The perception of illusory transparent surfaces in infancy: early emergence of sensitivity to static pictorial cues.

Most developmental studies consistently show that sensitivity to purely pictorial cues to perceptual organization emerges around 6-7 months of age (e.g. B. I. Bertenthal, J. J. Campos, & M. M. Haith, 1980). Here, we show evidence for an early emergence of visual completion using purely static two-dimensional pictorial information. By using preferential looking technique, we examined whether 3-4 and 5-6 month-olds perceive illusory transparent surface which is induced by a newly developed mixed polarity Kanizsa configuration. Our results suggest that 3-4 and 5-6 month-olds discriminate and prefer the transparent Kanizsa configuration both from its rotated counterpart, and from the non-transparent Kanizsa configuration. Our stimuli and experimental manipulation exclude the possibility that these responses were based on the geometrical properties of the figure or the local contrast difference between the figures. Our finding suggests the sensitivity for surface segmentation based solely on two-dimensional cues in both 3-4 and 5-6 month olds.