CHANGING INFLUENCES OF SUCROSE AND VISUAL ENGAGEMENT IN 2-WEEK-OLD TO12-WEEK-OLD HUMAN INFANTS - IMPLICATIONS FOR MATERNAL FACE RECOGNITION

Healthy infants, 2- to 12-weeks of age, were studied while crying. Fol lowing a baseline period during which crying occurred for at least 24 s/min, each infant was allowed to taste 0.5-1.0 ml of a 12 % weight/vo lume solution of sucrose, or water vehicle, once/min. for 30 sec. whil e being visually engaged by the experimenter. Two-and 4-week-old infan ts were quieted by sucrose-visual engagement and remained quiet during the 2-min posttreatment interval. Six- and 9-week-old infants were qu ieted during treatment. Calm did not endure, however, and baseline lev els of crying were soon reachieved. Crying in 12-week-old infants was not reduced either during or following sucrose-visual engagement. Wate r only modestly reduced crying, and this was mainly attributed to resp onse competition during water ingestion. Quieting did not persist in i nfants who received water. Heart rate was dissociated from quieting in infants of all ages. Heart rate increased, despite reduced crying, in the youngest infants who received water. Heart rate was not reduced b y sucrose in 6- or 9-week-olds even though crying was. These data spea k to the adequacy of different facets of the nursing setting to calm d istraught infants and to support learning about the mothers specific f acial characteristics.