Understanding How Knowledge Fluctuates in Accessibility

While an impressive amount of knowledge is stored in memory, individual items can fluctuate in accessibility: Two attempts to retrieve the same knowledge (e.g., the US States) often yield somewhat inconsistent results. In this way, knowledge is unstable. The first goal of my dissertation was to document these fluctuations and to examine whether delay and testing impact this instability. Second, since knowledge is often described as being more stable relative to event memory, I directly compared fluctuations in access for the two memory types. The substantial fluctuations in knowledge documented in my first two experiments should have key implications for education, where students are regularly expected to draw upon prior knowledge. Accordingly, my third goal was to examine the power of multiple-choice testing as a tool for reactivating knowledge that has become inaccessible. In the laboratory, I compared multiple-choice testing to studying the target knowledge. My final goal was to investigate these issues in a real classroom; I evaluated the effectiveness of multiple-choice testing intervention in reactivating background course knowledge and promoting the acquisition of new material. Overall, my results highlight the instability of the knowledge base, with individual pieces of information coming in and out of reach.