Shifting Eyes and Thinking Hard Keep Us in Our Lanes

Abstract

Previous research suggests that performing a secondary, non-visual task while driving (such as conversing on a hands-free cell phone) may lead to a reduction in lateral vehicle movement. A plausible explanation for this counterintuitive finding involves scanning differences under differing cognitive load. The goal of this study was to dissociate the effects of visual scanning and workload on lateral vehicle control. Eighteen participants drove nine, five minute scenarios in a fixed based driving simulator under varying workload and guided fixation conditions. Consistent with previous finding, increased secondary task load decreased lateral vehicle movement. The active movement of eyes also led to reductions in lateral vehicle movement but only when drivers were concurrently performing one of the secondary tasks. These results suggest that scanning differences under cognitive load cannot fully account for observed reductions in lateral vehicle movement and that multiple interrelated factors likely contribute to lateral vehicle movement.