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						Four Choice Reaction Time Task - Keyboard Input
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 04-11-2017
last updated: 04-13-2017 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Script Copyright © 04-13-2017 Millisecond Software


BACKGROUND INFO 

											*Purpose*
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


											  *Task*
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.


DATA FILE INFORMATION: 
The default data stored in the data files are:

(1) Raw data file: 'fourchoicereactiontimetask_raw*.iqdat' (a separate file for each participant)*

build:							Inquisit build
computer.platform:				the platform the script was run on
date, time, subject, group:		date and time script was run with the current subject/groupnumber 
blockcode, blocknum:			the name and number of the current block
trialcode, trialnum: 			the name and number of the currently recorded trial
									(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block) 
/totalTrialcount:					number of test trials run
response:						the participant's response (scancode of response button)
/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: values.rt < parameters.prematureErrorWindow)
								0 = otherwise;
/timeoutError:					1 = a timeout error was made; 
								(timeout error: values.rt > parameters.timeoutErrorWindow)
								0 = otherwise;
/incorrectChoice:				1 = a valid (neither premature nor timeout response) but incorrect response was made; 
								0 = otherwise

/correct:						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)*

script.startdate:				date script was run
script.starttime:				time script was started
script.subjectid:				subject id number
script.groupid:					group id number
script.elapsedtime:				time it took to run script (in ms)
computer.platform:				the platform the script was run on
/completed:						0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)
/totalTrialcount:				number of test trials run
/propCorrect:					proportion of correct responses
									Notes: all trials with values.prematureError = 1 OR values.timeoutError = 1 are automatically scored as 0 (incorrect)
									regardless of response key hit
/meanRT:						mean correct response latency (in ms; measured from onset of red box)
/SD:							standard deviations of correct latencies

/propPrematureError:			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


EXPERIMENTAL SET-UP

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


INSTRUCTIONS
provided by Millisecond Software - can be edited under section EDITABLE INSTRUCTIONS

EDITABLE CODE:
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:

The parameters you can change are:
																
Interface:
/pos1_x:						the first horizonal box position from the left in canvas width percentages (0% at the far left of canvas - 100% far right of canvas)
/pos2_x:						the second horizonal box position from the left in canvas width percentages
/pos3_x:						the third horizonal box position from the left in canvas width percentages
/pos4_x:						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:					scancode of the first response button (see Tool -> Keyboard Scancode)
/responsekey1_label:			label of the scancode of the first response button 
/responsekey2:					scancode of the second response button 
/responsekey2_label:			label of the scancode of the second response button
/responsekey3:					scancode of the third response button 
/responsekey3_label:			label of the scancode of the third response button
/responsekey4:					scancode of the fourth response button 
/responsekey4_label:			label of the scancode of the fourth response button

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 from 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)

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