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										Visual Simon Task
SCRIPT INFO

last updated: 01-26-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC
Copyright © 01-26-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
	This script implements a simple visual Simon Task along the lines of experiment 1 described in:

	Bialystok, E., Craik, F. I. M., Klein, R., & Viswanathan, M. (2004). Bilingualism, Aging, 
	and Cognitive Control: Evidence From the Simon Task. Psychology and Aging, 19(2), 290-303.

											  *Task*
	Brief overview taken from Bialystok et al., 2004, p. 292 (slightly adapted):

	Each trial begins with a fixation cross in the center of the screen, that remains visible for 800 ms
	and is followed by a 250-ms blank interval. At the end of this interval, a red or blue square appears 
	on either the left or the right side of the screen and remains on the screen for 1,000 ms if there is 
	no response. Participants are instructed to press the left shift key when they see a blue square 
	and the right shift key when they see a red square. Response timing begins with the onset of the 
	stimulus, and the response terminates the stimulus. There is a 500-ms blank interval before the onset 
	of the next trial.


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

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

build:							Inquisit build
computer.platform:				the platform the script was run on
date, time, subject:			date and time script was run with the current subjectnumber 
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
/congruence:					congruent vs. incongruent
/ stimtype:						Blue Square vs. Red Square
/ stimhpos:						left vs. right
response:						the participant's response (scancode of response)
correct:						the correctness of the response (1 = correct; 0 = incorrect)
latency: 						the response latency in ms

(2) Summary data file: 'VisualSimonTask_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)
/propcorrect:					proportion correct across all test trials
/meanRT:						mean latency of correct test trials in ms
/propcorrect_congruent:			proportion correct of congruent test trials
/meanRT_congruent:				mean latency of correct congruent test trials in ms
/propcorrect_incongruent:		proportion correct of incongruent test trials
/meanRT_incongruent:			mean latency of correct incongruent test trials in ms


EXPERIMENTAL SET-UP
	The experiment begins with eight practice trials, and participants must complete all eight trials success-
	fully to proceed to the experimental trials. If a mistake is made, participants are given additional prac-
	tice trials until all eight trials are completed without error.
	
	The following 28 experimental trials, half of which present the square on the same side as the associ-
	ated response key (congruent trials) and half of which present the square on the opposite side 
	(incongruent trials), are presented in a randomized order.	


STIMULI
red and blue square - size can be controlled via parameters.squaresize under section Editable Parameters

INSTRUCTIONS
Instructions 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:

/responsekeyblue:				the scancode of the left response button for a blue square (default: 42)
/responsekeyblue_label:			the label of the scancode of the left response button for a blue square (default: left Shift)
/responsekeyred:				the scancode of the right response button for a red square (default: 54)
/responsekeyred_right:			the label of the scancode of the right response button for a red square (default: right Shift)

/fixationcross_duration:		the duration of the fixation cross in ms (default: 800)
/ISI:							the interstimulus interval between fixation cross and square in ms (default: 250)
/responsewindow:				the responsewindow/duration of square in ms (default: 1000)
/ITI:							the intertrial interval in ms (default: 500)

/left_x:						the left square coordinate in % of screen canvas (default: 15%)
/right_x:						the left square coordinate in % of screen canvas (default: 85%)
/squaresize:					the square size in % of canvas height (default: 25%) 

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