Attentional Capture by Context Cues, Not Inhibition of Cue Singletons, Explains Same Location Costs

Recent attentional capture studies with the spatial cueing paradigm often found that target-dissimilar precues resulted in longer RTs on valid than invalid cue trials. These same location costs were accompanied by a contralateral positivity over posterior electrodes from 200 to 300 ms, similar to a P-D component. Same location costs and the P-D have been linked to the inhibition of cues with a unique feature (singleton cues) that do not match the target feature. In some studies reporting same location costs, the cue was surrounded by other cues (i.e., the context cues) that matched the physical or relative feature of the target. We hypothesized that the context cues might have captured attention and might have elicited data patterns that mimicked the inhibitory effects. To disentangle inhibition of the singleton cue from capture by the context cues. we added gray cues to the cue array, which we considered neutral because gray matched neither the target nor the nontarget color. In four experiments, the results consistently showed that the context cues in the nonmatching cue condition captured attention, as reflected in shorter RTs compared to neutral cues and a substantial N2pc to lateralized context cues. By contrast, the evidence for inhibition of the singleton cue was rather weak. Therefore, same location costs and lateralized positivity in the event-related potential of participants in several recent studies probably reflected attentional capture by the context cues, not inhibition of the singleton cue.