Attentive and pre-attentive mechanisms of auditory stream segregation: An investigation using event-related brain potentials.
Item
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Title
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Attentive and pre-attentive mechanisms of auditory stream segregation: An investigation using event-related brain potentials.
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Identifier
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AAI9820582
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identifier
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9820582
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Creator
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Sussman, Elyse Suzane.
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Contributor
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Adviser: Walter Ritter
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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, Cognitive | Psychology, Physiological
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Abstract
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There is uncertainty concerning the extent to which the auditory streaming effect is a function of attentive or pre-attentive mechanisms of the auditory system. The streaming effect is an auditory phenomenon that occurs when alternating tones in high and low frequency ranges result in the experience of two segregated streams of sound, one made up of high tones and one made up of low tones. The mismatch negativity (MMN), a component of event-related brain potentials, which indexes pre-attentive acoustic processing, was used as a probe to determine whether the segregation associated with the streaming effect occurs pre-attentively.;In Experiment 1, a sequence of six different high (H) and low (L) tones were presented at fast and slow paces, while subjects ignored the stimuli. At the slow pace, the tones were heard as alternating high and low pitches, and no MMN was elicited. When the tones were alternated at a fast pace inducing a streaming effect, a pattern of standards emerged separately in each stream (e.g., H1-H2-H3), with a deviant pattern occurring infrequently within each stream (e.g., H3-H2-H1). An MMN was observed for the low frequency stream at the rapid stimulus presentation, indicating a pre-attentive locus for the streaming effect. The high frequency deviant, which immediately followed the low frequency deviant, did not elicit an MMN.;In Experiment 2 a streaming condition was run with a wider interval between the across-stream deviants than used in Experiment 1. MMNs were obtained to both the high and low deviants when the interval between the across-stream deviance was widened to more than 250 msec, indicating that the MMN system is susceptible to processing constraints.;For Experiment 3, subjects were presented with sequences of alternating high and low tones occurring at a constant rate, to investigate the affect of attention on stream segregation. When subjects ignored the stimuli, no MMNs were obtained. When subjects selectively attended the high-pitched tones, MMNs were obtained to the deviants within both the attended and unattended streams. The results indicate that attention can produce segregation altering the organization of sensory input in the early stages of acoustic processing.
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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.
