Kinematic Foundations of Infant Visual Perception
Philip J. Kellman Swarthmore College
If asked what aspect of vision means most to them, a watchmaker may answer "acuity," a night flier "sensitivity," and an artist "color." But to animals which invented the vertebrate eye, and hold the patents on most of the features of the human model, the visual registration of motion was of the greatest importance.
-- Walls, 1942, p. 342
Only mobile organisms have elaborate perceptual systems, and their functions are tied to motion in multiple ways. The most obvious importance of registering motion involves the detection of moving things, which may pose danger, offer nutrition, and so on. No less important is the registration of self-motion: the use of optical information to guide locomotion and other activities. In recent years, another central role of motion has been recognized and elaborated, most clearly in visual perception: The motions of objects and observers furnish information about persisting properties of the environment, such as objects and spatial layout ( J. J. Gibson, 1966, 1979; Johansson, 1970; Johansson, von Hofsten, & Jansson, 1980). Information given by spatiotemporal changes or kinematic information has been argued to be central in mature perception because of its greater accuracy in specifying properties of the environment, and because perceivers seem specially equipped to utilize it ( Braunstein, 1976; J. J. Gibson, 1966, 1979; Johansson et al., 1980). In this chapter, I connect these notions of the primacy of kinematic information about objects and events with a conjecture about the development of visual perception: Kinematic information may be fundamental to the earliest perceptual capacities. The initial abilities of human