Date of Award

6-26-2026

Date Published

August 2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

Advisor(s)

David Kellen

Keywords

computational modeling;context drift;episodic memory;output interference;recognition memory;test position effect

Subject Categories

Cognitive Psychology | Psychology | Social and Behavioral Sciences

Abstract

Test position effect refers to the decline in memory performance over the course of testing. Two main competing accounts attribute this effect either to output interference, in which retrieval and updating processes degrade memory representations while encoding processes add new traces, or to context drift, in which gradual changes in context reduce overlap with the study context used to retrieve memories. The present dissertation examines the mechanisms underlying the test position effect through analyses of existing datasets from the literature and three new empirical studies while utilizing computational models, namely the Retrieving Effectively from Memory (REM) model and the Global Matching Model (GMM). First, analyses of existing datasets reestablished the viability of REM’s output interference account in explaining several findings previously argued to favor context drift, including patterns observed across alternative forcedchoice tasks and the simultaneous effects of list length and test position. Three new experiments further examined the test position effect. Experiment 1 investigated how study strength influences the test position effect, particularly in alternative forced-choice tasks where response bias is likely minimized. Experiment 2 manipulated test trial composition in a four-alternative forced-choice task by comparing conditions in which participants identified either an old item among new items or a new item among old items. Experiment 3 examined the influence of response bias by manipulating the proportion of old and new items across test lists. Together, these findings contribute to a more nuanced understanding of the test position effect in terms of how interference from items and contexts may affect memory over the course of retrieval.

Access

Open Access

Available for download on Tuesday, August 03, 2027

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