How is human gait controlled by vision?

In his seminal article, Gibson (1958/this issue) laid the foundation for understanding the visuomotor transformations necessary for adaptive locomotor behavior. In this article, I review the work on visual control of locomotion done in our lab in Waterloo and discuss some new experiments. The major findings are put forward as three new postulates. Postulate 1: Visual exteroceptive information about the environment is used in a sampled, feed-forward mode to control locomotion. Postulate 2: Visual exproprioceptive information about the posture and movement of the lower limb is used in a sampled, online mode to control the swing phase trajectory. Postulate 3: Visual exproprioceptive information about self-motion is used in a sampled, online mode to control locomotion. Our results in most cases provide empirical support for the many insightful postulates of Gibson, in some cases amplify his statements, and in a few cases add to our understanding of how we get about by vision.