Purchase this article with an account.
Megan L Meyer, Thomas F Shipley; Perception of curved apparent motion paths. Journal of Vision 2003;3(9):785. doi: 10.1167/3.9.785.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
In two-frame apparent motion displays observers typically see motion along a straight path. Curved paths have been demonstrated for some specific stimulus configurations that may reflect knowledge of object motions; e.g., human limbs appear to move on curved paths when shown for long durations. Here we consider the potential role of a general solidity constraint (objects generally do not pass through one another) on the path of apparent motion.
We investigated the effects of the location and shape of a barrier in apparent motion displays with simple geometric forms. When a barrier was directly between the locations of the moving object, the shape of the barrier (triangle or circle) had little effect and subjects reported straight paths for most of the trials. In contrast, when only a portion of the barrier was between the locations, reports of curved paths increased with increases in SOA (for the round barrier the majority of paths were curved).
When barrier shape varied (triangle, pentagon, and circle), reports of curved paths increased as a function SOA with the greatest number of curved paths reported for the circle. The probability of reporting a curved path was a direct function of the turning angle of the barrier (lowest for circle and highest for triangle).
To see if motion in depth is also affected by the presence of a barrier, the second experiment was replicated with photographs of three-dimensional geometric wooden blocks (e.g., a cylinder). Again, the shape of the barrier influenced the perceived path with the majority of subjects reporting a curved path for the cylinder at long SOAs.
These findings suggest that the visual system constructs paths of motion where objects do not pass though one another. This tendency is limited, however, paths that avoid obstacles cannot be arbitrary shapes, such paths seem to be restricted to simple curves with low curvature.
This PDF is available to Subscribers Only