses in each year between 1978 and 1989, so that the time elapsed between completing the course and the memory tests varied between 3 months and 12 years. The ages of the students at the time of testing ranged from 25 to 77 years. For cognitive psychology, the tests included recognition and recall of names, concepts, conceptual relations, general principles and specific facts. For experimental design and statistics, knowledge of principles and procedures was tested. For the literature course memory of two different classic novels was tested. The general pattern of the results showed that rapid forgetting occurs in the first two years after learning. Thereafter memory stabilized and remained at above chance levels for the remainder of the period. Knowledge which is still retained after approximately two years appears to remain intact indefinitely. There were two exceptions to this pattern of forgetting. Although memory for details and highly specific facts declined rapidly, memory for general principles was extremely stable and showed no forgetting over the 12 year period. Similarly, knowledge of experimental design and statistics also showed no significant decline over the whole of the 12 year retention period, suggesting that active use of this knowledge in practical work made it more memorable, and possibly reflecting a superior retention of procedural, as opposed to declarative, knowledge. The effects of age were slight. The elderly students had poorer memory for specific facts, but in the other tests elderly students generally remembered as well as young students. The rate of forgetting was the same for young and old, so there was no indication that elderly people forget what they have learned more quickly. Another finding of major importance concerns the extent to which good retention is associated with high grades. When grades were decomposed into examination marks and course work marks it was found that high course work marks were associated with good retention but examination marks were unrelated to retention. The findings were related to theoretical models of memory and pedagogical implications were pointed out.