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										FOOD GO-NOGO TASK
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 02-21-2017
last updated: 09-20-2017 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Script Copyright © 09-20-2017 Millisecond Software

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


BACKGROUND INFO 

											*Purpose*
This script implements a food go/nogo task based on:

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


											  *Task*
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. 


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

(1) Raw data file: 'foodgonogo_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) 

/order:							the order in which the four test blocks were run
/goType:						"go" vs. "nogo"				
/calorieType:					"high" vs. "low" vs. "ctrl"
/ITI:							current intertrial interval in ms
									
stimulusitem:					the presented stimuli in order of trial presentation
/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 = incorrect)
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)*

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)
/order:							the order in which the four test blocks were run

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

/omission_HC:					miss rate in high calorie GO trials (should have responded but did not)
/commissionHC:					false alarm rate in high calorie NOGO trials (should NOT have responded but did)
/meanRT_HC:						mean hit reaction time in high calorie GO trials (outliers removed*)

/omission_LC:					miss rate in low calorie GO trials
/commissionLC:					false alarm rate in low calorie NOGO trials
/meanRT_LC:						mean hit reaction time in low calorie GO trials (outliers removed*)

/omission_CTRL:					miss rate in control GO trials
/commissionCTRL:				false alarm rate in control NOGO trials
/meanRT_CTRL:					mean hit reaction time in control GO trials (outliers removed*)
=> control data combined across the 2 blocks in which control items were Go items (for omissions and reaction times)
and the 2 blocks in which control items were nogo items (for commission errors) 

*NOTE: outliers in this script are defined as: reaction times that are more than 3 standard deviations faster or slower
than the overall reaction time (expressions.meanRT)


* 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

(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 


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


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

all 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:

/responseKey:						go-responsekey scancode (default: 57 -> spacebar); check out Tools-> Keyboard Scancode for more options
/responseKeyLabel:					the label that corresponds to the selected response scancode (here: 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)

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