Stability in young infants’ discrimination of optic flow

Although considerable progress has been made in understanding how adults perceive their direction of self-motion, or heading, from optic flow, little is known about how these perceptual processes develop in infants. In 3 experiments, the authors explored how well 3- to 6-month-old infants could discriminate between optic flow patterns that simulated changes in heading direction. The results suggest that (a) prior to the onset of locomotion, the majority of infants discriminate between optic flow displays that simulate only large ( 22°) changes in heading, (b) there is minimal development in sensitivity between 3 and 6 months, and (c) optic flow alone is sufficient for infants to discriminate heading. These data suggest that spatial abilities associated with the dorsal visual stream undergo prolonged postnatal development and may depend on locomotor experience. Mobile organisms must accurately determine their direction of self-motion, or heading, in order to control body posture, avoid collisions, and move quickly and efficiently through the environ-ment. There are a number of potential sources of information about heading direction (Cutting, Springer, Braren, & Johnson, 1992), but one of the most important and widely studied is optic flow, the pattern of visual motion generated by an observer moving through a rigid environment (Gibson, 1966, 1979). Extensive empirical investigations have shown that adult observers can determine heading direction from optic flow with a high degree of accuracy (Warren, 1998). Moreover, rudimentary sensitivity to optic flow patterns simulating either an object’s approach toward the face or the forward/backward motion of the observer emerges within the first several weeks and months after birth (Bertenthal & Bai, 1989