Visual Perception of Position and Size by Moving and Stationary Observers

Abstract

Visual spatial perception, including perception of objects in their surrounding environment while moving or stationary, is fundamental for any humans to navigate the world. Numerous visual cues provide a moving observer information about the space they navigate and correctly interpreting such information is vital to effectively interact with, or avoid, the elements around them. In Chapter 2, I found that people generally thought an object was more eccentric from straight-ahead than it actually was when judging its position. After being moved laterally, they made additional updating errors when they thought their movement could not be real (i.e., when they were sitting on a fixed chair that they knew could not be moved) compared to when the real movement is possible (i.e., when they were sitting on a moving platform that they knew could move). These updating errors depended on how much they were simulated to move. In Chapter 3, I provide evidence that familiar objects displayed in a 2D scene can be used to judge an object’s size, but not its position (i.e., elevation in the scene). However, it is not enough to derive the correct distance simulated on a screen. In Chapter 4, I demonstrate that when an object displayed in a semi-immersive set up of a 2D scene (with full-size screen, a ground plane continuous with the experimental room, and familiar objects) people can correctly judge its size and absolute distance but not its position. Combined with the results from Chapter 3, people appear to rely on different visual cues when judging size and distance which suggest that the two processes are independent from each other. Incorrectly judged eye height and the height of the horizon in the scene may also influence people’s perception of object size and position differently, but my results were not conclusive and further research is needed. Overall, my research has demonstrated that visual spatial perception is a complex process where people rely not only on different cues for different purposes but are also influenced by whether what they experience could be real or not.