Difference between revisions of "CNP SCWT"

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(Created page with 'go back to HTAC === Basic Task Description === The Stroop task is a classic psychological test of inhibitory control. In the task, color words (typically red, green, and …')
 
(Task Procedure)
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=== Task Procedure ===
 
=== Task Procedure ===
This version of the Stroop task was programmed in E-Prime 2.0. Participant responses are made on computer keyboard, using the right and left arrow keys.  At the beginning of the task, instructions are presented on the screen in yellow, size 20 Arial font, with a black screen background. The instructions are as follows:
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This version of the Stroop was programmed in E-Prime 2.0. Participant responses are made on computer keyboard, using the right, down, and left arrow keys.  At the beginning of the task, instructions are presented on the screen in yellow, size 16 Arial font, with a black screen background. The instructions are as follows:
  
<center>"In this task, you will see a word on the screen. Please respond as quickly as possible with the finger that corresponds to the color ink each word is printed in.  Press any key for more instructions.  (Participant hits key)
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Slide 1:
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<center>"In this task, you will see a word on the screen.
  
If the word is in red ink please respond quickly with the left key.  If the word is in green ink, please respond quickly with the middle key.  If the word is in blue ink, please respond quickly with the right key.  The ink colors are above your response keys if you forget (point to the colors above the response keys).  Press any key to practice."</center>
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Please respond as quickly as possible to
 +
the INK COLOR each word is printed in."</center>
  
During the first practice, the participant may ask if they are supposed to respond to the color of the ink or what the word says.  You should tell them to respond to the color of the ink. However, in the first practice, the word and the ink match, so it should not be too confusing at this point.  The procedure is described in more detail after the first practice, at which time you say,
+
Slide 2:
 +
<center>"If the word is in  red ink please respond quickly with the LEFT key.
 +
If the word is in green ink please respond quickly with the MIDDLE key.
 +
If the word is in blue ink please respond quickly with the RIGHT key.
  
<center>"In the previous trial, the words always matched the ink color. In the next trials, sometimes the word and the ink color will not match.  For example, the word blue may be printed in red ink, like this (point to the word blue). When this happens, you should still respond to the color of the ink, NOT what the word says. So for the word above, you would hit the red key (point to the red key). Press any key to continue."</center>
+
The ink colors are above your response keys if you forget.
 +
Please ask the experimenter to start the PRACTICE when you are ready."</center>
  
Remember, respond as quickly as possible to the color of the ink, NOT what the word says.  Press any key to practice."</center>
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Each practice trial begins with a target word presented on a black screen (150 ms), followed by a blank screen for 1850, 1900, or 1950 ms.  A fixation point (white +) is then presented for 250 ms.  The time limit for responding to the target stimulus is 2000 ms (beginning at stimulus onset).  The initial block of 18 practice trials includes congruent words only, in which the word and ink color are the same.
  
Remind the participant which key corresponds with which ink color. 
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Following these initial congruent practice trials, participants are then shown another instruction slide that prepares them for the mixed block of congruent and incongruent practice trials:
  
• After the practice trials the participant is instructed to “Please take a short break”.  
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<center>"In the previous trial, the word always matched the ink color.
• The participant should stand up and get away from the computer for at least a minute.  
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In the next trials, sometimes the word and the ink color will not match.
• After the break, Say,
+
For example, the word blue may be printed in red ink, like this:"
 +
(example given)
  
 +
When this happens, you should still respond to the color of the ink, NOT what the word says. So for the word above, you would hit the (red) key"</center>
  
Experimental block trials (acquisition and reversal conditions) follow general parameters similar to the practice trials, and begin with a box in the center of the screen with the word "Press."  If participants do not press the middle button within 5000 ms, they receive the following feedback in the center of the screen: "Please press the middle key to begin the next trial."  After pressing the middle key, the word "Hold" appears in the center box and remains on the screen for either 1000 ms, 1500 ms, 2000 ms, or 2500 ms.  These 4 durations for the "Hold" cue are randomized across all trials.  If they release the middle key prematurely during this time, they receive the following feedback and the trial restarts: "Oops!  Make sure to wait for the doors. Let's try again."  Following the "Hold" delay, two doors appear on the left and right sides of the screen.  The doors remain on the screen for up to 2000 ms or until the participant presses the left or right key.  While the doors are present, the "Hold" cue is then replaced by "Left or Right?" which prompts the participants to press either the left or right key.  If participants take too long to respond (more than 2000 ms), they receive the following feedback in the center of the screen: "Oops!  Didn't get your response in time. Let's try again."  If participants press the right or left key will still pressing the middle key (i.e., using two different fingers to respond), they receive the following feedback in the center of the screen: "Oops!  Please remember to use only one finger and do not respond before the doors appear.  Let's try again."  Feedback slides are all presented for a total of 2000 ms.
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Another instruction slide then appears:
 +
<center>"Remember: respond as quickly as possible to the color of the ink, NOT what the word says.
  
