Our everyday visual experience is strongly affected by attention. Visual attention can enhance or prioritize the processing of specific stimuli over the overwhelming number of other sensory inputs by selecting spatial locations (Bisley & Goldberg,
2010; Carrasco,
2011; Chun, Golomb, & Turk-Browne,
2011; Desimone & Duncan,
1995; Egeth & Yantis,
1997; Johnston & Dark,
1986; Kinchla,
1992; Logan,
1996; Pashler, Johnston, & Ruthruff,
2001; Posner,
1980; Posner & Rothbart,
2007), features (Boynton, Ciaramitaro, & Arman,
2006; Maunsell & Treue,
2006; McAdams & Maunsell,
2000; Saenz, Buracas, & Boynton,
2002; Serences & Boynton,
2007; Treue & Martínez Trujillo,
1999), objects (Blaser, Pylyshyn, & Holcombe,
2000), and even time (Lin, Pype, Murray, & Boynton,
2010; Nobre, Allison, & McCarthy,
1998; Swallow & Jiang,
2010). In the past, studies have focused on spatial attention and its derivatives—volitional (endogenous) and reflexive (exogenous) allocation of spatial attention. Feature-based attention, however, has typically been studied using paradigms in which participants voluntarily deploy attention toward a particular visual feature. Attending to a feature such as color or motion in this way produces a global facilitation of processing for stimuli containing that feature throughout the visual field (Liu & Mance,
2011; Sàenz, Buracas, & Boynton,
2003; White & Carrasco,
2011). Given that numerous studies have shown that exogenous cues can enhance sensitivity to visual input at a cued location (Bisley & Goldberg,
2010; Carrasco,
2011; Chun et al.,
2011; Desimone & Duncan,
1995; Egeth & Yantis,
1997; Johnston & Dark,
1986; Kinchla,
1992; Logan,
1996; Pashler et al.,
2001; Posner,
1980; Posner & Rothbart,
2007), we hypothesized that salient features of an exogenous cue might automatically produce feature-based attentional effects that are independent of location-based cuing effects.