Functional lateralization of newborn headturning to binaural speech and heartbeat sounds.
Item
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Title
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Functional lateralization of newborn headturning to binaural speech and heartbeat sounds.
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Identifier
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AAI9521267
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identifier
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9521267
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Creator
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Ecklund-Flores, Lisa J.
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Contributor
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Adviser: Gerald Turkewitz
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Date
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1995
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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, Developmental | Psychology, Psychobiology
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Abstract
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These studies explore the relationship between the acoustic and temporal characteristics of voices and newborn patterns of responsiveness to voices, suggesting possible prenatal sources for differential responsiveness. In a series of five studies, functional asymmetries in newborns are examined by recording headturning from midline to binaurally presented sounds. Presentation is equivalent to both ears, making differences in lateralized patterns of response indicative of differences in underlying patterns of sensorimotor processing. Headturns to unfiltered female speech sounds are examined in contrast to headturns to (1) intrauterine heartbeat sounds; (2) female speech low-pass filtered at 500 Hz; (3) female speech high-pass filtered at 3500 Hz; (4) female speech band-pass filtered between 1500 and 3000 Hz; (5) a phrase of low-pass filtered speech repeated at the rate of the intrauterine heartbeat, termed "Heartspeech"; and, in each study, a no-stimulus control.;Fifty-nine full-term newborns ranging in age from 22 to 55 hours (mean age 36 hours) were presented with eighteen 20 sec stimulus trials via 10 cm speakers bilaterally placed approximately 15 cm from each ear of the supine infant. Each baby's head was centered at midline preceding the onset of each stimulus trial. Results show a robust, asymmetric pattern of headturning occurs in most newborns' responses to binaurally presented unfiltered female speech sounds, with increased initial rightward orientation demonstrated in five replications. Low-pass filters and band-pass filters of female speech sounds do not significantly alter this rightward orientation bias, although high frequency speech sounds ({dollar}>{dollar}3500 Hz) result in an equal propensity to turn right or left, and seem limited in their effectiveness in producing a headturn in male babies. Heartbeat sounds, and "heartspeech" sounds failed to generate the rightward orientation bias.;Female speech sounds are a particularly salient class of stimuli for the organization of lateral biases in orienting in newborns, related to the naturally occurring prosodic characteristics of speech sounds. Examination of the responses of individual babies to unfiltered female speech reveals a distribution of orientation biases, with the majority of babies showing a rightward headturning bias, but a cluster of babies demonstrating a leftward headturning bias.
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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.
