Abstract
A prominent trend in recent visual cognition research has been the demonstration of impaired visual awareness without attention. An especially striking example is change blindness, wherein surprisingly salient changes can go undetected when the changed objects or regions are unattended. Most such demonstrations induce inattention to the changing object(s) by (1) using displays with at least several objects (yielding other possible foci for attention), and/or (2) using extrinsic disruptions such as eye movements, occluders, or global transients (to directly distract attention and/or to mask the change). Here we explored a type of change blindness in much simpler events, when observers viewed only two objects, with no extrinsic interruptions, and had to fully attend to those objects — reporting everything about them immediately after each 1-second trial. The two objects interacted in an ambiguous dynamic pattern, seen to be either ‘bouncing’ off each other or ‘streaming’ past each other on opposing linear trajectories. We nevertheless observed considerable change blindness: observers failed to notice when the two objects suddenly swapped colors at various points during their motions. This effect was not due to any baseline visual disruption from the motion, however, since observers readily noticed the sudden introduction of new colors into the display during the same events. These results thus demonstrate a type of change blindness in especially simple displays, and suggest that surface feature information is not reliably bound in memory to specific objects, but is rather tied to events as wholes.
(BJS was supported by NSF #0132444)