Age Related Decrements in Steering Control: The Effects of Landmark and Optical Flow Information

This study examined age related decrements in the use of optical flow and landmark information for the control of steering. Older and younger drivers viewed computer generated displays simulating vehicle motion through a random dot ground plane scene. The horizontal position of the driver was perturbed according a sum of sines function and the driver had to keep steering straight (resembling the task of steering a car on a gusty day). On half the trials, landmark information was presented by color coding one of the dots on the ground plane. Overall, older drivers showed greater steering error magnitude (RMS error) than younger drivers. Unlike the younger drivers, the older drivers showed no reduction in steering errors when landmark information was present. These results suggest that older drivers are more reliant on optical flow information for controlling a vehicle and have a reduced ability to use alternative sources of information, such as landmarks, for steering control.