Emotional expressiveness of 5–6 month-old infants born very premature versus full-term at initial exposure to weaning foods

Facial expressions of 5–6 month-old infants born preterm and at term were compared while tasting for the first time solid foods (two fruit and two vegetable purees) given by the mother. Videotapes of facial reactions to these foods were objectively coded during the first six successive spoons of each test food using Baby FACS and subjectively rated by naive judges. Infant temperament was also assessed by the parents using the Infant Behaviour Questionnaire. Contrary to our expectations, infants born preterm expressed fewer negative emotions than infants born full-term. Naive judges rated infants born preterm as displaying more liking than their full-term counterparts when tasting the novel foods. The analysis of facial expressions during the six spoonfuls of four successive meals (at 1-week intervals) suggested a familiarization effect with the frequency of negative expressions decreasing after tasting the second spoon, regardless of infant age, type of food and order of presentation. Finally, positive and negative dimensions of temperament reported by the parents were related with objective and subjective coding of affective reactions toward foods in infants born preterm or full-term. Our research indicates that premature infants are more accepting of novel foods than term infants and this could be used for supporting the development of healthy eating patterns in premature infants. Further research is needed to clarify whether reduced negativity by infants born prematurely to the exposure to novel solid foods reflects a reduction of an adaptive avoidant behaviour during the introduction of novel foods.