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Carissa Lemon, George Andersen; Proximity of adjacent velocities and collision detection. Journal of Vision 2015;15(12):1010. doi: 10.1167/15.12.1010.
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© 2017 Association for Research in Vision and Ophthalmology.
Previous research has demonstrated that the detection of an impending collision on a linear trajectory is specified by an object maintaining constant bearing (position in the visual field). Additionally, velocity information adjacent to an approaching object has been shown to alter the ability to determine bearing information. In the present study we examined the effect of proximity of adjacent velocity on collision detection judgments. Observers were presented with 3D scenes consisting of either a ground plane or with a ground plane with objects in the scene that extended vertically from the ground. These scene objects were presented on either both sides of the scene or on only one the side scene (the side opposing the approaching object). Two independent variables were manipulated: the presence of adjacent velocities (scene objects absent, scene objects present on both sides, and scene objects present on only one side), and display duration (1000ms and 5000ms). We found that sensitivity to detect a collision (d’) decreased with display duration (F(1, 7)= 101.194, p< .001) and with the presence of scene objects (F(2, 7)= 5.744, p=0.015). Post-hoc analysis indicated scene objects on both sides compared to scene objects on only one side did not differ significantly from one another but scene objects absent differed significantly from scene objects present on both sides. These results demonstrate that the effect of adjacent velocities found in previous research was not due to the mere presence of objects within the scene and that proximity of adjacent velocities is the important factor. This provides further evidence suggesting opponent motion mechanisms in area MT average velocities across local regions in the visual field.
Meeting abstract presented at VSS 2015
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