Abstract
Background. Finding a changing item within a visual scene is difficult. A standard paradigm involves two versions of a scene, an original and one with some item changed (e.g., moved, altered in color, removed, etc.), presented in succession with a blank display between them. Observers may require many seconds to find these changes, yet in most cases the change is eventually found. Does the representation of change develop over the course of the search or is there no representation of change until it is attended? Methods. A priming procedure was incorporated into the standard paradigm. On some trials, a given change was presented for a variable number of cycles (0,1,5), often too few for the observer to find the change. The original change then stopped and a different change was presented until the observer found it. On a later trial, the original change was presented again until the observer found it. If final change-detection time is shorter for longer sub-detection exposure periods, it would indicate that some representation of the change had accrued over the course of the search. Results. Final change detection times were not reliably shorter for any sub-detection exposure periods compared to no exposure periods. Conclusions. There is no evidence of an accruing representation of change, suggesting that change is not represented until the changing item is attended. Alternatively, the priming procedure is insufficiently sensitive to detect an accruing representation. Converging tests of this question using alternate methods are underway.