Differential Facial Responses to Four Basic Tastes in Newborns

Abstract

This chapter reports two studies that were designed to provide a more stringent test of whether newborns show differential facial responses to sour, bitter, and salty solutions as well as a greater discrimination between sweet and nonsweet tastes. The first study involved a detailed and objective coding of infants' facial responses to sweet, sour, salty, and bitter solutions. In the second study, naive observers shown videotapes of the infants' facial responses rated the infants' hedonic responses and attempted to identify the eliciting stimulus. The results from both the direct measurement and judgment studies demonstrate the usefulness of facial expression as a response measure for studying the newborn infant's chemical sensory capacities and hedonic predispositions. The Rosenstein and Oster (1988) study illustrates the unique advantages of the Baby Facial Action Coding System (FACS) for investigating the innate sensory capacities and hedonic responses of newborn infants. The study addressed more general questions about the differentiation of facial expressions and their relation to emotional feeling states in young infants.