Peter S. Kaplan Michael H. Goldstein Michael J. Owren
Psychol. Dept., Univ. of Colorado, P.O. Box 173364, Denver, CO 80217-3364
A habituation--dishabituation paradigm was used to study acoustic characteristics of adults' infant-directed (ID) speech that elicit infant visual attention. Five groups of 4-month-olds received twelve 10-s presentations of a checkerboard pattern. On the ninth trial, one of five auditory stimuli was presented. Differences in looking duration were compared on the trials before and after the auditory stimulus. Attention increased significantly after presentations of a natural, intact ID speech segment and after a version composed of sine waves simulating its fundamental frequency (F[sub 0]) and first five harmonics (H[sub 1]--H[sub 5]). However, no significant changes in attention occurred following sine waves simulating the F[sub 0] only, the F[sub 0]-plus-H[sub 1], or the harmonics only. The harmonics-only stimulus elicited significantly less responding than did any other stimulus. The roles of frequency modulation and spectral properties are discussed.