Spatial Asymmetries in the Fl Anker-congruency Effect: Attentional Scanning Is Biased by Fl Anker Orientation

If targets are fl anked by congruent or incongruent distractors, performance is facilitated or impaired, respectively. Prior studies revealed that, with normal letters, this fl anker effect is more pronounced with leftthan with right-side fl ankers. The present study shows that the left-side bias is eliminated if the fl ankers (but not the target) are mirrored (Experiment 1). If the orientation of the stimulus string varies randomly from trial to trial, the asymmetry depends on orientation: Normal letters produce a left-side bias while mirrored letters tend to produce a right-side bias (Experiment 2). Interestingly, these orientation-specifi c biases are observed only in trials where fl anker orientation is repeated but not after a switch in orientation. These results suggest that the asymmetry effect does not refl ect target-related processing or on-line selection strategies. Rather, processing fl ankers of a particular orientation seems to bias the cognitive system to scan subsequent fl ankers in a particular direction.