Critical Roles for Distance, Task, and Motion in Space Perception: Initial Conceptual Framework and Practical Implications

Objective: A conceptual framework of visual space perception is proposed. Background: Prior studies suggest that the processes underlying space perception depend on viewing distance, the nature of a task, and the presence and nature of motion. Method: Evidence from neuropsychological, neuroimaging, and behavioral studies is reviewed. Results: A preliminary conceptual framework of space perception is proposed in which three critical factors of distance, task, and motion represent different dimensions. Different locations within the framework represent the involvement of different underlying processes. At one extreme, indirect perception underlies a stationary observer's perceptual judgments of stationary objects in far space. At the other extreme, direct perception underlies a moving observer's actions involving moving objects in near space. Between these extremes, both processes are utilized and allow for flexibility in human performance. Conclusions: Prior studies of space perception should be reevaluated based on viewing distances employed, the nature of the tasks, and the presence and nature of motion. Future studies of space perception should manipulate these variables. Application: If, as proposed by the framework, observers use different underlying mechanisms to perceive near and far spaces and to perform different types of tasks, it becomes important to identify the limits of such mechanisms and to design technologies to accommodate those limits. For example, collision-avoidance warning systems may have to utilize different criteria for providing warnings at near versus far headways. Further study of the proposed framework will help improve the design of such technologies.