The role of spatial attention in nonconscious processing: a comparison of face and nonface stimuli.

Recent findings from the masked priming paradigm have revealed a surprising influence of higher-level cognitive systems (i.e., attention) on nonconscious cognitive processes. These data have effectively undermined the long-standing assumption in cognitive science that nonconscious processes are carried out independently of attention and have quickly led to the opposite view that attention is a prerequisite for nonconscious processes. Here we present evidence for a middle position by showing that the dependence of nonconscious processes on attention varies with the type of information to be processed. Specifically, we found that nonconsciously perceived faces engaged cognitive processes regardless of attention, whereas nonface stimuli engaged cognitive processes only when attended. These qualitatively different patterns suggest two distinct processing routes: one that is modulated by visual attention and one that is not.