On the Very Long-Term Retention of Knowledge Acquired Through Formal Education: Twelve Years of Cognitive Psychology

Former students (N = 373) of a course in cognitive psychology (CP), conducted between 1978 and 1989, completed memory tests to assess retention of CP. Memory for proper names of researchers, concepts, and conceptual relations varied with retention interval (RI), and memory performance declined over the first 36 months of retention and then stabilized at above-chance levels for the remainder of the retention period. Memory for general facts from the course and research methods did not, however, vary with RI and remained at the same above-chance level across all RIs sampled. The recall and recognition of proper names showed a more rapid decline than the recall and recognition of concepts. These findings suggest that knowledge structures formed at acquisition mediate the very long-term retention of CP. Also, Ss with higher grades retained more knowledge than Ss with lower grades. Finally, a dissociation between memory performance and confidence ratings indicates that at the longer RIs, Ss were unaware that course material was accurately remembered.