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Carissa M. Lemon, George J. Andersen; Effect of Local Motion Averaging on the Detection of an Impending Collision. Journal of Vision 2013;13(9):705. doi: 10.1167/13.9.705.
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© ARVO (1962-2015); The Authors (2016-present)
Previous research has shown opponent motion mechanisms in area MT average velocities across local regions in the visual field. In addition, research has shown that detecting an impending collision with an approaching object on a linear trajectory is specified by the object maintaining a constant bearing (position in the visual field). Given these findings, we examined whether velocity information adjacent to an approaching object might alter the ability to determine the bearing of the object---as a result of local motion averaging---and reduce collision detection performance. To examine this issue we presented observers with 3D scenes consisting of either a ground plane or a ground plane with objects in the scene that extended vertically from the ground plane. In addition, observers were shown an approaching sphere that was positioned above the ground texture along an arc (±20°). The displays simulated forward observer motion resulting in velocities adjacent to the approaching object when scene objects were present. For half of the trials the sphere was on a collision path with the observer whereas the remaining trials the sphere would pass by the observer. Before the full collision trajectory (7200ms) was shown the trial terminated and observers indicated whether or not the sphere was on a collision path. Two independent variables were manipulated: the presence of adjacent velocities (scene objects present vs. scene objects absent) and display duration (1000ms, 3000ms, and 5000ms). We found that collision detection performance (d’) decreased with the presence of scene objects (F(1, 5)= 8.978, p=0.0302). These results indicate that the ability to determine bearing information for detecting a collision is altered by the presence of adjacent velocities an effect likely due to velocity averaging of opponent motion mechanisms.
Meeting abstract presented at VSS 2013
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