How the Type of Visual Feedback Affects Actions of Human operators: The Case of Virtual Stick Balancing

Maintaining vertical position of an inverted pendulum is a simple balancing task, which is widely used to study human control behavior. Yet, much about this behavior remains poorly understood even in the context of simple virtual tasks. The purpose of this study was to investigate whether the control behavior of human operators depends on the type of visual feedback from the controlled system. We analyze the experimental data on human stick balancing on a computer screen. The previous studies reported detailed analysis of the task performance of human operators observing only the angular deviation of the stick from the vertical. In this study we augmented the information supplied to the operator by linear displacement of the upper tip of the stick from the reference point. This additional information was suggested to improve the performance of the operators. Surprisingly, the subjects not only exhibited better performance, but also supposedly employed structurally different control mechanisms in the linear displacement condition. The found results may have potential implications both for fundamental research aimed at investigating the basic properties of human control, and applied research on human factors.