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										Alcohol Go/Nogo Task
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 12-21-2017
last updated:  03-06-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-06-2020 Millisecond Software

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BACKGROUND INFO 	
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Go/Nogo Tasks are used as behavioral measures of inhibition and cognitive control. The Alcohol Go/No Tasks leverages
this paradigm to investigate cognitive control to alcoholic stimuli.
The implemented procedure is based on:	

Amesa, S.L., Wong, S.W., Bechara, A., Cappelli, C., Dust, M., Grenard, J.L., & Alan W. Stacy, A.W. (2014).
Neural correlates of a Go/NoGo task with alcohol stimuli in light and heavy young drinkers.
Behavioural Brain Research, 274, 382–389.

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TASK DESCRIPTION	
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This is a basic go-nogo task. Participants are asked to press the spacebar for a go-stimulus (here: non-alcoholic beverages)
and withhold the response for nogo stimuli (here: alcoholic beverages).

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DURATION 
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the default set-up of the script takes appr. 15 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: 'alcoholgonogo_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.phase:						"practice" vs "test"
values.practiceBlocks:				running count of the number of practice blocks run
values.fixationDuration:			stores the sampled fixation duration (in ms) for the current trial																		
values.stim:						stores the item presented as go/nogo stimulus

response:							the participant's response (scancode of response button):
									57 = space bar
									0 = no response
									
correct:							accuracy of response: 1 = correct response; 0 = otherwise
latency: 							the response latency (in ms); measured from: onset of stimulus until response or trial time out	
list.ACC.mean:						proportion correct responses in the current block


(2) Summary data file: 'alcoholgonogo_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.practiceBlocks:				number of practice blocks run

values.failPractice:				1 (true)= participant failed practice (mean proportion correct during the last practice block < parameters.minPracticeACC);
									and test was skipped.
									0 (false)= participant passed practice
								
if test was run (Practice Failure = 0):								
expressions.numberGoTrials:			number of Go trials in the test block
expressions.numberNogoTrials:		number of Nogo trials in the test block

expressions.hitrate:				calculates the hitrate for the current block (hit = proportion of correctly hitting the spacebar for go-trials)
expressions.z_hitrate:				calculates the z-score for the hitrate. Adjustments are made if the hitrate = 0 (increased to 0.005) or 1 (decreased to 0.995)*

									
expressions.FArate*:				calculates the false alarm (commission) rate for the current block
									(FA = proportion of incorrectly hitting the spacebar for nogo-trials)
									=> the higher the commission rate, the lower cognitive control in the face of alcoholic stimuli	
										
expressions.z_FArate*:				calculates the z-score for the false alarm rate. Adjustments are made if the  FArate = 0 (increased to 0.005) or 1 (decreased to 0.995)*

expressions.dprime:					Computes d' (parametric measure of discriminability btw. signals and noise)
									=> Range (in this script): 
									-5.1516586840152740479 <= dprime <= 5.1516586840152740479 (=perfect performance)
									=> The higher the value, the better signals (non-alcoholic stimuli) were overall distinguished from noise (alcoholic stimuli)
									and thus the less distraction alcoholic stimuli presented
									(d' = 0: chance performance; negative d-primes: participant treated nontargets as targets and targets as nontargets)
									
expressions.meanRT_hits:			mean response times (ms) of hits during test trials
expressions.SDRT_hits:				standard deviation of hit latencies during test trials
expressions.medianRT_hits:			median response times (ms) of hits during test trials
expressions.minRT_hit:				minimum response time (ms) of hits during test trials (= fastest hit response)
expressions.maxRT_hit:				maximum response time (ms) of hits during test trials (= slowest hit response)

*Adjustments to z-scores as recommended by:
Gregg, A. & Sedikides, C. (2010). Narcissistic Fragility:
Rethinking Its Links to Explicit and Implicit Self-esteem, Self and Identity, 9:2, 142-161 (p.148)

* 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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1. Practice Block: (default settings - see section Editable Parameters for possible changes)
- max. 8 practice blocks
- each practice blocks runs 10 trials
	- if proportion correct of the current practice block is >= 0.9 (editable default setting), practice ends and the test phase commences
	- proportion correct after the 8th practice block is still < 0.9 (editable default setting), the task prematurely aborts
- errorfeedback (red X) during practice trials

2. Test Block: (default settings - see section Editable Parameters for possible changes)
- 200 trials total => 160 go trials: 40 nogo trials
- order of go and nogo trials is randomly determined
- no errorfeedback

Trial Timings:
fixation cross (variable duration)* -> 
stim presentation for max. 1500ms (if no response is given trial terminates after 1500ms after onset of stim;
if response is provided before 1500ms a fixation cross replaces the stim for the remainder of the 1500ms stim duration)-> 
next trial: fixation cross -> ...

*fixation cross timings: see list.fixationDurations under section Editable Lists
By default, the script selects randomly with replacement from durations 1000-3000 (steps of 100ms)
	
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STIMULI
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provided by Millisecond Software - can be edited under section Editable Stimuli

Note: the stimuli presented are based on the stimuli used by Amesa et al (2014).
Additional stimuli can be added to item.goStims and item.nogoStims

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INSTRUCTIONS 
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provided by Millisecond Software - can be edited under section Editable Instructions.
The instructions provided are not original to Amesa et al (2014).

Note: if additional stimuli are added to the design, 'gonogo_intro.htm' might have to be edited to 
display the added stimuli. 

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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:
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:

/fixationSize:					proportional height of fixation cross (proportional to canvas height) (default: 8%)
/picSize:						proportional height of images (proportional to canvas height) (default: 50%)

/numberOfTesttrials:			the number of test trials that should be run (default: 200)
									Note: if this number is changed, the new number should work with parameters 'goFrequency/nogoFrequency'
/goFrequency:					proportion of go trials to be run (default: 0.8)
/nogoFrequency:					proportion of nogo trials to be run (default: 0.2)
									Note: these proportions should result in integer numbers of trials given the numberOfTesttrials

/readyDuration:					the duration (in ms) of the 'get ready trial' (default: 2000ms)
/StimDuration:					the duration (in ms) of the image presentations (default: 1500ms)
									Note: participants have the entire StimDuration to respond

/maxPracticeBlocks:				the maximum number of practice blocks to be run (default: 8)
/trialsPerPracticeBlock:		the number of trials per practice blocks 
									Note: the number should be an even number, as the ratio of go:nogo trials = 1:1 during practice
/minPracticeACC:				the cut-off proportion correct during practice to stop the practice phase (default: 0.9)
									Notes: 
									- with 10 trials per block (default), participant can only make 1 error to pass the current 
									practice block
									- to remove the performance constraint, set minPracticeACC = 0. In this case, participants
									run one practice block and move on to the test regardless of practice performance.