title: Perceptual narrowing towards adult faces is a cross-cultural phenomenon in infancy: a behavioral and near-infrared spectroscopy study with Japanese infants.
abstract: Recent data showed that, in Caucasian infants, perceptual narrowing occurs for own-race adult faces between 3 and 9 months of age, possibly as a consequence of the extensive amount of social and perceptual experience accumulated with caregivers and/or other adult individuals of the same race of the caregiver. The neural correlates of this developmental process remain unexplored, and it is currently unknown whether perceptual tuning towards adult faces can be extended to other cultures. To this end, in the current study we tested the ability of 3- and 9-month-old Japanese infants to discriminate among adult and infant Asian faces in a visual familiarization task (Experiment 1), and compared 9-month-olds' cerebral hemodynamic responses to adult and infant faces as measured by near-infrared spectroscopy (NIRS) (Experiment 2). Results showed that 3-month-olds exhibit above-chance discrimination of adult and infant faces, whereas 9-month-olds discriminate adult faces but not infant faces (Experiment 1). Moreover, adult faces, but not infant faces, induced significant increases in hemodynamic responses in the right temporal areas of 9-month-old infants. Overall, our data suggest that perceptual narrowing towards adult faces is a cross-cultural phenomenon occurring between 3 and 9 months of age, and translates by 9 months of age into a right-hemispheric specialization in the processing of adult faces.
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Japan.|Japan Society for Promotion of Science, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Psychology, University of Milano-Bicocca, Italy.
authors.forename: Viola
authors.initials: V
authors.lastname: Macchi Cassia
authors.affiliation: Department of Psychology, Japan Women's University, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Kanazawa
authors.affiliation: Department of Psychology, Chuo University, Japan.
authors.forename: Masami K
authors.initials: MK
authors.lastname: Yamaguchi
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kakigi
mesh_terms: D000328:Adult; D044466:Asian People; D001288:Attention / Q000502:physiology; D003431:Cross-Cultural Comparison; D004192:Discrimination, Psychological / Q000502:physiology*; D005145:Face; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D021641:Recognition, Psychology / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D044465:White People