Infant's ability to form a common representation of an object's shape from different pictorial depth cues: A transfer-across-cues study

The purpose of this study was to explore the infants' ability to perceive 3D shape from pictorial depth cues. While several previous studies showed that infants discriminate between displays which differ in pictorial information for depth and can use this information to direct reaching, it is not clear that infants form a common representation of an object's shape from different pictorial depth cues. To clarify the infants' ability for pictorial depth cues, we employed a "transfer-across-depth-cues" method with four-to-five-month-old and six-to-seven-month-old infants. Using this method, we examined the transfer between two pictorial depth cues: shading and surface contours. Infants were habituated to a 3D shape specified by one cue and were then presented with the same shape and a novel shape, both specified by the other depth cue. In this situation the familiar shape could be detected only if one perceived the 3D shape from the pictorial depth cues. Our results indicated that older infants showed a significant novelty preference while the younger group did not. We found that, at least by six-to-seven-months old, infants develop a common representation over different pictorial depth cues.