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										*SERIAL SUBTRACTION TASK*
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 06-20-2016
last updated:  03-11-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-11-2020 Millisecond Software

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BACKGROUND INFO 	
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This script implements a Serial Subtraction Task akin to the Serial7/Serial3 task.
The Serial Subtraction Task is a working memory performance task of the 'updating' category.

The implemented procedure is based on:

Kennedy, D.O. & · Andrew B. Scholey, A.B. (2000). Glucose administration, heart rate and cognitive performance:
effects of increasing mental effort. Psychopharmacology (2000) 149:63–71.

Note: in this script, the Serial Subtraction task uses written input instead of oral input

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TASK DESCRIPTION
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Participants are given a randomly generated 3 digit number between 900-999 and are asked to subtract 7 (default)
as often as they can within a 2 minute time frame (adjustable).	
Participants enter their solution by selecting digit buttons 0-9 with the mouse.
Responses can be corrected before submit.	
Correct solutions are based on the last entered number (whether or not that response was correct).								  

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DURATION 
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the default set-up of the script takes appr. 2 minutes to complete
(duration can be edited under section Editable Parameters)

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

(1) Raw data file: 'serialsubtractiontask_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
script.sessionid:					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. 
									
values.currentNumber:				contains the current start Number to be presented 
parameters.targetDiff:				contains the target difference between numbers (here: 3)
values.correctSolution:				stores the current correct solution
										Note: the current correct solution number is generated based on the last proposed solution.
										Thus if the last proposed solution was incorrect, the new correct solution is
										based on the incorrect proposed solution
										
values.proposedSolution:			stores the entered proposed solution for the current subtraction
correct:							the correctness of the response (1 = correct; 0 = incorrect)
latency: 							the response latency (in ms); measured from onset of response dial
values.countResponses:				counts the number of given responses
values.countErrors:					counts the number of errors made


(2) Summary data file: 'serialsubtractiontask_summary*.iqdat' (a separate file for each participant)*

computer.platform:					the platform the script was run on (win/mac/ios/android)
script.startdate:					date script was run
script.starttime:					time script was started
script.subjectid:					assigned subject id number
script.groupid:						assigned group id number
script.sessionid:					assigned session id number
script.elapsedtime:					time it took to run script (in ms); measured from onset to offset of script
script.completed:					0 = script was not completed (prematurely aborted); 
									1 = script was completed (all conditions run)							
									
parameters.targetDiff:				contains the target difference between numbers (here: 7)									
values.RoundCount:					counts the number of rounds run (default: 1 round with difference = 7)
values.countResponses:				counts the number of given responses
values.countErrors:					counts the number of errors made

* 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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This Inquisit script provides a template for a Serial Subtraction Task.
The target Difference can be set under Editable Parameters. By default, participants are asked to perform
a Serial7 task.

Participants are given a target number and are asked to start subtracting 7 from it in their heads. 
They enter their solution to each new subtraction via a response dial.
The response is evaluated in regard to the previously entered solution (whether or not that was a correct
solution).
The task is over after 2 minutes (default)

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STIMULI
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randomly generated 3 digit start numbers (generated without replacement across blocks) between 900-999

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INSTRUCTIONS 
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Instructions are not original to the task. They are provided by Millisecond Software
as htm/html pages and simple page elements and can be edited either by changing
the provided htm/html files or directly under Editable Instructions.
To edit htm/html-files: open the respective documents in simple Text Editors such as TextEdit (Mac)
or Notepad (Windows).

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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:

/TargetDiff:					the target difference btw. numbers (here: 7)
/taskDuration:					task duration in ms (default: 120000ms = 2 min)					
/circleproportion:				proportion of canvas height used for the circle radius of response buttons (default: 0.3)