At the beginning of the acquisition block, the computer randomly selects either the left or right door to be initially associated with reward.  Participants receive $0.50 each time they select the rewarded door. As soon as the participant presses the key corresponding to the side of the rewarded door, then they immediately see two quarters appear in place of the door and hear a rewarding sound (cash register noise).  Rewarded selections also present a running total of earnings on the bottom of the screen. If participants select the door that is not associated with the reward, they immediate see an empty white box in place of the door and hear a negative sound (buzzing noise). The timing of the reversal is based on a performance criterion. Of note, this criterion has been revised since the task was initially employed (the initial version of this task (DRLT) used a performance criterion of 9 out of 12 correctly-completed trials, computed as a moving window)The current version of the task (DRLT_v2) uses a performance criterion of 5 consecutive correctly-completed trials.
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If the word is in  red ink please respond quickly with the LEFT key.
 +
If the word is in green ink please respond quickly with the MIDDLE key.
 +
If the word is in blue ink please respond quickly with the RIGHT key.
 +
 
 +
Please ask the experimenter to start the PRACTICE when you are ready."</center>
 +
 
 +
A second block of practice trials are administered in which there is a mix of congruent (75%) and incongruent (25%) trialsA total of 24 mixed practice trials are presented.
 +
 
 +
Another instruction slide then appears:
 +
<center>"We will now start the final task.  Do the same as you did
 +
previously: Respond as quickly as possible to the color
 +
of the ink, NOT what the word says.
 +
 
 +
If the word is in  red ink please respond quickly with the LEFT key.
 +
If the word is in green ink please respond quickly with the MIDDLE key.
 +
If the word is in blue ink please respond quickly with the RIGHT key.
 +
 
 +
Please ask the experimenter to start the TEST when you are ready."</center>
 +
 
 +
Experimental trials follow the same general parameters as the practice trialsA total of 152 experimental trials are administered.  Each of the 12 combinations of congruency, arrow direction, and spatial placement occur 12 different times.
  
 
=== Task Structure Detail ===
 
=== Task Structure Detail ===

Revision as of 02:43, 25 June 2011

go back to HTAC


Basic Task Description

The Stroop task is a classic psychological test of inhibitory control. In the task, color words (typically red, green, and blue) are printed in an ink color that does not match what the words say (e.g., the word green is printed in red ink). Because the reading response is an automatic and habitual tendency in literate individuals, the participant must inhibit this reading response in order to identify the color of ink the word is printed in. In most Stroop task paradigms, there are at least two conditions—congruent and incongruent. In the congruent condition, the color words are printed in an ink color that matches the word. In the incongruent condition, the color word and the ink color do not match. Then, depending on the particular Stroop method, the time with which an individual can identify the ink color in the congruent and incongruent conditions is compared to give an index of inhibitory control. The current Stroop task uses a computer paradigm, in which the colors are represented with three response keys. Throughout this task, it is the goal of the participant to hit the key that corresponds with the ink color, not what the words say. There are also practice trials that help acclimate the participant to the task.

Task Procedure

This version of the Stroop was programmed in E-Prime 2.0. Participant responses are made on computer keyboard, using the right, down, and left arrow keys. At the beginning of the task, instructions are presented on the screen in yellow, size 16 Arial font, with a black screen background. The instructions are as follows:

Slide 1:

"In this task, you will see a word on the screen.

Please respond as quickly as possible to

the INK COLOR each word is printed in."

Slide 2:

"If the word is in red ink please respond quickly with the LEFT key.

If the word is in green ink please respond quickly with the MIDDLE key. If the word is in blue ink please respond quickly with the RIGHT key.

The ink colors are above your response keys if you forget.

Please ask the experimenter to start the PRACTICE when you are ready."

Each practice trial begins with a target word presented on a black screen (150 ms), followed by a blank screen for 1850, 1900, or 1950 ms. A fixation point (white +) is then presented for 250 ms. The time limit for responding to the target stimulus is 2000 ms (beginning at stimulus onset). The initial block of 18 practice trials includes congruent words only, in which the word and ink color are the same.

Following these initial congruent practice trials, participants are then shown another instruction slide that prepares them for the mixed block of congruent and incongruent practice trials:

"In the previous trial, the word always matched the ink color.

In the next trials, sometimes the word and the ink color will not match. For example, the word blue may be printed in red ink, like this:" (example given)

When this happens, you should still respond to the color of the ink, NOT what the word says. So for the word above, you would hit the (red) key"

Another instruction slide then appears:

"Remember: respond as quickly as possible to the color of the ink, NOT what the word says.

If the word is in red ink please respond quickly with the LEFT key. If the word is in green ink please respond quickly with the MIDDLE key. If the word is in blue ink please respond quickly with the RIGHT key.

Please ask the experimenter to start the PRACTICE when you are ready."

A second block of practice trials are administered in which there is a mix of congruent (75%) and incongruent (25%) trials. A total of 24 mixed practice trials are presented.

Another instruction slide then appears:

"We will now start the final task. Do the same as you did

previously: Respond as quickly as possible to the color of the ink, NOT what the word says.

