The conventional view of development in human infancy is that objective awareness of the surrounding world is gradually constructed during the first 2 years through the infant's actions on the environment. However, recent work on the perceptual abilities of young infants indicates that even newborns perceive objective properties of their surroundings, detecting depth and displaying perceptual constancies that have hitherto been attributed only to older infants. In consequence it is necessary to revise our model of infant development. Since evidence points to objective perception from birth there is no need to postulate developmental processes that lead to its construction during development. However, as infants gain new capabilities for acting on the world, they have to develop knowledge of how these actions relate to the perceived world. It is suggested that this sort of knowledge is constructed through active experience.