Lateral interactions between targets and flankers in low-level vision depend on attention to the flankers

Detection of an oriented visual target can be facilitated by collinear visu al flankers. Such lateral interactions are thought to reflect integrative p rocesses in low-level vision. In past studies, the flankers were task-irrel evant, and were typically assumed to be unattended. Here we manipulated att ention to the flankers directly, by requiring observers to judge the relati ve alignment of two flankers while ignoring a second flanker-pair. Under id entical stimulus conditions, attended flankers produced typical lateral int eractions, but ignored flankers did not. These data show that lateral inter actions can depend on attention to the flanking context, revealing the func tional consequences of attentional modulation in low-level vision.