The path of least persistence: object status mediates visual updating.

On what basis does the visual system use recently sampled information to update existing representations of the world? One possibility is that representations are updated through an image-based point-for-point replacement process. An alternative possibility is that representations are updated on the basis of perceptually organized units that reflect objects in the scene rather than locations within the visual field. We report a new effect involving a modulation of visible persistence that seems to support this alternative possibility. In particular, we show that a moving stimulus leaves a visible trace of itself when it undergoes an abrupt and transient change in size but does not do so when the stimulus does not change. Further we show that this effect is substantially reduced when a scene-based reason for the abrupt change in size is provided (i.e., the object is shown to be passing behind an occluding surface that has a very small window in it through which the stimulus shows briefly). We suggest that the visible persistence in the face of change reflects a disruption of the normal updating process which is object-based and disrupted because of the discontinuity of the object. Providing a scene-based reason for the discontinuity allows the object representation to be maintained, and thus does not result in a disruption of the updating process.