Modulation of object-based attention by spatial focus under endogenous and exogenous orienting.

In R. Egly, J. Driver, and R. D. Rafalʹs (1994) influential double-rectangle spatialcuing Aparadigm, exogenous cues consistently induce object-based attention, whereas Aendogenous cues generally induce space-based attention. This difference suggests an Ainterdependency between mode of orienting (endogenous vs exogenous) and mode of selection A(object based vs space based). However, mode of orienting is generally confounded with Ainitial focus of attention: Endogenous orienting begins with attention focused on a Acentral cue, whereas exogenous orienting begins with attention widely spread. In this Astudy, an attentionalfocusing hypothesis is examined and supported by experiments Ashowing that for both endogenous and exogenous cuing, object-based effects are obtained Aunder conditions that encourage spread attention, but they are attenuated under Aconditions that encourage focused attention. General implications for object-based Aattention are discussed.