Patterns of forgetting

Abstract

Abstract In memory research, forgetting is largely assumed to occur following a relatively consistent forgetting curve. However, recent work in our lab suggests that there is a shift in the pattern of forgetting after a retention interval of about seven days. Moreover, work on narrative comprehension has shown that information at different levels of representation show different patterns of forgetting. Much of the existing work on patterns of forgetting (a) does not allow one to assess changes in forgetting because much of the data is collected either prior to or after seven days, but not sufficiently bridging this period of time, and (b) does not consider patterns of forgetting for different levels of memory representation. In this study, memory for a list of words and narrative texts was assessed up to 12 weeks after initial learning. We observed that memory for the word list showed some forgetting early on, followed by an abrupt loss after about seven days. Moreover, for the narrative text, surface form memories were forgotten to around chance level after about an hour, whereas textbase level memories were retained until about seven days when memory suddenly dropped to around chance levels, much like the word list memories. In contrast to this, memory at the event model level remained high throughout, although there was some forgetting over time. To account for this pattern of retention and forgetting, a simulation was developed as a proof of concept to illustrate our theoretical interpretation.