Degree Type

Dissertation

Date of Award

2006

Degree Name

Doctor of Philosophy

Department

Psychology

Major

Neuroscience

First Advisor

Eric E. Cooper

Second Advisor

Veronica J. Dark

Abstract

The coordinate relations hypothesis theorizes that the recognition system that mediates most basic-level object recognition is a structural description that represents shape using categorical relations whereas the recognition system that mediates face recognition represents shape via a coordinate relations representation. According to the coordinate relations hypothesis, the factor determining which visual recognition system mediates a given recognition task is the computational demands of the task. According to the coordinate relations hypothesis, if the visual recognition task requires distinctions to be made among stimuli that share the same structural description, then the task will be performed by the face recognition system. Further, the coordinate relations hypothesis predicts that any task requiring discrimination between objects that share the same structural description should be difficult for prosopagnosics because their coordinate system has been damaged, because according to the coordinate relations hypothesis, prosopagnosia results from damage to the coordinate recognition system which is required for any task that cannot be performed using a structural description representation;Experiments 1, 2, and 3 compared a prosopagnosic's ability to distinguish stimuli that either shared a common structural description or did not: discriminating animals, real objects, and nonsense objects. In all cases, the prosopagnosic showed massive problems with any task that required discrimination within a structural description just as predicted by the coordinate relations hypothesis. The purpose of Experiment 4 was to see if the prosopagnosic showed a deficit on a Kosslyn metric judgment task but not on a categorical judgment task. Once again, the prosopagnosic had significantly more difficulty with coordinate tasks indicating that the same neural mechanism may mediate coordinate tasks regardless of whether the visual recognition task involves coding the position of the primitives in the representation used for object recognition or judging the spatial distance between two different objects;The coordinate relations hypothesis correctly predicted the results of all of the experiments. That is, just as predicted by coordinate relations hypothesis, LB made significantly more errors than the controls on those trials that required discrimination within a structural description, but not on those trials that could be accomplished on the basis of structural descriptions.

DOI

https://doi.org/10.31274/rtd-180813-3379

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu

Copyright Owner

Glenn Eric Casner

Language

en

Proquest ID

AAI3229056

File Format

application/pdf

File Size

100 pages

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