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									DICHOTIC LISTENING TASK (DIGITS)
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 04-03-2012
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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This script implements a variant of the dichotic listening task to study selective auditory attention.
The implemented procedure uses digits.

Reference:

Koch, I., Lawo, F., Fels, J.  & Vorlaender, M. (2011). Switching in the Cocktail Party: Exploring Intentional 
Control of  Auditory Selective Attention. Journal of Experimental Psychology: HPP, 37, 1140 - 1147

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TASK DESCRIPTION	
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Participants listen to 2 digits (1-9, no 5) simultaneously played in the left and the right ear, one spoken by 
a female  and the other by a male voice. In each trial a colored cue (here: @) signals which of the two genders 
presents the target digit.
The task is to decide if the target digit is less than or greater than 5.

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DURATION 
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the default set-up of the script takes appr. 28 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: 'dichoticlistening_digits_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. 
										
, 
, parameters., , parameters.colorname2,
values., values., values., values., values.gender_right, 
values.digit_left, values.digit_right, values.left_index, values.right_index,
response, correct, latency										

group:								color assignments to female/male
									1: female = yellow; male = green
									2: female = green; male = yellow
										
parameters.smallerkey/largerkey:	the scancode for the "smaller"/"larger" keys
parameters.colorname1/colorname2:	hold the NAME of the two colors

blockcount:							counts the experimental blocks run

expcondition:						the experimental condition run:
										0 = starttrial; 
										1 = switch-congruent (sc); 2 = switch-incongruent (sic); 
										3 = repeat-congruent (rc); 4 = repeat-incongruent (ric)
										
genderattention:					1 = pay attention to female voice; 
									2 = pay attention to male voice
								
gender_left/gender_right:			the gender of the voice in the left/right ear, 1 = female; 2 = male
digit_left/digit_right:				the digits to play in each ear
left_index/right_index:				the index number of the left/right soundfile to be played

response:							the participant's response (e.g. scancode of response button)
										16 = Q (left)
										25 = P (right)
										
correct:							the correctness of the response (1=correct; 0 = error)
latency: 							the response latency (in ms)


(2) Summary data file: 'dichoticlistening_digits_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)

propCorrect_overall:				overall proportion correct across the 4 experimental conditions
expressions.meanRT_overall:			mean correct response time (in ms) across the 4 experimental conditions

propCorrect_SC:						proportion correct in condition sc (shift, congruent)
meanRT_SC:							mean correct response time (in ms) in condition sc (shift, congruent)
propCorrect_SIC:					proportion correct in condition sic (shift, incongruent)
meanRT_SIC:							mean correct response time (in ms) in condition sic (shift, incongruent)
propCorrect_RC:						proportion correct in condition rc (repeat, congruent)
meanRT_RC:							mean correct response time (in ms) in condition rc (repeat, congruent)
propCorrect_RIC:					proportion correct in condition ric (repeat, incongruent)
meanRT_RIC:							mean correct response time (in ms) in condition sic (repeat, incongruent)

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EXPERIMENTAL SET-UP 
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* 2 levels of auditory attention switch (switch vs. repeat) x 2 levels of congruence of digits (congruent vs. incongruent)
=> 4 experimental conditions
 (1) Auditory Attention Switch: tested within
Switch: if participant had to pay attention to male (female) channel in previous trial, participant is asked to pay attention to female
(male) channel for the current trial
Repeat: pay attention to the same gender in the current trial
(2) Congruence: tested within
Congruent: both digits are less (greater) than 5
Incongruent: one digit is greater and one is less than 5
* Color Assignments counterbalanced by groupnumber

BLOCKS:
(1) Experimental: 4 blocks
* each block runs 1 starttrial + 144 experimental trials (36 per experimental condition)
(starttrial is excluded from analyses, it cannot be one of the 4 experimental conditions as it can neither switch nor repeat)
(2) Practice: short version of the Experimental condition: 1 starttrial + 24 experimental trials (no data recorded)

TRIAL COMBOS: 
trial.switch_congruent, trial.switch_inconcruent, trial.repeat_congruent, trial.repeat_incongruent (trial.starttrial)-> trial.response

* present a large @ sign in green and yellow (default) that signal to pay attention to male or female voice (counterbalanced for color-gender assignment) 
(by default there is a 800ms pretrialpause before the cue comes on, and the cue stays on for 500ms before the digits are spoken)
* determine gender to be attended according to experimental condition
* randomly assign gender to the left and right channel
* randomly select a digit for the left ear and depending on experimental condition, randomly select from the congruent or 
incongruent options for the right ear (excluding same digits for congruent condition, e.g. you cannot have "2" spoken in the left and right ear)
* randomly select one of the three soundfiles for each ear depending on digit and assigned gender
* sum up reaction times of correct responses and calculate corresponding mean (DV), separately for each condition
These data are recorded in the summary data file.
* errorfeedback for 1000ms

!!!NOTE!!!: Koch et al (2011) not only excluded the reaction times of the starttrials and reaction times of incorrect trials but also excluded
reaction time of trials with reaction times that exceed 3STDs of the mean. This script simply excludes data from starttrials as well as
reaction times of incorrect trials.

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STIMULI
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*3 soundfiles per digit per gender (3 different voices) = 2 * 3 * 9 = 54 (minus 6 soundfiles for digit 5 that are included for 
algorithm purposes only)
!!!NOTE!!!!: the script has the necessary set-up to support using 3 sounfiles per gender per digit, however, at this point only 
one actual soundfile per gender per digit is included. To add the remaining soundfiles go to Stimuli Item.digitsounds.

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INSTRUCTIONS 
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provided by Millisecond Software  in the form on images- can be edited under section Editable Instructions

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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:

cuepresentation:					the duration of the cue before the soundfiles are played in ms (default: 500)
pre_cuepresentation:				the pause before the cue comes on in ms (default: 800)
smallerkey/largerkey:				the scancode for the "smaller" (Q)/"larger" keys (P)

color_1/color_2:					the colors associated with gender
										Note: Assignment is counterbalanced by groupnumber
										
colorname1/colorname2:				string variables that holds the NAME of the two colors

Note: if you change the colors and/or key scancodes, you need to make appropriate changes to
item.intros