Thank you for participating in this experiment! You will be looking at pairs of checkerboards consisting of squares with random lightnesses--they will appear to be square patches of blacks, whites, and shades of gray. Most of the patches on the screen will be drawn from the same range of lightnesses. However, for each pair of checkerboards, one of the checkerboards will have a number of patches drawn from a larger range of values. The exact configuration of those patches will be different across different experimental conditions, and the experimenter will explain these configurations to you before you begin. Your task, for each pair of checkerboards, is to pick the checkerboard that has these patches drawn from a larger range of values. The trials are not timed, so you do not have to rush through them. Each blocks consists of 6 experimental conditions of 100 trials each. You may pause at any time if you need a break. The computer will beep if your selection on the last trial was incorrect, and will tell you when each block and condition begins and ends. If you have any questions, please do not hesitate to ask. Thanks again!