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.

The neural basis of responsive caregiving behaviour: Investigating temporal dynamics within the parental brain

“…Infant cues play two primary roles in establishing the relationship between infant and caregiver. First, these cues provide the adult caregiver with a wealth of information about the infants' physiological and affective state [10][11][12]. In combination with other contextual factors, these signals help to guide the selection of appropriate caregiving behaviour.…”

Facial expressions in school-aged children are a good indicator of ‘dislikes’, but not of ‘likes’

“…The application of facial expressions has revealed that infants can recognize and discriminate between various basic tastes and odours (Berridge, 2000;Ganchrow, Steiner, & Daher, 1983;Rosenstein & Oster, 1988;Steiner, 1973;Steiner, Glaser, Hawilo, & Berridge, 2001). Newborn infants show differentiated facial responses to various basic solutions: a sweet taste elicits facial relaxation, sucking, tongue protrusions and may lead to a smile; a sour taste elicits lip pursing; a bitter taste gives rise to head turns, mouth gaping, nose wrinkling and lowered mouth corners; and a salty taste has a less distinctive pattern (Ganchrow et al, 1983;Oster, 2004;Rosenstein & Oster, 1988;Steiner, 1973;Steiner et al, 2001). Although many variations of these expressions are displayed by infants (Rosenstein & Oster, 1988), the system is quite robust at that age, since infants with head abnormalities also reveal this pattern of facial expressions towards basic tastes (Steiner, 1973).…”

A Systematic Integrative Review of Infant Pain Assessment Tools

“…Between 1978 and 2004, 17 unidimensional pain assessment tools were published in the literature [25][26][27][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] ; the most recent was published in 2001. One unpublished tool, the Mills Infant and Toddler Pain Index, which was based on the work of others, 11 was also identified.…”

“…A number of these tools were developed expressly for use in research. 27,32,[44][45] The extent of psychometric testing varies by tools (see Table 2). Many require extensive training to use and interpret, making clinical utility impractical.…”