The Role Of Surface Feature Cues In Object Persistence

In a dynamic visual environment, the visual targets (usually visual objects) are always moving or changing. The visual system has to deal with this characteristic of environment to maintain the consistency and continuity of object representations so that the stable visual consciousness can be persisted. This ordinary visual function is termed object persistence. The most influential framework in the aspect of object persistence is the object file theory (Kahneman, Treisman & Gibbs,1992). This theory claims that spatiotemporal information, rather than surface feature information, is the key cues in object persistence. A recent study found that when two objects with different features are previewed and then disappeared for one second, the participants could not establish the object correspondence basing on the surface feature cues (Mitroff & Alvarez,2007). However, the spatiotemporal discontinuity involved in the study may mask the effect of surface feature consistency. To isolate the role of surface feature in object persistence, we must create a special kind of visual scene that makes the spatiotemporal cues ambiguous. Therefore, the present study designed a new "tunnel" stimulus. In the tunnel objects can move in two horizontal entrances and out of two vertical exits randomly, which allow participants consulted only surface feature information to persist the continuous objects. Based on this design, the present study conducted two series of experiments, each consisting of four experiments.In the Series 1, the tunnel stimulus was used to test the role of color (Exp.1), shape (Exp.2), and topology (Exp.3) in object persistence. The results of all the three experiments found that the consistency on one feature dimension was informative enough to compute the object correspondence. Exp.4 further explored multi-dimensional features and found that the consistency on such features could produce a larger effect size of OSPB effect.The Series 2 altered the tunnel to introduce certain corresponding relations between entrances and exits so that the spatiotemporal cues were unambiguous. Exp.5 replicated the role of spatiotemporal cues in object persistence. Exp.6 found a consolidating effect when the spatiotemporal and surface feature cues were matched. Exp.7 and Exp.8 explored the situation where the two cues were conflicted; the results suggest that neither cue would be dominant in object persistence and that the two cues affected the persistence independently.This study demonstrated, first in a system way, that the surface feature cues could achieve object persistence independently, which revised the original version of the object file theory. Moreover, the experimental method (especially the tunnel stimulus) was a new valid way to control the spatiotemporal cues of moving objects, which was expected to be used in the future researches.