Multiple Species of Distinctiveness in Memory: Separating Task Distinctiveness from Statistical Distinctiveness
Matthew R. Gretz · Aquila Digital Community (University of Southern Mississippi) · 2019
Distinctiveness refers to the memorial benefit of processing unique or item-specific features of a memory set relative to a non-distinctive control. Traditional distinctiveness effects are accounted for based on qualitative differences in how distinctive items are encoded at the time of study. This thesis project aims to evaluate whether a different species of distinctiveness—statistical distinctiveness—may provide a separate contribution to memory beyond traditional encoding-based processes. Statistical distinctiveness refers to the relative frequency with which a specific memory item or set is processed. The current study evaluated statistical distinctiveness through a series of mixed groups in which DRM lists were studied using two of the following three tasks to promote either shallow (“E” identification), neutral (reading silently), or deep/distinctive (pleasantness ratings) levels-of-processing followed by a final recognition test. Participants studied lists in which these tasks were used frequently (80% of lists), equally (50% of lists), or infrequently (20% of lists) which were further compared to a set of pure groups in which all lists were studied using a single task. No recognition advantage was found when tasks were completed infrequently versus frequently. Rather, recognition was greatest for the deep/distinctive task—a pattern consistent with encoding but not statistical distinctiveness.