V. Stop Task

A) General Notes

  • Within a session, participants will run through the Stop Task twice, once with incentive and once with no incentive.
  • Each incentive condition includes 1 “GO” practice with 32 trials, 1 “GO with STOP” practice with 32 trials, and 3 real blocks each with 64 trials.
  • The mean “GO” reaction time will be determined based on the mean “GO” RT during the “GO” practice. Participants’ reaction times must be less than their mean in order to receive the full 5 points for fast and accurate “GO” trials and correct “STOP” trials during the incentive block.

B) Program Set-Up: Click on the E-run icon on the desktop, go to the “file” menu and select the “open” option, then navigate to folder containing the “stoptask” file.

[NOTE: DO NOT open the experiment using recently used files at the bottom of the file menu. The full path names are not shown for these experiments and so you can’t be sure that you are running the correct experiment.] Once you have opened the task, then press the [F7] key to start the task. Enter appropriate ID # and one for the session.

1). Instructions for Stop Task

2). Place the response box in the child’s lap.

3). Read the following instructions to the participant.

Once the program is open, press spacebar to get to 2nd screen (corresponds to paragraph below)

“Welcome to “STOP and GO!” During this game we want to see how quickly you can “GO” and how quickly you can “STOP” when you hear a stop beep. This beep will only occur sometimes.

During one part of the game, the computer will tell you how you’re doing and you will earn points depending on how well you’re doing. During the other part of the game you will NOT be told if your answers are correct or wrong, and you will NOT earn points.

We will be playing “Stop and Go” without points first.

So, during this first part of “Stop and Go” the computer will NOT tell you whether each of your answers is correct and you will not earn points.

First I am going to tell you about the “GO” part. You are going to push buttons on this box (point to response box) as quickly as you can when you see an arrow flash up on the screen.

(Press spacebar to advance screen).

When you see an arrow pointing left like this one (point to left arrow on screen),you will use your left pointer finger to push the left button of this box(demonstrate using left pointer finger on leftmost button of response box).You want to press the button as quickly as you can while still pressing the correct button. Try pressing the left button on the box”(Make sure the child is pressing the correct button on the box).

(Push spacebar to demonstrate right arrow and point to right arrow on screen,)

When you see an arrow pointing to the right like this one (point to right arrow on screen)you will use your right pointer finger to push the right button on the box (demonstrate using right point finger on rightmost button of response box.)Again, you want to press the button as quickly as you can while still pressing the correct button. Try pressing the right button on the box” (Make sure the child is pressing the correct button on the box).

“Since it is important to push the buttons as quickly as you can, you’ll want to keep your fingers right on the buttons. Try pushing the buttons a couple of times…You can hold the box in your lap if you would like.” (Have child practice pushing the buttons. Let them hold the box in their lap if it is more comfortable.)

“Remember to go as fast as you can while still pressing the correct button. After you respond you will see a box with an asterisk. You can ignore this box for now. Let’s practice. Get ready…”

When child has their fingers poised and is facing the screen, click the space barto begin practice.

C) Begin “GO” practice.

1) Monitor participants during practice.

2) Provide feedback only if it is clear that the child does not understand the task. Look at the statistics at the bottom of the screen, and if accuracy is below 80% (A < .80); reiterate the instructions about the direction of arrow and response buttons. If the child is not keeping left and right index finders touching the buttons, then remind them to do so. Please make note in the interviewer notes if any of the values are out of the desirable range.

D) End of “GO” practice

(Screen will correspond to Stop Instructions below)

“Great! You know how to do the “GO” part of the game. Now, I am now going to tell you about the “STOP” part.”

“Sometimes you will hear a “beep.” This beep means “STOP” and you should try to stop yourself from pressing the button for the arrow. It is okay if you are not able to stop every time. The beep will only occur sometimes, so you should not wait for the beep. You want to keep pressing the buttons as fast as you can while still pressing the correct button when the arrows appear. We will practice this in a minute.

Can you tell me what you think is going to happen?”

(Provide corrective feedback if child is unable to describe the task.)

“We will now do a practice. Remember to go as fast as you can while pressing the correct button; try and stop when you hear the beep.”(Press the space bar to begin practice.)

E) Begin “STOP and GO” practice.

  • Monitor participant during practice.
  • Provide feedback only if it is clear child does not understand task. Statistics on the bottom of the screen can be helpful indicators of lack of understanding. Indications that the child does not understand the task include accuracy is less than 80% (A < .80), child is not keeping left and right index fingers touching the buttons, child rarely inhibits (I < .20), or child inhibits too much (I >.80). If accuracy is too low, reiterate the instructions regarding the direction of the arrow and the key press. If the child rarely inhibits, remind them that the beep means that they should stop and not respond. If the child is inhibiting too much, then encourage them to work faster. Please make note in the interviewer notes if any of the values are out of the desirable range.

F) End of practice

“Okay, now we are ready to begin the real game. First, you will do “STOP and GO” three times without points. You will not receive any feedback if your answer was right or wrong. You will only see a box in between your responses, which has an asterisk/star in it. Do you have any questions?

Remember: “Go” as fast as you can while still getting the correct answer. “Stop” whenever you hear the stop beep.”(Press the space bar to begin block 1)

G) Begin Block 1 by pressing the space bar.

