ReviewUnderstanding infant eating behaviour - Lessons learned from observation

- Infants signal appetite through their interest or disinterest in food
- Infants use rapid and transient facial expressions to signal liking
- They use subtle or potent gestures, bodily movements and vocalisations to express wanting
- Coding infant communication and caregiver response using video capture reveal the nature of mealtime interactions
- Responsiveness to infant communication can promote self-regulation

Observations of human infants during feeding presents a rich source of data to identify the ways in which hunger, appetite and satiety are communicated in early life. Infants signal appetite through their interest or disinterest in food using a series of communication cues from rapid and transient facial expressions to subtle or potent gestures and bodily movements through to vocalisations and eventually speech. Even in the first days of life facial expressions in response to basic tastes are clearly demonstrated and shared between human infants, other primates and the rat. These sensory typical reactions are said to have biological significance since the positive affective response to sweet taste secures a safe and useful source of energy whilst an aversive response to bitter may protect against toxicity. However, beyond these shared responses to basic tastes, the human infant has a sophisticated communication system to demonstrate readiness to eat, avid or waning appetite and satiety. Video capture and behavioural coding of infant communication and caregiver responses during meals reveal the dynamic nature of mealtime interactions. Responsiveness to infant cues is influenced by maternal characteristics and mode of feeding. Breastfeeding facilitates communication by enhancing maternal responsiveness and increasing the frequency of engagement and disengagement cues of the infant. This demonstrates the bi-directionality and interdependence of infant communication during a feed, namely that more responsive feeding for example, through breastfeeding, is associated with more proficient communication by the infant. Overall, observational methods have revealed the complex ways in which infants signal energy needs to their caregivers, and in turn these same methods have captured on film the ways in which carers recognise and react to these signals as part of responsive feeding. Potential applications of these methods includes developing interventions to facilitate infant self-regulation through responsive feeding.