The effect of stimulus variation on the newborn's headturning response was assessed using an habituation-recovery paradigm. Stimuli, differing in content and number of distinct syllables, were presented through off-center loudspeakers to examine the impact of increasing stimulus variability/information on the newborn's auditory attention. Seventy-two neonates were randomly and equally assigned to one of 4 groups: a One Syllable group that heard the same syllabus (e.g., ta-ta); a Three Syllable group that heard three syllables (e.g., pu-pu-ti-ti-ka-ka); a Six Syllable group that heard six syllables (e.g., pi-pi-ta-ta-ku-ku-pa-pa-tu-tu-ki-ki); and a Nine Syllable group that heard nine different syllables (e.g., pi-pi-ta-ta-ku-ku-pa-pa-tu-tu-ki-ki-pu-pu-ti-ti-ka-ka). The duplicated syllables were presented at a rate of 1/sec from either a left or right speaker for 20 trials, with a trial duration of 18 seconds. Following twenty habituation trials, all infants received five trials of a rattle stimulus. The frequency of correct headturns toward the direction of the sound source served as the dependent variable. Analyses revealed that all infants habituated headturning across syllable trials and recovered their responding to the rattle trials. Examination of initial headturning behavior, however, revealed that infants in the Three Syllable group oriented significantly more toward the stimulus (89% of the trials), in comparison to the One Syllable (74%) and Nine Syllable (72%) groups, respectively, suggesting that the moderately varying stimulus was most successful in recruiting attention. The Six Syllable group, with an initial frequency of 80% of headturns toward the sound, did not differ significantly from any other group, although the stimulus' efficacy in recruiting attention measured half-way between the minimal efficacy of the one- and nine-syllable stimuli and the maximum efficacy of the three syllable stimulus. No group differences were found in the stimuli's efficacy in maintaining attention across trials, in that infants in all groups habituated headturning at comparable levels. In sum, these findings imply that moderately varying stimuli are most successful in initially recruiting attention, while highly varying stimuli or nonvarying stimuli are less efficacious. However, following this initial difference, the level of the stimulus variation did not influence infants' subsequent behavior across habituation trials.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-8333 |
| Date | 01 January 1992 |
| Creators | Swain, Irina Uta |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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