Abstract
Past work has suggested that perception of object distances in natural scenes depends on the environmental surroundings, even when the physical object distance remains constant. The cue bases for such effects remain unclear and are difficult to study systematically in real-world settings, given the challenges in manipulating large environmental features reliably and efficiently. Here, we used rendered scenes and crowdsourced data collection to address these challenges. In 4 experiments involving 452 participants, we investigated the effect of room width and depth on egocentric distance judgments. Targets were placed at distances of 2–37 meters in rendered rooms that varied in width (1.5–40 meters) and depth (6–40 meters). We found large and reliable effects of room width: Average judgments for the farthest targets in a 40-meter-wide room were between 16–33% larger than for the same target distances seen in a 1.5-meter-wide hallway. Egocentric distance cues and focal length were constant across room widths, highlighting the role of environmental context in judging distances in natural scenes. Obscuring the fine-grained ground texture, per se, is not primarily responsible for the width effect, nor does linear perspective play a strong role. However, distance judgments tended to decrease when doors and/or walls obscured more distant regions of the scene. We discuss how environmental features may be used to calibrate relative distance cues for egocentric distance judgments.
Highlights
The capacity of pictures to convey spatial aspects of real environments means that they can be used for planning navigation in environments before visiting them in person
This provides denser gradients of both linear perspective and texture [19, 42–45]. This highlights a second reason why the width effect is surprising: denser cue gradients might be expected to increase distance judgments in the narrow room conditions, but the opposite was true in Experiment 1 – these conditions were reliably associated with smaller distance judgments, with the judgments increasing systematically as the walls to the left and right moved farther away
The main effect of Room indicates that average bias in responses differed between room conditions, while the significant Room x Distance interaction confirms suspicions from Experiment 1 –that the Room conditions are further distinguished by differences in response sensitivity, such that judgments in wider rooms become increasingly larger as target distances increase
Summary
The capacity of pictures to convey spatial aspects of real environments means that they can be used for planning navigation in environments before visiting them in person. Misapprehension of egocentric distances in pictured scenes (i.e., between the observer and objects pictured in the scenes) can lead to navigational errors, poor use of resources, and other negative consequences when used for this purpose. Understanding the factors that impact distance judgments in pictures has practical importance, in addition to the knowledge that pictures can provide about distance processing in humans more generally. Such knowledge can improve computational vision models that aim to reconstruct 3D image properties from pictured scenes [1].
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