Visual control of steering through multiple waypoints.

Effective locomotion often requires the ability to navigate within complex environments at speed, moving smoothly through multiple waypoints while avoiding obstacles. If actors consider only one waypoint at a time, they may be forced to make jerky steering adjustments, collide with obstacles, or miss waypoints altogether. Findings from previous studies suggest that humans do use information from beyond the most immediate waypoint but leave open questions about how such information is used to control steering and speed of self-motion. The present study was designed to test three hypotheses about how humans anticipate multiple upcoming waypoints. Subjects performed a simulated drone-flying task in which they used a game controller to steer through a series of three gates: Gates 0 and 1 that were centered on the longitudinal axis and separated by a fixed distance, and Gate 2 at a distance, angle, and orientation that was manipulated across trials. In Experiment 1, when the drone was programmed to simulate a more sluggish vehicle, subjects initially veered away from Gate 1 before turning back, setting up a smoother trajectory through Gate 1 toward Gate 2. Trajectories between Gates 0 and 1 varied with the angle and distance (but not orientation) of Gate 2. In Experiment 2, when the drone was more agile, subjects flew more directly toward Gate 1 regardless of the position of Gate 2, rapidly decelerating and turning sharply toward Gate 2 at the last moment. Taken together, the results support the hypothesis that actors are attuned to their action capabilities and guide their movements so as to maintain the ability to successfully steer through upcoming waypoints within those capabilities. Such behavior is consistent with the more general theory of affordance-based control.