There is an expansive literature on selective attention to objects using procedures introduced by Egly, Driver, and Rafal (
1994) that shows that objects in a display modulates the allocation of attention (e.g., Atchley & Kramer,
2001; Haimson & Behrmann,
2001; Marino & Scholl,
2005; Moore & Fulton,
2005; Moore, Yantis, & Vaughn,
1998; Robertson & Kim,
1999; Scholl,
2001; Vecera,
1994). Egly, Driver, et al. examined attentional selection by presenting two rectangles of equal length and distance from each other. They combined this stimulus with a Posner cuing task (Posner, Snyder, & Davidson,
1980) in which a cue predicted the location where a subsequent target would most likely appear. In a predictive cuing procedure, Egly, Driver, et al. cued one end of one of the rectangles and measured participants' reaction time (RT) to detect a target that appeared 300 ms later either at the cued location, at an uncued location within the same rectangle, or at an equally distant uncued location within the uncued rectangle. As expected, RTs to cued locations were faster than those to uncued locations. The novel finding was from trials when targets appeared at uncued locations (invalid trials): RTs were faster when the target appeared in the cued rectangle (invalid-within object trials) than in the uncued rectangle (invalid-between objects trials) (
Figure 1). Because the distances between the cued (valid) and each uncued (invalid) locations were spatially equivalent, the RT advantage for within compared to between rectangle conditions has been referred to as an object-based attention effect.
1 This procedure has been widely adopted to explore the roles of exogenous vs. endogenous attention (e.g., Jordan & Tipper,
1999; Macquistan,
1997) and hemispheric asymmetries (e.g., Egly, Rafal, Driver, & Starrveldt,
1994) among numerous other questions. However, given the above discussion on holes (namely, that all enclosed regions need not be objects), the “object” in object-based attention can be difficult to systematically define.