Abstract.
Self-movement through an environment generates optic flow, a potential source of heading information. But it is not certain that optic flow is sufficient to support navigation, particularly navigation along complex, multi-legged paths. To address this question, we studied human participants who navigated synthetic environments with and without salient optic flow.

Participants used a keyboard to control realistic simulation of self-movement through computer-rendered, synthetic environments. Because these enviroments comprised series of identically textured visual corridors and intersections, participants had to build up some mental representation of the environment in order to perform. The impact of optic flow on learning was examined in two experiments.

In Experiment 1, participants learned to navigate multiple T-junction mazes with and without accompanying optic flow. Optic flow promoted faster learning, mainly by preventing disorientation and backtracking in the maze.

In Experiment 2, participants found their way around a virtual city-block environment, experiencing two different kinds of optic flow as they went. By varying the rate at which the display was updated, we created flow that was either fluid or choppy. Here, fluid optic flow (as compared with choppy optic flow) enabled participants to locate a remembered target position more accurately.

Our experiments showed no gender-related differences, either in participants' performance or in the way that they exploited available information.

When other cues are unavailable, optic flow can significantly aid human wayfinding. Among other things, optic flow facilitates path integration, which involves updating a mental representation of place by coming by trajectories of previously travelled paths.

Participants' path integration was reminiscent of analogous behavior that has been observed in desert ants and other creatures. However striking the parallel, though, it is important to remember that humans are not ants. For example, in our species, alternative navigation strategies can coexist and remain available to be used as needed.