The precise time course of retention

Fits of retention data were examined from 5 conditions: 3 types of cued recall, an old-new recognition task, and a remember-know recognition task. In each condition, 100 participants had either 18 recall or 27 recognition trials at each of 10 delays between 0 and 99 intervening items, providing the first data obtained in experimental psychology that were precise enough to distinguish clearly among simple functions. None of the 105 2-parameter functions tested produced adequate fits to the data. The function y = a(1)e(-t/1.15) + a(2)e(-t/T2) + a(3) fit each of the 5 retention conditions. The T-2 parameter in this equation equaled 28 for the 3 recall conditions and the remember-know recognition condition and 13 for the old-new recognition condition. Individuals' recall data fit the same function with parameters varying with gender and scholastic aptitude scores. Reaction times support the claim that the a(l)e(-t/1.15) term describes working memory, and the remaining 2 terms describe long-term memory.