Abstract
In natural vision, although moving objects are often partially or fully occluded, we are able to maintain coherent representations of them and their locations. The form of an object can influence judgments regarding its motion path, especially for the case of biological motion (Shiffrar and Freyd, 1990). Moreover, these effects can be dependent on temporal factors such as exposure duration. Here, we used an occlusion paradigm to investigate how the amount of motion information affects predictions of object movements. We were further interested whether these predictions would also be affected by the biologicalness of the object. The object presented was either biological (hand) or non-biological (oval). The pre-occlusion exposure time (prime duration) was either 100, 500, or 1000 ms, followed by a 500 ms occlusion period. When the object reappeared, the motion continued at an earlier frame (-350, -100, -20 ms), at the correct frame, or at a later frame (+20, +100, +350 ms). Participants were asked to judge whether or not the continuation after occlusion was too late. For both object types, there was a significant difference in the psychophysical curves for 100 and 1000 ms prime durations: when very little motion information was available (100 ms) before occlusion, it is harder to make predictions about the movement of the object. For the hand (biological) object only, prediction performance of biological motion trajectories was also significantly different for the 500 and 1000 ms durations. These data suggest that given sufficient time, hence more information, the visual system can be influenced by high-level constraints such as knowledge of how biological objects move in making predictions about object movement. These data are consistent with Bayesian models of cue integration in perception.
Meeting abstract presented at VSS 2015