In this experiment, you will see three comparisons: (1) The standard Muller-Lyer with fins and lines, (2) The standard Muller-Lyer with longer fins, and (3) The standard Muller-Lyer with shorter fins.

The experiment starts by loading the basic images of the three conditions. Then a window pops up asking you to type in your name and then click OK. After the window disappears, there is a 3 second wait while just the inward Muller-Lyer with fins and lines is displayed on the screen. Then the outward Muller-Lyer is displayed on the right and you are ready to begin.

For each of the Muller-Lyer conditions, the outward form will be on the right and the inward form will be on the left. The outward form will be the standard of comparison and won't change during a trial (but will change between trials).

Your task is to adjust the inward form until the length of line from tip to tip matches the length of the line in the outward standard.

You adjust the left side by moving your mouse up and down over the words "MUCH LONGER", "LONGER", "SHORTER", OR "MUCH SHORTER". DON'T CLICK ON THE WORDS.

Moving the mouse up and down over MUCH SHORTER makes the right side shorter faster. SHORTER is for fine adjustments. MUCH LONGER makes the right side longer faster. LONGER is for fine adjustments.

When you believe the left line and right line are the same length CLICK on the DONE button and you will be presented with the next trial. There are 30 trials in all. The textbox above the DONE button tells you what trial you are on.

At the end of 30 trials, you will click on the SUBMIT button to be shown your results.

When you have read and understood these instructions, Please click on the word START below, to begin.