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### THE PROCEDURE and INSTRUCTIONS

(You may want to print this page for reference during the experiment). There are two types of trials in the experiment. The first type of trial is where the comparison line (bottom line) will appear at the beginning of the trial to be either longer or equal to the standard line (top line). Let's discuss this one first. By pressing a sequence of buttons over two phases, you are going to make the comparison line decrease in length until it appears shorter than the standard line--this is called a descending type of trial:

### DESCENDING TYPE OF TRIAL

#### Phase one of descending type of trial

In the first phase, your task will be to decide if the comparison line is longer or equal to the standard (see figure below):

If the comparison (bottom) line looks longer than the standard, hit the Longer button. If the comparison line looks equal to the standard line, hit the Equal button. If you hit the Longer button, you will then be presented with a new comparison line that will either be equal to or smaller than the last comparison line. Again, you will need to decide: is the comparison line Longer than or Equal to the standard line? When you hit the Equal button, this will start the second phase of the trial.

#### Phase two of descending type of trial

After you press the Equal button in phase one, you will be presented with a new comparison line (see figure below). In this phase, your task will be to decide if the comparison line is equal to or shorter than the standard:

If the comparison (bottom) line looks equal to the standard line, hit the Equal button. If the comparison line looks shorter to the standard line, hit the Shorter button. If you hit the Equal button, you will then be presented with a new comparison line that will either be equal to or smaller than the last comparison line. Again, you will need to decide: is the comparison line Equal to or Shorter than the standard line? When you hit the Shorter button, this will end the trial and you will need to hit the Next button to start a new trial.

### Practice the two phases of the descending type of trial

Practice until you're comfortable with the buttons and the task (there are about 3 or 4 practice trials):

The second type of trial is very similar to the first type except that the comparison line will appear, at the beginning of the trial, to be either shorter or equal to the standard line. By pressing a sequence of buttons over two phases, you are going to make the comparison line increase in length until it appears longer than the standard line--this is called an ascending type of trial:

### ASCENDING TYPE OF TRIAL

#### Phase one of an ascending type of trial

In the first phase, your task will be to decide if the comparison line is shorter or equal to the standard (see figure immediately below):

If the comparison (bottom) line looks shorter than the standard, hit the Shorter button. If the comparison line looks equal to the standard line, hit the Equal button. If you hit the Shorter button, you will then be presented with a new comparison line that will either be equal to or larger than the last comparison line. Again, you will need to decide: is the comparison line Shorter than or Equal to the standard line? When you hit the Equal button, this will start the second phase of the trial.

#### Phase two of an ascending type of trial

After you press the Equal button in phase one, you will be presented with a new comparison line (see figure below). In this phase, your task will be to decide if the comparison line is equal to or longer than the standard:

If the comparison (bottom) line looks equal to the standard line, hit the Equal button. If the comparison line looks longer than the standard line, hit the Longer button. If you hit the Equal button, you will then be presented with a new comparison line that will either be equal to or larger than the last comparison line. Again, you will need to decide: is the comparison line Equal to or Longer than the standard line? When you hit the Longer button, this will end the trial and you will need to hit the Next button to start a new trial.

### Practice the two phases of the ascending type of trial

Practice until you're comfortable with the buttons and the task (there are about 3 or 4 practice trials):