A role for familiarity in supporting the testing effect over time

Endel Tulving (1985) drew a distinction between Remembering and Knowing, spurring a great deal of research on the memorial experiences of recollection and familiarity and their contribution to various phenomena in memory. More recently, studies have used this distinction to situate our understanding of the processes that contribute to the testing effect-or, the benefit of retrieval practice to later memory (see also Tulving, 1967). Using retention intervals of approximately 15 min or less between initial and final testing, several studies have found that initial testing magnifies estimates of recollection but not familiarity, regardless of whether a testing effect is revealed in overall recognition performance (Chan and McDermott, 2007). However, the efficacy of prior testing in enhancing memory has been shown to change over time, as have estimates of recollection and familiarity. Thus, the mechanisms that underlie the quintessential testing effect-one that occurs in overall recognition or recall over longer delays-are still uncertain. To investigate this issue, in two experiments, subjects studied word lists, took 3-letter stem cued-recall tests on half of the studied words, and completed a final recognition test in which estimates of recollection and familiarity were obtained via confidence (Experiment 1) or Remember-Know-New (Experiment 2) judgments. Critically, final recognition tests occurred either immediately, 1 day (Experiment 1 only), or 4 days after initial learning. At all retention intervals and in both methods of estimating recollection and familiarity on the final test (i.e. receiver-operating characteristic and remember-know analyses), initial testing magnified estimates of both recollection and familiarity. These findings suggest that the testing effect can result from changes in both processes and pose issues for theories of the testing effect that consider an exclusive role for recollection.