Development of visual organization: the perception of subjective contours.

This study examines the development of infants' sensitivity to the organization of a subjective-contour stimulus array. 5- and 7-month-olds were sequentially shown 3 stimulus arrays of elements, only 1 of which was capable of producing subjective contours. Only the orientational relations among elements was varied. An infant habituation control procedure was used to test infants' abilities to discriminate these arrays. The results indicated that (1) only 7-month-olds showed consistent differential responsiveness to changes from an illusory array to a nonillusory array or vice versa, (2) 5-month-olds showed a weaker tendency to respond similarly and only when they had prolonged experience with the illusory array, and (3) neither age group showed much response recovery to a change from one nonillusory array to another. These findings are interpreted as indicating that infants can perceive subjective contours. However, the age of this accomplishment probably varies with both the characteristics of the array and the abilities of the observer.