Chris Sims, Postdoctoral Research Fellow, Center for Visual Science, University of Rochester

Chris Sims, Postdoctoral Research Fellow, Center for Visual Science, University of Rochester



Human behavior in natural tasks consists of an intricately coordinated dance of cognitive, perceptual, and motor activities. While much research has progressed in understanding the nature of cognitive, perceptual, or motor processing in isolation or in highly constrained settings, few studies have sought to examine how these systems are coordinated in the context of executing complex behavior. In the research project I will describe, I examined how eye movements are controlled when the cognitive and motor systems place competing demands on vision. Such a scenario occurs when gaze must be distributed among two basic, yet important visual activities: using vision for closed-loop motor control, and using vision for information acquisition to support the planning of future actions. Previous research has suggested that in the course of visually-guided reaching movements, the eye and hand are "yoked", or linked in a non-adaptive manner. In this work we report an experiment that manipulated the demands that a task placed on the motor and visual systems, and then examined in detail the resulting changes in visuomotor coordination. 

In contrast to the yoking hypothesis, it was found that subjects adapted their visuomotor coordination to the changing task demands. To further understand the nature of this behavior, an "ideal actor" model was developed to predict the optimal coordination of vision and motor control. Using this model, human performance is shown to reflect a near-optimal response to the varying costs imposed by the experimental manipulations. These results offer new insight into the flexibility of human behavior, but pose a serious challenge to existing models of cognitive control in interactive tasks.

 Adaptive allocation of vision under competing task demands