Development of infants' sensitivity to surface contour information for spatial layout

The development of sensitivity to a recently discovered static-monocular de pth cue to surface shape, surface contours, was investigated. Twenty infant s in each of three age groups (5, 51/2, and 7 months) viewed a display that creates an illusion, for adult viewers, that what is in fact a frontoparal lel cylinder is slanted away in depth, so that one end appears closer than the other. preferential reaching was recorded in both monocular and binocul ar conditions. More reaching to the apparently closer end in the monocular than in the binocular condition is evidence of sensitivity. Infants aged 7 months responded to surface contour information, but infants aged 5 and 51/ 2 months did not. In a control study, twenty 5-month-old infants reached co nsistently for the closer ends of cylinders that were actually rotated in d epth. As findings with other static-monocular depth information suggest, in fants' sensitivity to surface contour information appears to develop at app roximately 6 months.