The ontogeny of face recognition: Eye contact and sweet taste induce face preference in 9-and 12-week-old human infants

Nine and 12-week-old infants (N = 140) who were either calm or crying sat f acing a researcher for 3.5 min. The researcher gazed into the infant's eyes with a smiling face or looked above the infant's forehead. She delivered a 12% sucrose solution via a syringe or a pacifier, or she did not deliver a nything. After the exposure period. the mother held her infant over her sho ulder. Infant gaze direction was recorded while the infant faced the same r esearcher and a stranger. The confluence of sweet taste and eye contact was necessary and sufficient for calm 9- and 12-week-olds to form a preference for the researcher. Crying infants never did so, even though eye contact a nd sweet taste arrested crying. Different visual-gustatory combinations ind uced unanticipated affective states and are discussed within the contexts o f cognitive mechanisms that mediate face teaming and preference, the proxim ate mechanisms involved. and the evolutionary significance of face recognit ion.