Previous studies have shown that the development of global form perception in humans is gradual when compared to other basic visual functions (e.g. visual acuity). The development of basic visual functions is mirrored in human and non-human primates. Few investigations of the development of object recognition and global form perception have been conducted in primate infants. A few studies of human infants suggest that global form perception is present near birth, while data from children suggest that it develops around age 5 years or later. Most studies of children confound development of language and perception, or specifically instruct the participants. To avoid these confounds, we used an animal model and Kanizsa illusory contours as an assay of global form perception. We recently showed that 1.5 year-old macaque monkeys demonstrate the ability to perceive Kanizsa illusory forms (Feltner & Kiorpes, VSS, 2008). We have now studied the time period during which this ability develops.