Abstract
When the image of a moving object undergoes an abrupt change, such as suddenly becoming 10% of its original size for one frame of motion, it can result in a phenomenon that we have called change-related persistence. The image of the changed stimulus visibly persists causing the perception of two simultaneously present objects, the changed object and the post-change original-sized object (Moore & Enns, 2004). We offered an explanation in terms of an object-mediated representational updating process. The changes were too extreme for the perceptual system to tolerate as having occurred within a single object. So a new object representation was established. As a distinct object it was not overwritten by later information associated with the original object and therefore persisted. Consistent with this account, providing a scene-based reason for why the image of the object changed, like depicting it as moving behind an occluding surface with a small window through which 10% of the original stimulus is revealed as it passes, reduced change-related persistence (Moore, Mordkoff, & Enns, in press). A challenge to the object-mediated updating account, however, is that the perception of apparent motion between two stimuli tends to be robust across large differences in stimulus attributes like shape and color, suggesting that these differences are not sufficient to elicit the establishment of a new object representation (e.g., Kolers & Pomerantz, 1971). Why the difference across the two situations? We replicated the robustness of two-frame apparent motion over figural changes that maintain approximate size. Apparent motion across large changes in size, however, was not as robust. In addition, the fact that only two frames of motion are used in most apparent motion studies, whereas many frames of motion preceded the change in the change-related persistence studies may also play an important role in the apparent conflict.