Unitization and semantic information

Hubbard, Ryan

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https://hdl.handle.net/2142/50679 Copy

Description

Title

Unitization and semantic information

Author(s)

Hubbard, Ryan

Issue Date

2014-09-16

Director of Research (if dissertation) or Advisor (if thesis)

• Federmeier, Kara D.
• Gonsalves, Brian D.

Department of Study

Psychology

Discipline

Psychology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.A.

Degree Level

Thesis

Keyword(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.

Graduation Semester

2014-08

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http://hdl.handle.net/2142/50679

Copyright and License Information

Copyright 2014 Ryan Hubbard

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