Abstract
Object file theory provides a framework for object representations and is demonstrated by an object-specific preview benefit (OSPB) (Kahneman, Treisman & Gibbs, 1992). This framework supports object-based attention by showing that a priming effect for object identity travels with the object in which information initially appeared. The present study explores OPSB effects during Multiple Object Tracking (MOT).
In Experiment 1, four identical circles moved unpredictably in MOT and a preview letter appeared in one circle during the trial. At the end of the trial a test letter appeared and subjects had to indicate whether or not the test letter matched the preview letter (SOAs between preview and test letters varied at 1, 2, and 4 seconds). Subjects' reaction times in matching letter conditions (i.e., same preview object versus different object) showed a significant OSPB effect of 90 ms (p=.000) for the 1-second SOAs, and this benefit was reduced with longer SOAs. In Experiment 2, two preview letters were presented in two objects. The results exhibited similar patterns as Experiment 1 but with a smaller preview effect (47 ms; p=.013).
To explore the effect of explicit tracking in Experiment 3, two preview letters were shown within two circles prior to object movement (constant 4-second SOAs). In block 1, no explicit tracking was required. In block 2, subjects tracked and identified the circles that had contained letters in addition to judging whether a test letter was one of the preview letters. There was no OSPB effect in the nontracking condition (replicating the 4-second SOA results in Experiment 2), but there was a significant preview effect of 94 ms (p=.000) in the explicit tracking condition.
These findings replicate the original OSPB experiments but using the dynamic MOT framework and suggest that explicitly tracking objects extends the OSPB effect.