Evolutionary Perspective to the Origins ot Languages
— A Behavioral Consideration—

Abstract

    Mothers tend to jiggle their newborn infants at the breast, or jiggle the bottle, during pauses in the newborn's sucking. When observing mothers' natural and unconstrained feeding of their infants at ages 2 weeks and 8 weeks, the cessation of jiggling proved to be a better elicitor of a resumption of sucking than the jiggling itself. An experiment in which bottles were jiggled according to a predetermined, controlled schedule showed that this phenomenon is due to a contingent response on the part of the infant rather than mothers'anticipation of the burst. Thus the feeding can appear to be an exchange of turns, in which the infant's pause is answered by the mother's jiggling and the end of jiggling is answered by the next burst. Mothers shorten their jiggling over the first 6 weeks. Infants' pauses also grow shorter. Finally such behavioral characteristics are reported to be seen in rudimentary forms in vocal behavior of nonhuman primates.