Experiment 2 results (effect of luminance polarity).

(a) Accuracy and (b) reaction time are plotted as a function of number of elements for simple shape (left side of each panel) and random (right side of each panel) configurations, and for same (blue/green symbols) and different (red/purple symbols) luminance poalrity conditions. Top to bottom panels correspond to different simple shape configurations: Equilateral triangle (top panel), square, pentagons and hexagon (bottom panel) configuration. The error bars indicate standard error of the mean (±1 SEM).