Startle probe reflex in response to lateralized presentation of pleasant, neutral and unpleasant odors.
Item
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Title
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Startle probe reflex in response to lateralized presentation of pleasant, neutral and unpleasant odors.
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Identifier
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AAI9908338
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identifier
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9908338
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Creator
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Kuhl, Sandra Brown.
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Contributor
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Adviser: Howard Ehrlichman
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Date
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1998
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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 | Biology, Neuroscience | Psychology, Physiological
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Abstract
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Many studies have supported the theory that the human startle reflex is modulated by affective stimuli, including two studies which used odors as affective stimuli. The present study was conducted to determine whether modulation of the startle reflex in response to lateralized presentations of odors was better predicted by the valence hypothesis, which postulates that the right hemisphere is specialized for processing of unpleasant stimuli and the left hemisphere is specialized for processing of pleasant or the right hemisphere hypothesis, which postulates that the right hemisphere is specialized for processing of both pleasant and unpleasant stimuli. A between subjects design was used wherein half of 80 right-handed participants were presented with pleasant and half with unpleasant odors. Startle reflexes to acoustic probes were measured as blink magnitudes ({dollar}\mu{dollar}V) while participants were monorhinically presented with valenced odors: coconut (pleasant), room air (neutral) and Limburger cheese (unpleasant). Heart rate responses, gender effects and verbal self-report of mood, arousal, hedonics and intensity to the odors also were measured.;As predicted, a startle modulation interaction was found. There was startle blink attenuation during pleasant odor presentation and augmentation during unpleasant odor exposure. Moods also were rated more positively during pleasant odor presentation and more negatively during unpleasant odor presentation. Compared to startle reflexes, heart rate did not as sensitively differentiate responses to valenced odors, as heart rate increased only during unpleasant odor exposure. With both startle and heart rate measures, females were more physiologically responsive to odors. Although the proposed startle interaction between laterality and valence of odors was not found, lending no support for either of the hemispheric hypotheses, an unexpected interaction of Nostril (left/right) x Valence (pleasant/unpleasant) x Breath Direction (inhalation/exhalation) was found. Left pleasant odor inhalations produced the smallest blink magnitudes and right unpleasant odor exhalations produced the largest blink magnitudes. These findings were most consistent with the valence hypothesis and were further discussed in terms of (1) Zajonc's vascular theory of emotional efference, regarding the hedonic effects of warmed and cooled air; and (2) inhalations and exhalations as behavioral correlates of approach and withdrawal.
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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.
