Differential Facial Responses to Four Basic Tastes in Newborns

Abstract

The distinctiveness and recognizability of taste-elicited facial expressions in newborns were examined in 2 studies. Sucrose, sodium chloride, citric acid, and quinine hydrochloride solutions were presented to 12 infants at 2 hours of age. In Study 1, the anatomically based Facial Action Coding System adapted for infants (Baby FACS) was used to obtain detailed, objective descriptions of the infants' videotaped facial responses to each solution. Facial responses to sucrose were characterized primarily by facial relaxation and sucking. The responses to salty, sour, and bitter solutions shared the same hedonically negative upper- and midface components but differed in the accompanying lower-face actions: lip pursing in response to sour and mouth gaping in response to bitter. There was no distinctive facial expression for sodium chloride. These findings demonstrate that newborns differentiate sour and bitter from each other and from salt, as well as discriminating sweet versus nonsweet tastes. In Study 2, untrained adults viewing videotapes of the infants' facial reactions made forced-choice judgments identifying the stimuli presented and rated the hedonic tone of the infants' responses. While the judges accurately identified the newborns' responses to sucrose, there were systematic errors in their judgments of the 3 nonsweet stimuli. The judges' hedonic ratings, on the other hand, clearly differentiated between the infants' responses to the bitter stimulus and the other 3 tastes. The findings are discussed in terms of the possible functional origins and communicative value of taste-elicited facial expressions in infants.

Prenatal and Postnatal Flavor Learning by Human Infants

“…22 Because previous research 15,23,24 has shown that negative facial configurations are more discriminating than positive configurations in gauging the infants' hedonic responsiveness, the videotape analyses focused on frequency of negative facial responses (eg, nose wrinkling, brow lowering, upper lip raising, gaping, head turning) made in response to each spoonful of cereal proffered. During scoring, the sound was turned off so that the raters would not be influenced by the infants' vocalizations.…”

Establishing good dietary habits – capturing the minds of children

“…The newborn baby shows innate preferences for sweet tastes and innate dislikes for sour or bitter tastes 1,2 . From an evolutionary perspective these innate acceptance patterns serve as important biological functions, since in nature sweetness is associated with readily available calories from carbohydrates, and bitterness is correlated with toxicity 3 .…”

Contextual determinants of anger and other negative expressions in young infants.

“…For example, tickling, having the infant taste lemon juice in contrast to sweet and bitter solutions, sudden violations such as that produced by a jack-inthe-box, the entry of a masked stranger, arm restraint, or removal of a teething biscuit have all been used to elicit facial expressions in young infants (Bendersky, Sullivan, Alessandri, & Lewis, 1995;Braungart-Reiker & Stifter, 1996;Charlesworth, 1969;Fox & Davidson, 1986;Granchrow, Steiner, & Daher, 1983;Kochanska, Coy, Tjebkes, & Husarek, 1998;Rosenstein & Oster, 1988;Scarr & Salapatek, 1970;Skarkin, 1977;Sroufe & Wunsch, 1972;Steiner, 1979;Stenberg, Campos, & Emde, 1983). These situations represent only a sample of the various contexts that have been devised.…”