Abstract
Children perform more poorly than adults on tests of face identification yet the source of their difficulty is controversial, with recent evidence pointing to general cognitive immaturity rather than differences in the use of specialized face-coding mechanisms such as holistic coding. However, not all aspects of children's face coding are well studied and relatively little is known about children's face-space. Immaturity in face-space is therefore a potential source of children's face identification difficulties. We used face identity aftereffects to investigate children's face-space. Previous studies have shown that 8 year-olds experience face identity aftereffects and their aftereffects do not differ quantitatively from adults'. In the present study we tested younger children and found that face identity aftereffects were present as early as 4-5 years-of-age and did not change quantitatively between 5 and 8 years-of-age. However, children's aftereffects, including those of 8 year-olds, were larger than adults' suggesting that children's face-space may not be mature by 8 years-of-age. We then conducted additional tests to determine whether a major qualitative change in how faces are represented in face-space could occur between 8 years-of-age and adulthood. Specifically we investigated whether children's face identity aftereffects, like those of adults, reflect norm-based coding or instead result from exemplar-based coding. These tests showed that children's face-space coding is norm-based because (1) children's face identity aftereffects were larger for adaptors far from the norm than for adaptors closer to the norm, (2) children's aftereffects were larger for opposite adapt-test pairs than non-opposite pairs equated for perceptual similarity and (3) children perceive faces close to the average as “neutral” for identity. We conclude that there is no evidence of a qualitative change from exemplar to norm-based coding between 8 years and adulthood. Children's larger aftereffects may reflect other immaturities in children's face-space such as more flexible norms.
Australian Research Council Discovery Grants DP0770923, DP0877379,DP0984558.