The *perception of illusory contours by rhesus macaques (Macaca mulatta).
Item
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Title
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The *perception of illusory contours by rhesus macaques (Macaca mulatta).
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Identifier
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AAI3278445
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identifier
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3278445
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Creator
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Feltner, Kimberly Ann.
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Contributor
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Adviser: Sheila Chase
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Date
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2007
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology | Psychology, Behavioral
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Abstract
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A zero-delay matching-to-sample procedure (MTS) was used to determine whether rhesus macaque monkeys experience the illusory contours evident in human perception of the Kanizsa patterns. Prior to tests with an illusory square, parallelogram, and trapezoid, MTS training was given with patterns made of composites of grayscale squares or parallelograms. On some trials, a single square or parallelogram was used. Although prior to training with the composites, the monkeys readily learned to choose the matching one of two pictures only one of three monkeys met criterion, 80% correct, on the composite figures. Performance was particularly poor when the choice was between a single square and parallelogram where 7,500 trials were required to reach a criterion of 70% correct. When the square or parallelogram forms were presented as matches to their illusory forms on test trials selection of the match was at chance. However, the matching illusory trapezoid was chosen over one in another orientation on 69% of the trials, a percentage significantly above chance, p < .05. A test with three new illusory forms was done to determine whether failure to match the Kanizsa square and parallelogram was due to inattention resulting from exposure to these stimuli during training failed to provide clear evidence of the illusion. Weak evidence for the illusion was found when the spacing between the inducing contours was reduced to make the illusion more distinct. Further tests including training that was more similar to the test conditions (simpler stimuli, similarity matching) failed to yield evidence that the monkeys experienced the illusion.;It is possible that rhesus monkeys do see the illusory contours experienced by humans, however there is some evidence of anatomical differences from humans in layer 4A of primary visual cortex. Failure to obtain evidence for the illusion is more likely due to procedural variables used in these experiments such as failure to give sufficient training in similarity matching or requiring the monkeys to make fine discriminations between the choice stimuli.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
