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									DUAL N-BACK TASK - nonadaptive
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software LLC
Date: October, 2011
last updated: 10-24-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 10-24-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
This Inquisit script provides trials and instructions for DUAL n-back tasks with blue squares in 8 different screen locations as well as 
spoken Roman letters.
The script closely follows the procedure for non-adaptive DUAL n-back tasks provided by Jaeggi et al (2010), Experiment 1, 
and implements original instructions (or new ones closely following the 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, different levels of N can be run with simple code changes.

Reference:
Jaeggi S.M, Studer-Luethi, B., Buschkuehl, M, Su, Y.-F., Jonides, J., Perrig, W.J. (2010). The relationship between n-back performance
and matrix reasoning - implications for training and transfer. Intelligence, 38, 625-635.

Millisecond Software LLC thanks Jaeggi et al (2010) for kindly providing original instruction materials, stimuli, as well as ample assistance!


											  *Task*
In Dual n-back tasks, participants are presented with two sequences of stimuli in two modalities at the same time
Here:
a) VISUAL: a random sequence of blue squares that can be presented in 8 different locations on the screen  and 
b) AUDITORY: a random sequence of 8 spoken Roman letters 
In each trial one visual and one auditory stimulus are presented and participants are asked to indicate whether the currently presented stimuli
fulfill the following criteria:

for N=0 trials*:
- is the location of the square the same as the one first presented? If so (it's a target), and press "A". If not, don't press "A".
- is the letter the same as the one presented first? If so (it's a target), and press "L". If not, don't press "L".

for N=1 trials:
- is the location of the square the same as the one  in the previous trial? If so (it's a target), and press "A".  If not, don't press "A".
- is the letter the same as the one in the previous trial? If so (it's a target), and press "L". If not, don't press "L".

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

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

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

*The set-up for 0-nback tasks as well as instructions in this script differ from the procedure used by Jaeggi and collegues in her earlier research.
Jaeggi and collegues used a pre-defined location and a pre-defined letter. In this script, the target location and target letter are defined
at runtime for each participant during the first trial. Participants are instructed to pay close attention to this first presentation.


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

(1) Raw data file: 'DualTaskNBack_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:					first shown stimulus (=square)
values.v_position:				contains the position of the current square
									(1 = (25, 25), 2 = (50, 25), 3 = (75, 25), 4 = (25, 50), 5 = (75, 50), 6 = (25, 75), 7 = (50, 75), 8 = (75, 75))
values.v_currenttarget:			the position number of the current target shape
stimulusitem:					second presented stimulus (=sound)
values.a_stimnumber:			contains item number of the currently presented sound
values.v_currenttarget:			the item number of the current target sound
values.1response:				the value of the first response (if any)
values.2response:				the value of the second response (if any)
correct:						1 = if correct response, 0 = otherwise
values.1latency:				the latency value of 1response (in ms)
values.2latency:				the latency value of 2response (in ms)
latency:						the latency value of the last response made (if any), MAX=3000 (=no response made)
values.trial_Hitv:				trial Hit for visual stimulus (1 = hit, 0 = no hit) (visual Hit: any trial response -either the first or the second- for a visual target)
values.trial_Missv:				trial Miss for visual stimulus (1 = miss, 0 = no miss) (visual Miss: no trial response for a visual target if a visual target was presented)
values.trial_CRv:				trial Correct Rejection  for visual stimulus (1 = CR, 0 = no CR) (visual CR: no trial response for a visual target if no visual target was presented)
values.trial_FAv:				trial False Alarm for visual stimulus (1 = FA, 0 = no FA) (visual FA: any trial response for visual target -either the first or the second- if no visual target was presented)
values.trial_Hita:				trial Hit for auditory stimulus (1 = hit, 0 = no hit) (auditory Hit: any trial response -either the first or the second- for an auditory target)
values.trial_Missa:				trial Miss for auditory stimulus (1 = miss, 0 = no miss) (auditory Miss: no trial response for an auditory target if an auditory target was presented)
values.trial_CRa:				trial Correct Rejection  for auditory stimulus (1 = CR, 0 = no CR) (auditory CR: no trial response for an auditory target if no auditory response was presented)
values.trial_FAa:				trial False Alarm for auditory stimulus (1 = FA, 0 = no FA) (auditory FA: any trial response for an auditory target -either the first or the second- if no auditory response was presented)
values.v_Hits:					the number of Hits for visual modality 
values.v_FalseA:				the number of False Alarms for visual modality
values. v_Misses:				the number of Misses for visual modality
values.v_CorrReject:			the number of Correct Rejections for visual modality
values.a_Hits:					the number of Hits for auditory modality
values.a_FalseA:				the number of False Alarms for auditory modality
values. a_Misses:				the number of Misses for auditory modality
values.a_CorrReject:			the number of Correct Rejections for auditory modality
values.v_TotalHits:				the number of total hits across all experimental blocks for the visual modality
values.a_TotalHits:				the number of total hits across all experimental blocks for the auditory modality
values.v_TotalFA:				the number of total false alarms across all experimental blocks for the visual modality
values.a_TotalFA:				the number of total false alarms across all experimental blocks for the auditory modality
values.DV:						the proportion of ((v_TotalHits - v_TotalFA) + (a_TotalHits - a_TotalFA)/2) /number of total experimental blocks

(2) Summary data file: 'DualTaskNBack_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.v_TotalHits:				the number of total hits across all experimental blocks for the visual modality
values.a_TotalHits:				the number of total hits across all experimental blocks for the auditory modality
values.v_TotalFA:				the number of total false alarms across all experimental blocks for the visual modality
values.a_TotalFA:				the number of total false alarms across all experimental blocks for the auditory modality
values.DV:						the proportion of ((v_TotalHits - v_TotalFA) + (a_TotalHits - a_TotalFA)/2) /number of total experimental blocks


EXPERIMENTAL SET-UP
(1) Dual n-back Experiment (non-adaptive) information:
- After instructions, participants receive 10 trials of practice per level N tested (here: N = 2, N = 3, N = 4) - with possibility of repeat.
- 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 might have to be edited as well)


(2) Dual n-back BLOCK information:
- Each dual n-task block consists of 20 + trials. 
=> + 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, 4 present a visual target only, 4 present an auditory target only, 2 present both targets
and 10 present no targets at all
- The computer selects randomly 
a) which kind of trial 
b) what letter/ square location to use if it is not a target

(3) Dual n-back TRIAL informations:
- Each trial presents the square/letter for 500ms and waits another 2500ms before presenting the next square/letter in the sequence.
- Participants have the entire 3000ms to respond by pressing "A", "L", or both if they detect a target or two.

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, target alerts are presented
								Debugmode = 0, target alerts are turned-off (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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