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Abstract

Several sources of information have been proposed for the perception of heading. Here, we independently varied two such sources (optic flow and viewing direction) to examine the influence of perceived heading on driving.
Participants were asked to stay in the middle of a straight road while driving through a snowstorm in a simulated, naturalistic environment. Subjects steered with a forced-feedback steering wheel in front of a large cylindrical screen. The flow field was varied by translating the snow field perpendicularly to the road, producing a second focus of expansion (FOE) with an offset of 15°, 30°, or 45°. The perceived direction was altered by changing the viewing direction 5°, 10°, or 15°. The onset time, direction, and magnitude of the two disturbances were pseudo-randomly ordered.
The translating snow field caused participants to steer towards the FOE of the snow, resulting in a significant lateral displacement on the road. This might be explained by induced motion. Specifically, the motion of the snow might have been misperceived as a translation of the road. On the other hand, changes in viewing direction resulted in subjects steering towards the road's new vantage point. While the effect of snow persisted over repeated exposures, the viewing-direction effect attenuated.