Behavioral Inhibition in Neonates Produced by Auditory Stimuli

The capacity of the newborn infant to respond to auditory stimulation with increased activation has been observed and studied by neonatal psychophysiologists for many years. Recent research (Bartoshuk, 1962; Bridger, 1961) has focused on the infant's capacity to become habituated to tones and to discriminate between tones of varying frequencies. In these studies an attempt was made to have the neonates quiescent prior to stimulation in order to achieve maximum receptivity. The ability of the infant to be soothed by auditory stimulation, although well known to mothers, has received little attention from those concerned with the scientific investigation of neonates. Music, the hum of motors, and the human voice are reported by mothers to calm irritable babies. However, these stimuli are complex, often involve other modalities, and may involve learning. As part of a research project investigating soothing and inhibition in neonates, an experiment was performed to measure the relative efficacy of a series of tones in soothing excited neonates. An attempt was made to see whether infants in high arousal levels would respond differentially to tones of various frequencies and, further, whether the rhythm of the sound would also be a factor that would facilitate or limit soothing.