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This experiment will attempt to quantify the visual distortion caused by the Poggendorff illusion, using the method of constant stimuli. The computer will present an image of a box with lines emerging from the lower left and upper right corners (see the figure below). The line at the lower left is the standard line. It will be in the same position throughout the experiment. The line at the upper right is a comparison line, but its position will change throughout the experiment. You will judge whether or not the comparison line is too high or too low relative to a point (i.e., see "True Connection Point" in figure below) where the standard and comparison lines would appear collinear.