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										Alcohol Go/Nogo Task
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 12-21-2017
last updated: 02-14-2018 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Script Copyright © 02-14-2018 Millisecond Software


BACKGROUND INFO 

											*Purpose*
This script implements a basic Go/Nogo Paradigm with alcohol related stimuli based on the procedure 
described by:


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.


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



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

(1) Raw data file: 'alcoholgonogo_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) 
/phase:							"practice" vs "test"
/practiceBlocks:				running count of the number of practice blocks run
/fixationDuration:				stores the sampled fixation duration for the current trial																		
/stim:							stores the item presented as go/nogo stimulus
response:						the participant's response
correct:						accuracy of response: 1 = correct response; 0 = otherwise
latency: 						the response latency (in ms); measured from:
list.ACC.mean:					proportion correct responses in the current block


(2) Summary data file: 'alcoholgonogo_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)

/practiceBlocks:				running count of the number of practice blocks run
/failPractice:					1 = participant failed practice (mean proportion correct during the last practice block < parameters.minPracticeACC);
								and test was skipped.
								0 = participant passed practice
								
if test was run:								
/numberGoTrials:				number of Go trials in the test block
/numberNogoTrials:				number of Nogo trials in the test block
/hitrate:						calculates the hitrate for the current block (hit = proportion of correctly hitting the spacebar for go-trials)
/FArate:						calculates the false alarm rate for the current block (FA = proportion of incorrectly hitting the spacebar for nogo-trials)
/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)*
/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)*
/dprime:						Computes d' (parametric measure of discriminability btw. signals and noise)
/meanRT_hits:					mean response times (ms) of hits during test
/SDRT_hits:						standard deviation of hit latencies 
/medianRT_hits:					median response times (ms) of hits
/minRT_hit:						minimum response times (ms) of hits
/maxRT_hit:						maximum response times (ms) of hits

*Adjustments 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


EXPERIMENTAL SET-UP

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)
	

STIMULI
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

INSTRUCTIONS
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. 


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:

/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.

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