The role of spatial attention in visual word processing has long concerned researchers. This research has focused predominately on questions concerning selective attention (e.g., the debate over early vs. late selection; e.g., Brown, Gore, & Carr, 2002;Risko, Stolz, & Besner, 2005), for which words functioned as convenient stimuli (see Lachter, Forster, & Ruthruff, 2004, for a review). In contrast, questions regarding how attention influences visual word processing have received much less consideration. It is to these questions that we turned in the present investigation.
Spatial AttentionVisual spatial attention allows individuals to select specific regions of the visual field for preferential processing (see Carrasco, 2006;Posner & Peterson, 1990, for reviews). The present investigation was concerned with covert spatial attention (i.e., shifts of spatial attention without eye movements). Attending to a location where a target appears has been demonstrated to improve performance across a number of different tasks (see, e.g., Carrasco, 2006).The most popular way to measure the influence of spatial attention is in the context of the spatial cuing paradigm (Posner, 1980). In this paradigm, a target is preceded by a spatial cue indicating the upcoming target's location (i.e., a valid trial) or a nontarget location (i.e., an invalid trial). Response times are typically faster on valid than on invalid trials (Posner, 1980). This cuing effect can be taken as an index of the influence of spatial attention on performance. For example, if spatial attention has no influence on processing, then no cuing effect should be observed.To understand the role of spatial attention in visual word processing, previous research has combined the cue validity manipulation with different word-processing tasks (Besner, Risko, & Sklair, 2005;Ducrot & Grainger, 2007;Hardyck, Chiarello, Dronkers, & Simpson, 1985;Lindell & Nicholls, 2003;McCann, Folk, & Johnston, 1992;Nicholls & Wood, 1998 ) demonstrated a robust cuing effect in lexical decision, suggesting that spatial attention influences word processing in some manner. Nicholls and Wood (1998) and Nicholls et al. also demonstrated a robust cuing effect in a reading aloud task. To better understand the nature of this cuing effect, the cue validity manipulation has been combined with manipulations that influence particular subcomponents of word processing. The nature of the joint effects of these factors can then be used to infer which reading processes are influenced by spatial attention (see, e.g., Sternberg, 1969). McCann et al. (1992) combined a manipulation of cue validity with manipulations of word frequency and lexicality in the context of a lexical decision task. The effects of cue validity were additive with both of these factors. Specifically, the size of the cuing effect was equivalent for high-and low-frequency words and equivalent for words and nonwords. Nicholls and Wood (1998), Nicholls et al.
989© One major idea about spatial attention is that it serves to modulate crosstalk ...