Abstract
Past work established a robust effect of room width on egocentric distance judgments - wider rooms elicit larger judgments than narrower rooms. Investigation into the factors involved found that objects or boundaries near the target contribute substantially to this room width effect. Experiments 1 and 2 investigated if the equidistance tendency is responsible. Both experiments utilized computer-rendered indoor scenes measuring 40 x 40 m and participants gave a numerical distance judgment to a target (orange cone). Experiment 1 (n=96) manipulated the proximity and placement of a 1.0 x 0.20 m column to the target. The equidistance tendency predicts shorter distance judgments when columns are closer to and in front of the target and larger judgments when columns are farther from and behind the target. Results showed no effect of column placement in any proximity (p=0.88) or directional location (p=0.89). To increase the likelihood of detecting an influence of the equidistance tendency, Experiment 2 (n=99) added a second column and increased the columns’ size (1.5 x 0.50 m), placing them at a constant visual angle of 1.17 degrees from the target either in front of, behind, or directly to the side. Another condition placed a low “curb” on the floor to test if a boundary was necessary to elicit the room width effect. Results showed no differences between the column conditions (all p’s > 0.97), ruling out the equidistance tendency as a mechanism. Columns in front of or behind the target yielded shorter judgments than the wide room without columns (both p’s<0.04), but not as short as the narrow room (both p’s<0.0004); the curb condition was equivalent to the wide room (p=0.97). This indicates that objects in proximity to the target decrease distance judgments more than boundaries, but further research is required to refine the mechanism behind the room width effect.