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Title:Unitization and semantic information
Author(s):Hubbard, Ryan
Advisor(s):Federmeier, Kara D.; Gonsalves, Brian D.
Department / Program:Psychology
Discipline:Psychology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.A.
Genre:Thesis
Subject(s):Memory
semantic
event related potential (ERP)
N400
Abstract:Recognition memory can be supported by two distinct processes: recollection of an item and its related contextual information, and a general sense of familiarity for the item. Performance on recollection-based associative memory tests can be supported by familiarity when stimuli are “unitized”, or encoded as a single representation. Unitization generally produces greater positivity in mid-frontal (FN400) potentials during recognition in ERP studies, also suggesting recruitment of familiarity. However, several experimental manipulations can lead to FN400 modulation, as well as differences in estimates of familiarity; thus, it is unclear what mechanism underlies this increase in familiarity-based retrieval. One proposal is that unitization may modulate the semantic relatedness between the two items; thus, unitization of stimuli with little semantic content would lead to reduced effects. To assess this claim, two ERP experiments were performed with semantically sparse stimuli (abstract images and pseudowords), in which participants either unitized stimuli or encoded them separately, and were later tested for their memory for the items. Results suggest that unitization may still be possible with semantically sparse stimuli, but that the neural correlates of unitization (namely, the FN400) are affected by this manipulation.
Issue Date:2014-09-16
URI:http://hdl.handle.net/2142/50679
Rights Information:Copyright 2014 Ryan Hubbard
Date Available in IDEALS:2014-09-16
Date Deposited:2014-08


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