This item is under embargo and not available online per the author's request. For access information, please visit http://libanswers.wustl.edu/faq/5640.
Date of Award
Doctor of Philosophy (PhD)
The subsequent memory effect (SME) refers to the greater brain activation during encoding of subsequently recognized items compared to subsequently forgotten items. Previous literature regarding SME has been primarily focused on identifying the role of specific regions during encoding or factors that potentially modulate the phenomenon. The current dissertation examines the degree to which this phenomenon can be explained by item selection effects; that is, the tendency of some items to be inherently more memorable than others. To estimate the potential contribution of items to SME, I provided participants a fixed set of items during encoding, which allowed me to model item-specific contributions to recognition memory strength ratings using a linear mixed effect (LME) model. Using these item-based estimates, I was then able to isolate two distinct item-related activations during encoding that were linked to item distinctiveness and general item memorability, respectively. However, the residual of the LME model which reflects recognition strength unaccounted for by the items recovered the majority of original areas linked to subsequent recognition. Thus, I conclude that SMEs are largely attributable to encoding-related processes unique to each subject. Nevertheless, proper modeling and statistical control of item-driven effects afforded detection of originally missed encoding-activations and resulted in a SME more robust than the original. Taken together, these findings suggest that the SME reported in the literature is largely independent of the specific items encoded and demonstrates the need for different functional interpretations of item- versus subject-driven SMEs.
Chair and Committee
Ian G. Dobbins
David A. Balota, Kathleen B. McDermott, Jonathan E. Peelle, Henry L. Roediger, III,
Cha, Jihyun, "Isolating Item and Subject Contributions to the Subsequent Memory Effect" (2019). Arts & Sciences Electronic Theses and Dissertations. 1889.
Available for download on Wednesday, November 04, 2020