Retention of Spanish vocabulary over 8 years.

Thirty-five individuals who had learned and relearaed 50 English-Spanish word pairs were tested for recall and recognition after an interval of 8 years. Two variables, the spacing between successive releaming sessions and the number of presentations required to encode individual word pairs, are excellent predictors of the likelihood of achieving permastore retention. Optimum recall occurs for words encoded in 1 -2 presentations and accessed at intervals of 30 days. Both variables yield monotonic retention functions that account for a range of variation from 0% to 23% recall. These variables also have very significant effects on the recognition of unrecalled words. A recent investigation of the retention of Spanish language learned in school (Bahrick, 1984) shows that a portion of the acquired knowledge has a life span of more than 25 years even if the knowledge is not rehearsed or accessed during that long interval. Another part of the originally acquired knowledge is lost within 5 years after training terminates, and virtually no knowledge is lost during the interval between 5 and 25 years following acquisition. This finding suggests the challenging possibilities of identifying conditions of learning and/or characteristics of material associated with a prospective life span of more than 25 years and of differentiating these conditions and characteristics from those associated with material destined to have a relatively short life span (less than 5 years). Such information would augment the very limited knowledge of life span memory currently available and make memory research more relevant to the needs of educators who have an obvious interest in prolonging the life span of transmitted knowledge. However, the research is arduous because it requires longitudinal investigations to extend substantially beyond the 5-year period during which material with a short life span is likely to be forgotten. The foregoing considerations led us to search for relevant longitudinal data, and we realized that such data might be available to us if we conducted a follow-up to an earlier investigation (Bahrick, 1979). The aim of the earlier investigation was to establish the effect of various rehearsal schedules on maintaining access to learned material over periods of 1 -9 months. One part of that investigation required college students to learn and relearn 50 English-Spanish word pairs in successive training sessions, spaced at intervals varying from a few seconds