Abstract
Matured visual system extracts invariants from natural images to estimate properties of external objects such as shape and material, meanwhile it discounts information variant with viewpoint and illumination. For instance, we easily judge the glossiness of a surface, but rarely care about the reflected pattern of a scene (lightfield) on the surface (visual equivalence: Ferwada, 2008). To understand when and how such a computational scheme is acquired during development, we examined whether infants aged 3-8 months can detect changes in the surface glossiness and changes in the reflected lightfield that adults cannot see. Two pairs of computer-generated images were used: one pair consisted of glossy and matte images rendered from the same 3D object, and another pair consisted of two glossy images rendered with two slightly different lightfields. One pair of these two was presented alternately with a 200 ms ISI (change images) in one side. In the other side, an image chosen from the corresponding image pair was presented repeatedly (no-change images). We measured the spontaneous preference of infants for the changing images over the no-change images. The results showed that infants aged 7-8 months, but not 3-6 months, preferred the change in the surface glossiness. In contrast, infants aged 3-4 months, but not 5-8 months, preferred changes in the reflecting lightfield. Proportion of preferential looking was correlated with the month of age positively for the surface change (r=0.529) and negatively for the lightfield change (r=-0.504). Similar results were obtained for stimuli synthesized using Portilla-Simoncelli's algorithm. These findings support the notion that the visual system declines from reacting directly to image inputs at 5-6 months old as it complementarily develops to represent external surfaces or relevant image statistics at 7-8 months old.
Meeting abstract presented at VSS 2014