Here are some perhaps overly redundant instructions for the current psychophysics experiments.

script is ~/git/psychophys/Crowding/RunOvals.m

Run practice. The first screen will have the fixation cross with the stimulus and 4 flankers at near eccentricity. Use the text in italics as a guideline for instruction, but there is not a verbatim correct way to provide instruction.

During this task, you’ll want to keep your eyes centered on the crosshair there in the center of the screen. The one here that has the gap in it is going to be your target stimulus. The four around it are just distractors. If it is open at the top like it is now, push the joystick forward or up. If it is open on the bottom, pull the joystick backwards towards you or down. The target stimulus will appear randomly to the left or right of the center but at the same distance it is now. You’ll want to make sure your eyes are centered so you don't miss what comes next. We are going to do some practice first.

(Practice is 4 different parts. First: Practice at lower eccentricity)

Now you’re going to respond to just that target without the distractors.

(Run just the target without the distractors at low eccentricity)

Now you’re the target is going to be further from the fixation cross with the distractors again.

(Run practice at high eccentricity)

Now you’re going to respond to just the target without the distractors at that same distance.

(Run just the target without the distractors at high eccentricty)

Do you feel like you understand the task?

(If no, run practice again)

Now we’re going to continue to the main task. During each block, the target will be one of those two fixed distances from the fixation cross, but will appear on either the left or right, just like in practice. You're going to do two blocks with the target closer to the center, and 2 blocks with it further away. What's going to vary is how close the distractors are to the target. Try to see how well you can respond when the distractors get very close to the target. Sometimes it can get hard, but just do your best.

script is ~/git/psychophys/Crowding/RunText.m

Run practice. This will put a crosshair in the center with 3 letters at near eccentricity on the left side.

This task is similar to the task you did earlier with the circles. This is what the stimulus will look like. You'll notice the same fixation cross there in the center. On the left or right side, you're going to see three letters appear. Your task is to identify the letter that appears in the center. The center letter will either appear at this distance (point to screen) or if you can click (wait for click; screen now shows stimulus at high eccentricity on right) at this distance from the center. So this stimulus is just going to flash on the screen–and if you can click on more time (wait)–will be followed by this EXACT screen. These are the only seven letters that will appear at the target stimuli. You will use the mouse to select the letter that you just saw. Importantly, the game will record your selection when you RELEASE the mouse click, so if you decide to change your answer you can drag to a different answer, but if you're going to quickly you might move away from the letter you meant to select before you release, so be careful. Do you have any questions? Okay, go ahead and click one more time (wait) and now you're going to do a fairly extensive practice. The stimuli are going to appear at both of those distances from the center, and there will also be some trials where you just have the target letter presented by itself without distractors.

Practice takes around 2 minutes. Many people will remark at how fast it's going, and how they don't feel they can see it at all. However, almost everyone does perform at above chance. The practice is long enough that it's unlikely anyone would need/want to do it again. After it's done;

Okay, so now we're going to continue onto the main task. We're going to do 4 blocks of this. Within each block, the distance between the center and the target stimulus will be the same, but the distance between the target letter and the distractors will vary. There will be a few trials where the target letter is presented by itself. Any questions?