Abstract
Sudden isolated changes in visual scenes are easily detected, and typically produce a rapid spontaneous shift of attention towards the location of the change. The current psychophysics study investigates the information observers have regarding the qualitative nature of such a change. Eighteen colored shapes were presented in a circular array for 500ms (frame 1). This display was immediately (with a 0 ISI) followed by a new array (frame 2) in which one item either changed color, shape or both color and shape. Frame two was presented for 500ms, 100ms or 50ms, with no masking. Results: (1) Observers were able to accurately detect and report the location of the changing element independent of the duration frame 2. (2) Observers were unable to report the initial state of the changed element, irrespective of the duration of frame 2. (3) The ability to report the final state of the changed element degraded as a function of decreasing frame 2 duration. Thus on some short frame 2 durations, observers could detect and localize the change without being able to accurately report either the original element or what it changed to. (4) Despite the inability to report the initial state of the changed element, observers could distinguish color changes from shape changes. These results are discussed in the context of change blindness and iconic memory.
Predoctoral NFS fellowship 2005031192 to GPC.