Visual processing of the impending collision of a looming object: Time to collision revisited

As an object approaches an observer's eye, the optical variable tau, defined as the inverse relative expansion rate of the object's image on the retina (D. N. Lee, 1976), approximates the time to collision (TTC). Many studies have provided support that human observers use TTC, but evidence for the exclusive use of TTC generated by tau remains inconclusive. In the present study, observers were presented with a visual display of two sequentially …