Date of Award


Degree Name

Master of Science (MS)




Amy H. Criss

Subject Categories

Social and Behavioral Sciences


To study episodic memory in a laboratory, we study interference within a list of stimuli. With list strength paradigm, we study how such interference is affected by how well stimuli are encoded, and the encoding strength of other items in the list. A stimulus can be weak or strong, and it can be in a pure list, composed of all weak or all strong stimuli, or a mixed list, composed of both weak and strong stimuli. A list strength effect (LSE) refers to the interaction between stimulus strength and list type. In free recall, where the cue used at test is only context, we have consistently observed a LSE. Yet, in cued recall, where the cue is made of item, we have consistently observed a null LSE. Thus, we attributed the source of LSE to the type of cue used at retrieval. Based on REM, this framing is potentially misleading. It is not the type of cue (context or item) that is critical, but the level of competition. Typical experiments have confounded these two factors because they have manipulated item to create a low level of competition within a list, while context to create a high level of competition. Therefore, in this study, we manipulated the level of competition (between-subject) and the type of cue (within-subject) simultaneously on the list strength paradigm. Data shows LSE was determined by the level of competition, not the type of cue probing memory at test. Fitting REM to the data confirms this statement. Nevertheless, whether memory was cued with context or item affected recall performance differently.


Open Access

Available for download on Saturday, September 08, 2018