Return to the Food Go/No Go Task page
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										FOOD GO-NOGO TASK
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 02-21-2017
last updated:  03-09-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-09-2020 Millisecond Software

Millisecond Software thanks Dr. John Gunstad for his help with this script!

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BACKGROUND INFO 	
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Go/Nogo Tasks are used as behavioral measures of inhibition and cognitive control. The Food Go/No Tasks leverages
this paradigm to investigate cognitive control in the context of food.

Teslovich, T. et al (2014). Probing behavioral responses to food: Development of a foodspecific
go/no-go task. Psychiatry Res, 30, 219(1): 166–170.

E-prime script available at: 
http://fablab.yale.edu/page/assays-tools

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TASK DESCRIPTION	
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Go-Nogo task: general task is to press the spacebar whenever an stimuli of the Go category  (e.g. food images) 
is presented and refrain from responding whenever a stimuli of the NoGo category (e.g. toys) is presented.
In this script, participants work through 4 conditions:
(1) high-calorie food “go” with toy “no-go” 
(2) low-calorie food “go” with toy “no-go”
(3) toy “go” with high-calorie food “no-go”
(4) toy “go” with low-calorie food “no-go”
Each condition runs ~75% go trials (35) and ~25% (13) nogo trials. 

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DURATION 
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the default set-up of the script takes appr. 20 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: 'foodgonogo_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.order:						the order in which the four test blocks were run
				
values.calorieType:					"high" vs. "low" vs. "ctrl"
values.goType:						"go" vs. "nogo"
values.ITI:							current intertrial interval in ms
									
values.stim:						stores the currently presented target picture

response:							the participant's response (scancode of response button)
										Spacebar: 57
										no response: 0
										
correct:							the correctness of the response (1 = correct; 0 = otherwise)
latency: 							the response latency (in ms); measured from onset of image until response is registered


(2) Summary data file: 'foodgonogo_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)

values.order:						the order in which the four test blocks were run

expressions.propCorrect:			overall proportion correct across all trials
expressions.meanRT:					mean correct reaction times across all GO trials
expressions.SD:						standard deviation of correct reaction times in GO trials
expressions.maxRT:					reaction time that is 3 standard deviations slower than the overall mean
expressions.minRT:					reaction time that is 3 standard deviations faster than the overall mean


expressions.omissionFOOD:			miss rate in food (across low and high calorie food) GO trials (should have responded to food but did not)

expressions.commissionFOOD:			false alarm rate in food (across low and high calorie food) NOGO trials (should NOT have responded to food but did)
										Note: => the higher the commission rate, the lower cognitive control in the face of food stimuli 
										(aka cannot refrain from responding)
										
expressions.meanRT_FOOD:			mean hit reaction time in food GO trials (outliers removed*)

expressions.omissionHC:				miss rate in high calorie GO trials (should have responded to high calorie food but did not)

expressions.commissionHC:			false alarm rate in high calorie NOGO trials (should NOT have responded to high calorie food but did)
										Note: => the higher the commission rate, the lower cognitive control in the face of high calorie 
										food stimuli (aka cannot refrain from responding)
										
expressions.meanRT_HC:				mean hit reaction time in high calorie GO trials (outliers removed*)

						
expressions.omissionLC:				miss rate in low calorie GO trials (should have responded to low calorie food but did not)

expressions.commissionLC:			false alarm rate in low calorie NOGO trials (should NOT have responded to low calorie food butdid)
										Note: => the higher the commission rate, the lower cognitive control in the face of low calorie 
										food stimuli (aka cannot refrain from responding)
										
expressions.meanRT_LC:				mean hit reaction time in low calorie GO trials (outliers removed*)


expressions.omissionCTRL:			miss rate in CTRL GO trials (should have responded to CTRL stim but did not)
expressions.commissionCTRL:			false alarm rate in CTRL NOGO trials (should NOT have responded to CTRL stim but did)
expressions.meanRT_CTRL:			mean hit reaction time in CTRL GO trials (outliers removed*)

expressions.omissionCTRL_HC:		miss rate in CTRL GO trials (when paired with high calorie nogo foods) (should have responded but did not)
expressions.commissionCTRL_HC:		false alarm rate CTRL NOGO trials (when paired with high calorie  go foods)(should NOT have responded to high calorie CTRL but did)
expressions.meanRT_CTRL_HC:			mean hit reaction time in CTRL GO trials ((when paired with high calorie nogo foods) (outliers removed*)

expressions.omissionCTRL_LC:		miss rate in CTRL GO trials (when paired with low calorie nogo foods) (should have responded but did not)
expressions.commissionCTRL_LC:		false alarm rate CTRL NOGO trials (when paired with low calorie  go foods)(should NOT have responded to low calorie CTRL but did)
expressions.meanRT_CTRL_LC:			mean hit reaction time in CTRL GO trials ((when paired with low calorie nogo foods) (outliers removed*)


* 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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(I) Practice: 
~3min practice session with a) Food (high and low calorie) Go / Toy Nogo and b) Food Nogo / Toys Go
Total practice trials: 22; trial/stimuli order fixed (see http://fablab.yale.edu/page/assays-tools)

(II) Test:
4 conditions tested: 
(1) high-calorie food “go” with toy “no-go” (block.highGO, 48 trials: 35 go trials, 13 nogo trials)
(2) low-calorie food “go” with toy “no-go”, (block.lowGO)
(3) toy “go” with high-calorie food “no-go”, (block.highNOGO)
(4) toy “go” with low-calorie food “no-go”, (block.lowNOGO)

tested within participants in a blocked format. The order of the 4 conditions were counterbalanced
by groupnumbers (4 orders, see section EXPERIMENT).
Each block runs 35 go trials and 13 nogo trials (= 4 x 48 test trials = 192 test trials total)
By default all blocks run trials/stimuli in a fixed order. Orders taken from:
http://fablab.yale.edu/page/assays-tools

To run the trials/stimuli in random order, go to section Editable Lists and follow further instructions.

Default Trial Timings:
Fixation Cross (ITI duration: either fixed or random*) -> Target Image (500ms) -> Fixation Cross until response or up to 2000ms (End of Trial)

* if parameters.runRandomITI is set to false, a fixed ITI is run. Default is: 2500ms (can be set under section Editable Parameters).
Random ITIs are controlled by list.intertrialIntervals under section Editable Lists.
**Each block starts with a trial that presents the fixation cross in red for 500ms 

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STIMULI
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Stimuli used provided by:
http://fablab.yale.edu/page/assays-tools

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INSTRUCTIONS 
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instructions modelled after instructions used by:
http://fablab.yale.edu/page/assays-tools

all instructions 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:

/responseKey:						go-responsekey scancode (default: " " -> spacebar)

/fixationSize:						the size of the fixation cross in proportion to canvas height (default: 8%)
/picSize:							the proportional size of the pictures (default: 60%)

/pictureDuration:					the duration (in ms) that the images are on screen (default: 500ms)
/RW:								the duration (in ms) of the response window; measured from onset of target image (default: 2500ms)
/runRandomITI:						true (1): a random ITI is selected from list.intertrialIntervals
									false (2): a fixed ITI is selected (see parameters.fixedITI)
/fixedITI:							the fixed intertrial interval (in ms) if parameters.runRandomITI = false (default: 2500ms)