Return to the Food Stroop (Keyboard) page
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							*Food Stroop Task -- Blocked Version*
							(with keyboard input)
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last updated:  03-12-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 03-12-2020 Millisecond Software

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BACKGROUND INFO 	
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This script implements a blocked Food Stroop by Millisecond Software.
The classic Stroop paradigm demonstrates the interference of word meaning on naming the color in which the words 
are written as measured by reaction time/accuracy differences to color-meaning congruent and color-meaning 
incongruent combinations.  The Food Stroop takes advantage of this basic Stroop interference effect 
by comparing responses to food related words to color and neutral animal words.
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TASK DESCRIPTION	
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Participants get words of 6 different conditions (e.g. unhealthy and healthy foods, animal names, and color words)
in 4 different colors and are asked to press one of 4 keyboard keys as fast as possible.
											  
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DURATION 
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the default set-up of the script takes appr. 5 minutes to complete
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DATA FILE INFORMATION 
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The default data stored in the data files are:

(1) Raw data file: 'foodstroop_keyboardinput_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.stimword:					contains the current stim word
values.stimworditemnumber: 			stores the itemnumber of the current stimword

values.stimcolor:					contains a numeric representation of the current word's display color: 
										1=red, 
										2=green, 
										3=blue, 
										4=yellow
										
values.condition: 					contains a numeric representation of the current condition: 
										1=congruent color/word
										2=incongruent color/word
										3=HPF (high calorie food)
										4=NTF (low calorie food)
										5=HPFA (animal comps for the high calorie food category), 
										6=NTFA (animal comps for the low calorie food category)

									
response:							the participant's key response (scancode of response button)
										scancode/label for the red response button (default: 32 -> d)
										scancode/label for the green response button (default: 33 -> f)
										scancode/label for the blue response button (default: 36 -> j)
										scancode/label for the yellow response button (default: 37 -> k)
										
values.responseCategory:			the interpreted key response										
										1=red, 
										2=green, 
										3=blue, 
										4=yellow										
																				
correct:							the correctness of the response (1 = correct; 0 = incorrect)
latency: 							the response latency (in ms); measured from onset of word


(2) Summary data file: 'foodstroop_keyboardinput_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)
									
expressions.propcorrect:			overall proportion correct of test trials
expressions.meanRT:					overall mean correct latencies of test trials (in ms)
+ separate measures for each of the 6 experimental conditions

CC=congruent color/word
IC=incongruent color/word
HPF (high calorie food)
NTF (low calorie food)
HPFA (animal comps for the high calorie food category), 
NTFA (animal comps for the low calorie food category)
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EXPERIMENTAL SET-UP 
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1 Practice Block: 4 trials with "GREEN", "RED", "CAT", "BANANA"

6 Test Blocks: 6 x 12 trials tested in blocked* design by default
1) Congruent Color Words: presents 12 color words (red, blue, green, yellow) in the congruent color (3 repetitions of each color word with constraint that the same color cannot presented consecutively)
2) Incongruent Color Words: presents 12 color words (red, blue, green, yellow) in incongruent colors (3 repetitions of each color word; each time it is presented in a different incongruent color with constraint that the same color cannot presented consecutively)
3) unhealthy food choices: presents 12 unhealthy food choices in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively )
4) healthy food choices: presents 12 healthy food choices in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively )
5) animals (control for unhealthy food choices): presents 12 animals in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively)
6) animals (control for healthy food choices): presents 12 animals in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively)
- order of blocks is randomly selected

*blocked: the set-up of this script also allows to run the condition in a mixed design (without the constraint of repeated color selections)

Trial Sequence:
Fixation Cross for 200ms -> Stim word until verbal response (recorded but not evaluated)

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STIMULI
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see section Editable Stimuli

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INSTRUCTIONS 
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see 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:

Responsekeys/Labels:
/keyred:							the red response button (default: 32 -> d)
/keygreen:							the green response button (default: 33 -> f)
/keyblue:							the blue response button (default: 36 -> j)
/keyyellow:							the yellow response button (default: 37 -> k)

/getReadyDuration:					the duration (in ms) of the get-ready-trial (default: 5000ms)