Abstract
Accurate information about the spatial location of objects during visual search influences the allocation of processing capacity to task-relevant and task-irrelevant information. According to Load theory (Lavie, 1995), processing capacity is allocated to stimuli presented at task-relevant locations and any remaining capacity spills-over to stimuli at task-irrelevant locations. This scheme implicitly assumes that stimulus location information is accurate and available before the allocation of processing capacity. However, performance in these tasks is explained by an instantiation of the Theory of Visual Attention (TVA, Bundesen, 1990) that assumes parallel computation of location information and stimulus identity (Kyllingsbæk et al., 2014; Kyllingsbæk, 2015). If true, then manipulations that improve the accuracy of the spatial information about the locations of task-relevant and task-irrelevant stimuli should serve to reduce the extent to which irrelevant information interferes with performance. We tested this prediction using an unspeeded hybrid flanker-visual search task (Lavie & Cox, 1997; Kyllingsbæk et al., 2014) in which information about stimulus locations was provided using placeholders. Over the course of 6 sessions (3456 trials), participants (n=6) reported whether the search target was an X or Z while ignoring congruent/incongruent stimuli at the flanker locations presented outside the search display. Consistent with the prediction, there was no effect of flanker congruency on target discrimination (F (1,5)=.897, p=.387). A direct comparison to the results of an identical task conducted without placeholders (Kyllinsbæk et al., 2014) revealed a significant interaction (F(1,10)=5.945, p=.035), such that when placeholders were present, the flankers did not interfere with performance, but when placeholders were absent, flanker interference was observed. These findings are consistent with the notion that information about stimulus location and identity are processed in parallel and together influence the efficient allocation of perceptual processing capacity.
Meeting abstract presented at VSS 2016