No own-age bias in 3-year-old children: more evidence for the role of early experience in building face-processing biases.

This study aimed to investigate the presence of an own-age bias in young children who accumulated different amounts of early experience with child faces. Discrimination abilities for upright and inverted adult and child faces were tested using a delayed two-alternative, forced-choice matching-to-sample task in two groups of 3-year-old children, one composed of first-born children and the other composed of children who, from the time of their birth, had daily exposure to a child face through the presence of an older sibling in their home. Children without an older sibling were better at differentiating among adult faces than among child faces and showed an inversion effect that was selective for adult faces. Children with an older sibling were equally skilled at differentiating upright adult and child faces and showed inversion effects of comparable magnitude for both face types. Results support the notion that face representational space of younger children is tuned to adult faces and suggest that age biases during early childhood are dependent on the effects of early experience.