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							SINGLE N-BACK TASK NON-ADAPTIVE (1-KEY VERSION)
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software LLC
Date: October, 2011
last updated: 10-14-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 10-14-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
This script implements the single-task version of the N-Back procedure as described in the following publication:

Jaeggi, Susanne M.; Studer-Luethi, Barbara; Buschkuehl, Martin; Su, Yi-Fen; Jonides, John; Perrig, Walter J. (2010). The 
relationship between n-back performance and matrix reasoning - implications for training and transfer. Intelligence, 38, 625–635.

Millisecond Software thanks Dr. Susanne Jaeggi for kindly providing original instruction materials, stimuli, as well as assistance!

This Inquisit script provides trials and instructions for single n-back tasks with random shapes (N = 0, N = 1, N = 2, N = 3, N = 4).
The script closely follows the procedure for nonadaptive single n-back tasks provided by Jaeggi et al (2010), Experiment 1,  and 
implements original instructions (or new ones closely following original ones) and stimuli kindly provided by the authors. 
Because the script closely follows the procedure  implemented by Jaeggi et al., the provided script runs N = 2, N = 3, N = 4 
trials. However, instruction materials, as well as code to run  N = 0, and N = 1 trials are also provided which can be implemented 
with minimal changes. 


											  *Task*
In the 1-key single n-back task, participants are shown a sequence of stimuli (here: a sequence of yellow shapes 
on a black background) and asked to indicate whether the currently presented stimulus fulfills the following criteria:

for N=0 trials*:
- is the shape the same as the first shape presented in the sequence? If so (it's a target), and press "A". If not, don't respond.

for N=1 trials:
- is the shape the same as the one that preceded it? If so (it's a target), and press "A". If not, don't respond.

for N=2 trials:
- is the shape the same as the one presented two trials before? If so (it's a target), and press "A". If not, don't respond.

for N=3 trials:
- is the shape the same as the one presented three trials before? If so (it's a target), and press "A". If not, don't respond.

for N=4 trials:
- is the shape the same as the one presented four trials before? If so (it's a target), and press "A". If not, don't respond.


*Note: The implementation for 0-nback tasks as well as instructions in this script differ from the procedure used by Jaeggi and collegues in her research.
Jaeggi and collegues used a pre-defined shape. In this script, the target shape is defined at runtime for each participant during the first trial. 
Participants are instructed to pay close attention to this first presentation and are warned that presentation time is short.


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

(1) Raw data file: 'SingleTaskNback_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 
values.N:						the type of N-back trial  
blockcode:						the name of the current block
values.TotalBlocks:				the total number of experimental blocks run
trialcode:						the name of the current trial
stimulusitem:					the file of the stimulus shown during a trial
stimulusnumber:					the item number of the stimulus shown during a trial
values.currenttarget:			the item number of the current target
response:						the response of the participant
correct:						the correctness of the response
latency:						how fast a participant responded within the 3000ms timeframe, if at all (in ms)
values.trial_Hit:				whether the response was a Hit (=1)
values.trial_FA:				whether the response was a False Alarm (=1)
values.trial_Miss:				whether the response was  Miss (=1)
values.trial_CR:				whether the response was a Correct Rejection ( = 1)
values.Hits:					the sum of Hits in a block
values.FalseA:					the sum of False Alarms in a block
values. Misses:					the sum of Misses in a block
values.CorrReject:				the sum of Correct Rejections in a block
values.TotalHits:				the sum of total hits across all experimental blocks
values.TotalFA:					the number of total false alarms across all experimental blocks
values.DV:						the proportion of (TotalHits - TotalFA)/number of experimental blocks

(2) Summary data file: 'SingleTaskNback_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)
values.TotalHits:				the sum of total hits across all experimental blocks
values.TotalFA:					the number of total false alarms across all experimental blocks
values.DV:						the proportion of (TotalHits - TotalFA)/number of experimental blocks

EXPERIMENTAL SET-UP:
- After instructions, participants receive 10 trials of practice per level N tested (here: N = 2, N = 3, N = 4) with possibility of more
- After practice, participants receive 3 blocks per level N tested (here: N = 2, N = 3, N = 4) 

Note: N-levels run
The levels and repetitions of N run by this script are controlled by list.nextN_practice and list.nextN under section Editable Lists.
By default, the list runs the selection items in sequence.
The levels of N can be easily altered (if altered for practice, the instruction slides used might have to be edited as well)


BLOCK information:
- Each single n-task block consists of 20+ trials using 8 different shapes. 
=> + trials are the N trials that cannot display target shapes yet (=start trials). Their numbers vary depending on N. The data collected during these 
		start trials are NOT included in performance counts for Correct Rejections/False Alarms.
=> Of the actual  20 experimental trials, 6 present a target and 14 do not. 
- The computer selects randomly 
a) whether it is a target trial or not and 
b) what shape to show if it is not a target trial

TRIAL information:
- Each trial presents the shape for 500ms and waits another 2500ms before presenting the next shape in the sequence.
- Participants have the entire 3000ms to respond by pressing "A" if they detect a target.


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:
/runPractice:					true (1): practice session runs (default); false (0): no practice is run		
/debugmode = 0					debugmode = 1: targetalerts are shown on screen, debugmode = 0, no targetalerts are shown (default)
/stimulusPresentationtime:		the presentation time (in ms) of the stimuli (default: 500ms)
/SOA:							the stimulus onset asynchrony in ms (default: 3000ms)- also response window	

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