If the word is in red ink please respond quickly with the LEFT key. If the word is in green ink please respond quickly with the MIDDLE key. If the word is in blue ink please respond quickly with the RIGHT key.

Please ask the experimenter to start the TEST when you are ready."

Experimental trials follow the same general parameters as the practice trials. A total of 152 experimental trials are administered. Each of the 12 combinations of congruency, arrow direction, and spatial placement occur 12 different times.

Task Structure Detail

This is what we had worked on before, but could use updating. We'd like to capture a schema that can handle each of the tasks in the CNP, so please think general when editing -fws

  • Task Structure (please given an overview of the task procedures here [i.e., overall design, block, trial, and within-trial event structure and timing])
    • The DRLT has two instructional screens at the outset, followed by practice trials and the experimental session comprised of pre-reversal and post-reversal blocks of trials.
      • Two instructional screens. Screens are advanced with a left mouse click from the examiner.
        • 1. Basic task description.
        • 2. Introduction to the practice trials.
      • Practice trials (repeated until 3 consecutive trials with responses < 2000 ms).
        • Press Cue Slide (infinite until middle key is pressed).
        • Hold Cue Slide (randomized duration of 2000 ms or 2500 ms).
          • Early Response Feedback (3000 ms) presented if participants release the middle key prematurely.
        • Door Slide (4000 ms).
          • No/Slow Response Feedback (2000 ms) presented if participants do not respond to doors within 2000 ms.
      • Instruction screen reminds participants of the rules and introduces the experimental trials.
      • Experimental trials (up to 60 trials).
        • Press Cue Slide (5000 ms or until middle key is pressed).
          • No Response Feedback (2000 ms) presented if participants do not press the middle key within 5000 ms.
        • Hold Cue Slide (randomized duration of 1000, 1500, 2000, or 2500 ms).
          • Early Response Feedback (3000 ms) presented if participants release the middle key prematurely.
        • Door Slide (2000 ms).
          • No/Slow Response Feedback (2000 ms) presented if participants do not respond to doors within 2000 ms.
          • One Finger Feedback (2000 ms) presented if participants respond to doors while still pressing the middle key.
      • End. Thank you screen presented. Grand Total Earnings also displayed.
    • Timing
      • Instruction screens are static until advanced by examiner with a left mouse click.
      • Press Cue Slides (5000 ms until until middle key is pressed).
      • Hold Cue Slides (1000, 1500, 2000, or 2500 ms).
      • Door Slides (2000 ms or until left or right key is pressed).
      • Feedback Slides (2000 ms).
      • The ending thank you screen is static until advanced by the examiner with left mouse click.
  • Stimulus Characteristics
    • sensory modality: Visual. Doors are gray and appear slightly opened against a black opening. Feedback during the task is black text in size 24 Arial font.
    • functional modality: visuoperceptual and linguistic (understanding of text).
    • presentation modality: computer display, audio, directions are assisted by examiner.
  • Response Characteristics
    • responses required: middle key for beginning each trial, left or right key press for selecting door.
      • effector modality: Manual button press.
      • functional modality: Manual button press.
    • response options (e.g., yes/no, go/no-go, forced choice, multiple choice [specify n of options], free response): press, hold, left or right door.
    • response collection (e.g., examiner notes, keyboard, keypad, mouse, voice key, button press): Button press and recording of responses in Eprime 2.0.

Task Schematic

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File:Xx.JPG

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Task Parameters Table

File:.png

Stimuli

Stimuli consisted of two doors simultaneously presented in the left and right sides of a gray screen. Visual reward feedback was an image of two quarters, which appeared in place of the correct door. Visual non-reward feedback was an empty white square, which appeared in place of the incorrect door.

Auditory reward feedback was a cash register sound that lasted approximately 500 ms. Auditory non-reward feedback was a buzzer sound that lasted approximately 500 ms.

A fixation stimulus was a small white square that appeared in the middle of the screen and prompted participants to either "Press" the middle key to begin each trial, "Hold" the middle key to wait for the doors, or select "Left or Right?" once the doors appeared.

Dependent Variables

The primary dependent variables associated with this task have been the total number of trials to criterion during acquisition and reversal conditions (Laughlin et al., 2011). Other dependent variables that may be of interest include the number of reversal errors, mean RT on reversal error trials, and overall change in RT across the final 5 consecutive correct trials in acquisition and reversal conditions.

DRLT Variable Table.JPG

Cleaning Rules

If any of the derived variables listed above are missing, participants should be flagged for exclusion. Additionally, participants who are outliers in the number of trials administered for acquisition or reversal conditions should be flagged for follow up.

Code/Algorithms


History of Checking Scoring:

  • David Kaufman independently checked Stone's results in September 2010 and May 2011 and found his results to be accurate.

Data Distributions

References

Laughlin RE, Grant TL, Williams RW, Jentsch JD. (2011). Genetic dissection of behavioral flexibility: reversal learning in mice. Biol Psychiatry, 69: 1109-16.

Robbins TW. (2000). Chemical neuromodulation of frontal-executive functions in humans and other animals. Exp Brain Res, 133:130-138.