Spatial attention and conscious perception: interactions and dissociations between and within endogenous and exogenous processes

A current controversy exists about the relationship between spatial attention and conscious perception. While some authors propose that these phenomena are intimately related (Bartolomeo, 2008; Chun & Marois, 2002; O'Regan & Noë, 2001; Posner, 1994), others report dissociations between them (Kentridge et al., 1999; Koch & Tsuchiya, 2007; Wyart & Tallon-Baudry, 2008). However, spatial attention is not a unitary mechanism, and it is possible that not all forms of attention dissociate from conscious perception. In the present study we used a paradigm in which endogenous and exogenous forms of attention are orthogonally manipulated in order to investigate their relation with conscious perception within the same design. By analyzing two different cue-related components, our results demonstrated that while endogenous attention was electrophysiologically dissociated from conscious perception, exogenous attention was not, consistent with the hypothesis that exogenous attention is an important antecedent of our conscious experience. Our results support previous claims of dissociations between some forms of spatial attention and conscious perception, but also highlight the importance of exogenous orienting on the selection of information for conscious access.