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Four Choice Reaction Time Task - Keyboard Input
(German instructions)
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 04-11-2017
last updated: 06-15-2023 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 06-15-2023 Millisecond Software
German translations by K. Borchert for Millisecond Software
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BACKGROUND INFO
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This script implements a version of a 4 Choice Reaction Time Task similar to the one described in:
Armstrong et al (2012). Mild Dehydration Affects Mood in Healthy Young Women.
The Journal of Nutrition: Ingestive Behavior and Neurosciences.
Feb;142(2):382-8. doi: 10.3945/jn.111.142000. Epub 2011 Dec 21
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TASK DESCRIPTION
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4 boxes are presented on the screen in a horizontal array. Each box has an assigned response key (by default, the
response keys are matched spatially to the position of their assigned boxes: DFJK).
After a fixed amount of time, one of the boxes turns red and participants are asked to press the
corresponding response key as fast as possible.
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DURATION
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the default set-up of the script takes appr. 2.5 minutes to complete
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DATA OUTPUT DICTIONARY
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The fields in the data files are:
(1) Raw data file: 'fourchoicereactiontimetask_raw*.iqdat' (a separate file for each participant)*
build: The specific Inquisit version used (the 'build') that was run
computer.platform: the platform the script was run on (win/mac/ios/android)
date, time: date and time script was run
subject, group: with the current subject/groupnumber
session: with the current session id
blockCode, blockNum: the name and number of the current block (built-in Inquisit variable)
trialCode, trialNum: the name and number of the currently recorded trial (built-in Inquisit variable)
Note: trialNum is a built-in Inquisit variable; it counts all trials run; even those
that do not store data to the data file such as feedback trials. Thus, trialNum
may not reflect the number of main trials run per block.
totalTrialCount: number of test trials run
position: 1, 2, 3, or 4 => screen position of the stim from left to right
response: the participant's response (scancode of response button)
32 = D (left middle finger)
33 = F (left index finger)
36 = J (right index finger)
37 = K (right middle finger)
selectedPosition: the selected position based on keyboard press
latency: the response latency (in ms) measured from start of trial (onset of the 4 gray boxes)
rt: stores the latency measured from onset of red box (Note: negative latencies => response was made before ONSET of red box)
prematureError: 1 = premature error was made
(premature error: rt < parameters.prematureErrorWindow)
0 = otherwise;
timeoutError: 1 = a timeout error was made;
(timeout error: rt > parameters.timeoutErrorWindow)
0 = otherwise;
incorrectChoice: 1 = a valid (neither premature nor timeout response) but incorrect response was made;
0 = otherwise
acc: the correctness of the response
1 => valid (no premature response nor late response) AND correct choice of response button
0 => otherwise
countPrematureErrors: counts incorrect premature responses
(responses made BEFORE appearance of red box and those made AFTER within the prematureErrorWindow)
countTimeoutErrors: responses made after parameters.timeoutErrorWindow
countIncorrectChoices: counts the number of valid responses (neither premature nor late) that are incorrect response choices
(2) Summary data file: 'fourchoicereactiontimetask_summary*.iqdat' (a separate file for each participant)*
inquisit.version: Inquisit version run
computer.platform: the platform the script was run on (win/mac/ios/android)
startDate: date script was run
startTime: time script was started
subjectId: assigned subject id number
groupId: assigned group id number
sessionId: assigned session id number
elapsedTime: time it took to run script (in ms); measured from onset to offset of script
completed: 0 = script was not completed (prematurely aborted);
1 = script was completed (all conditions run)
totalTrialCount: number of test trials run
propCorrect: proportion correct responses (correct in terms of response button and timing of response)
meanRT: the average reaction time (in ms) of correct responses
std: the standard deviation (in ms) of correct response reaction times
propPrematureErrors: proportion of Premature Errors relative of total number of trials
propTimeoutErrors: proportion of Timeout Errors relative of total number of trials
propIncorrectChoices: proportion of IncorrectChoices (otherwise valid) relative of total number of trials
* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions
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EXPERIMENTAL SET-UP
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1. Practice Block: 10 practice trials with feedback
by default, the positions of the red box is randomly determined with replacement (see section Editable Lists)
error feedback provided
2. Testblock: 100 trials (default; can be adjusted under section Editable Parameters)
by default, the positions of the red box is randomly determined with replacement (see section Editable Lists)
Trial Sequence:
4 gray boxes (default: 500ms; parameters.soa; fixed)-> onset of red box -> waits for response to continue
Two latencies recorded:
1) 'latency' measured from onset of trial (with onset of the 4 gray boxes)
2) values.rt measured from onset of red box
Error Categories:
premature Errors: all responses with values.rt < parameters.prematureErrorWindow (measured from onset of red box)
If participant responds BEFORE red box appears, values.rt will be negative and automatically scored as a prematureError.
timeoutErrors: all responses with values.rt > parameters.timeoutErrorWindow (measured from onset of red box)
incorrectChoiceErrors: all responses that are valid (aka: no premature Error nor a timeoutError) BUT
the incorrect response button was pressed
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INSTRUCTIONS
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provided by Millisecond Software - can be edited under section EDITABLE INSTRUCTIONS
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EDITABLE CODE
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check below for (relatively) easily editable parameters, stimuli, instructions etc.
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code
to further customize your experiment.
The parameters you can change are:
interface:
/pos1X: the first horizonal box position from the left in canvas width percentages (0% at the far left of canvas - 100% far right of canvas)
/pos2X: the second horizonal box position from the left in canvas width percentages
/pos3X: the third horizonal box position from the left in canvas width percentages
/pos4X: the fourth horizonal box position from the left in canvas width percentages
/stimHeight: height of the boxes in canvas height percentages (default: 5%)
Response Keys (from left to right):
/responseKey1: the first response button ("D"); furthest left
/responseKey2: the second response button ("F")
/responseKey3: the third response button ("J")
/responseKey4: the fourth response button ("K"); furthest right
Duration Parameters (in ms):
/soa: Response Stimulus Interval in ms (interval between onset of gray boxes and onset of red box)(default: 500ms)
/prematureErrorWindow: responses made before the end of this window (measured in ms fro m onset of red box)are scored as premature errors (default: 100)
(Note: ALL responses BEFORE appearance of red box are automatically considered premature)
/timeoutErrorWindow: responses made after this response window (measured from onset of red box in ms) are considered 'timeOut Errors' (default: 1000ms)
Example: if a response is made 1000ms AFTER onset of red box, the response is scored as a timeout error.
/readyDuration: duration (in ms) of getting ready trial (default: 5000ms)
/feedbackDuration: duration (in ms) of feedback during the practice trials (default: 1000ms)
Trial Numbers:
/maxTrials: number of trials to run (default: 100)