  • Monitor participant during experiment
  • At the end of each block DO NOT press the space bar unless child is ready to begin next block. Pressing the space bar will immediately begin the next block.
  • At the end of EACH block, provide feedback and record in interviewer notes if the statistics on the bottom of screen if accuracy is less than 80% (A < .80), child rarely inhibits (I < .20), or child inhibits too much (I >.80).
  • Begin Block 2, 3. Before each block is started say,

“Okay are you ready for your next part? Remember: “Go” as fast as you can while still getting the correct answer. “Stop” whenever you hear the stop beep.”

(Press the space bar to begin next blocks.)

H) End of Block 3

(Screen will say ‘Time for a Break’)

“Okay, you are all done with the first three parts of “stop and go” game.

If you would like, you will now have a short break before you continue the “stop and go” game. In the next part of the game you will be able to earn points. Do you need to go to the bathroom or get a drink of water? (If they say no, say,) Would you like to get up and stretch?”(ifno, then just continue.)

I) Instructions for Incentive Condition

(Press spacebar to advance to Instruction screens)

“Okay, we are now going to begin the next part of “Stop and Go”, which will last for about 15 more minutes. This part is like what you just did, except this time the computer will tell you whether each of your answers is correct. You WILL earn points when you are correct. Remember that you are trying to earn as many points as possible so that you can pick a prize. So try as hard as you can to earn a lot of points.

Here is how the points work. During practice you will earn 1 point for every correct button you push.(push spacebar) So, if the arrow that flashes on the screen is pointing left, and you push the left buttonyou will earn 1 point, and if the arrow that flashes on the screen is pointing right, (push spacebar) and you push the right button you will earn 1 point, too. You will not earn any points if you push the incorrect button or if you do not push the button at all, and you will see an empty box with no points in it. The points you earn during practice WILL count toward your total. Remember to go as fast as you can while still pressing the correct button. Let’s practice. Get ready…”

“You will begin practice with just the arrows. There will not be any ‘stop’ beeps in this practice. Remember to go as fast as you can while still pressing the correct button.”(when child has their fingers poised and is facing the screenpress the space bar to begin “GO” practice.)

J) Begin “GO” practice.

  • Monitor participants during practice.
  • Provide feedback only if it is clear that the child does not understand the task (i.e., if accuracy is

below 80%; child is not keeping left and right index finders touching the buttons.) Please make note in the interviewer notes if any of the values are out of the desirable range.

K) End of practice.

(Screen will correspond to instructions below)

“Now we’ll do a practice with the ‘stop’ beeps. Like before, you need to listen for the beep and try to not press the button when you hear it. Remember, sometimes it will be very hard to stop, and you will not be able to stop every time. The ‘stop’ beep will only occur sometimes, so you should not slow down to wait for the beep. You should keep pressing the buttons as fast as you can when the arrows appear.

You will still earn 1 point for pressing the correct button. You will not earn any points for pushing the incorrect button or not pushing the button at all UNLESS you hear a beep.

If you are able to stop yourself from pressing the button when you hear the ‘stop’ beep you will earn 1 point. You will not earn any points if you push the button when you hear the ‘stop’ beep.

Can you tell me what you think is going to happen?”

(Provide corrective feedback if child is unable to describe the task.)

“We will now do a practice. Again, the points you earn during practice WILL count toward your total. Remember to go as fast as you can while pressing the correct button; try and stop when you hear the beep.”(Press the space bar to begin practice.)

L) Begin “STOP and GO” practice.

  • Monitor participant during practice.
  • Provide feedback only if it is clear child does not understand task. Statistics on the bottom of the screen can be helpful indicators of lack of understanding. Indications that the child does not understand the task include accuracy is less than 80% (A < .80), child is not keeping left and right index fingers touching the buttons, child rarely inhibits (I < .20), or child inhibits too much (I >.80). If accuracy is too low, reiterate the instructions regarding the direction of the arrow and the key press. If the child rarely inhibits, remind them that the beep means that they should stop and not respond. If the child is inhibiting too much, then encourage them to work faster.Please make note in the interviewer notes if any of the values are out of the desirable range.

M) End of practice.

“Good job! So far you have__ points! Okay, now that you have some practice, you are ready for the real game.

Now, this time you will earn 5 points for pushing the correct button BUT only if you are going pretty fast. You will earn 2 points if you push the correct button but you are slow. You will not get any points if you push the incorrect button or if you do not push a button at all.

If you are able to stop yourself from pressing the button when you hear the ‘stop’ beep you will earn either 5 points if you have been going fast or 2 points if you have been going slowly. You will earn more points for ‘STOP-ing’ if you ‘GO’ as fast as you can. You will not earn any points if you push the button when you hear the ‘stop’ beep.

So, tell me what you think is going to happen.”

(Provide corrective feedback if the child is unable to describe the task and points)

“You will do “Stop and Go” for points three times so that you can boost your point total. You will be given your point total at the end of each time. Do you have any questions?”

N) Begin Block 1 by pressing the space bar.

  • Monitor participant during experiment
  • At the end of each block DO NOT press the space bar unless child is ready to begin next block. Pressing the space bar will immediately begin the next block.
  • At the end of EACH block, provide feedback and record in interviewer notes if the statistics on the bottom of screen if accuracy is less than 80% (A < .80), child rarely inhibits (I < .20), or child inhibits too much (I >.80).

O) Begin Block 2, 3. Before each block is started say,

“Okay are you ready to play again? Remember: “Go” as fast as you can while still getting the correct answer. “Stop” whenever you hear the stop beep.”(Press the space bar to begin blocks.)

P) End of Stop Task:

“You have completed the “Stop and GO” game. You did a great job. You earned X number of points!”

Record points on interviewer notes form.