One of the most powerful sources of information about spatial relationships available to mobile organisms is the pattern of visual motion called optic flow. Despite its importance for spatial perception and for guiding locomotion, very little is known about how the ability to perceive one's direction of motion, or heading, from optic flow develops early in life. In this article, we report the results of 3 experiments that tested the abilities of 4-month-old infants to discriminate optic flow patterns simulating different directions of self-motion. The combined results from 2 different experimental paradigms suggest that 4-month-olds discriminate optic flow patterns that simulate only large (> 32°) changes in the direction of the observer's motion through space. This suggests that prior to the onset of locomotion, there are limitations on infants' abilities to process patterns of optic flow related to self-motion.