Abstract
This study examines what changes to objects disrupt object-based (OB) attention in order to understand the nature of object representation. The experiments reported here used the Egly, Driver, & Rafal (1994) cueing paradigm, in which displays contain 2 objects. Responses to a target that appears at an invalidly cued location are faster when the target is in the object containing the cue than when the target appears equidistant but in a different object; this is the result of OB attention. We used more realistic looking objects and examined what changes occurring between cue and target disrupt OB attention. When OB attention is disrupted, we expect to see space-based (SB) attention: that all targets equidistant from the object are detected equally fast, regardless of which object they are in. We assume that changes that disrupt do so because the representation has changed radically enough that attention is disengaged from the pre-change object representation. Changes between cue and target, which occurred over 3 frames and 150 ms, included morphing of an object to a new identity; disappearance/reappearance of an object; rotation of an object 180 degrees in the picture plane; and translation of an object in a very small circle, maintaining its original orientation. Morphs and disappearance were expected to disrupt object constancy, resulting in SB attention, whereas rotation and translation, being events that should not affect object constancy, were expected to demonstrate OB attention. Translation also controlled for the frame to frame masking found when an object morphs. Results show that morphing, disappearance, and translation all resulted in SB attention, whereas rotation and a no-change condition resulted in OB attention. That translation disrupted OB attention leaves us unclear whether morphing disrupts because of identity change or because of masking effects. Future experiments aim to resolve this issue.