The relative contributions of luminance contrast and task demands on saccade target selection

Luminance contrast and spatial frequency have a strong effect on when saccades are initiated. In this study, we ask to what extent the internal contrast response determines where saccades are directed to. Observers signalled, with a manual button press, which of two patterns was of higher (Experiment 1) or lower (Experiment 2) contrast. Even though the visual stimuli were identical in both experiments, the pattern of first fixated items was very different. Saccade target selection largely reflected the task instructions, suggesting that luminance contrast can be used to rapidly and effectively guide the eyes to task-relevant information.