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									GARNER INTERFERENCE TASK
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 03-05-2013
last updated:  03-09-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-09-2020 Millisecond Software
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BACKGROUND INFO 	
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This script implements a Garner Interference Paradigm that systematically varies the dimensions of
irrelevant information to study interference on the processing of relevant information.

The implemented task is based on:

Ridderinkhof, K. R., van der Molen, M. W., Band, P. H., & Bashore, T. R. (1997). Sources of interference 
from irrelevant information: A developmental study. Journal of Experimental Child Psychology, 65, 315–341.(Experiment1)

Ridderinkhof et al (1997) used this paradigm to study the development of attention in children.

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TASK DESCRIPTION	
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The two main dimensions used in this paradigm are tilt and color. Sometimes participants have to 
respond to the tilt of a line, in other cases they respond to the color, either of a surrounding box 
(in which case color and tilt are SEPARATED dimensions) or the color of the line itself 
(in which case color and tilt are INTEGRATED dimensions => more interference predicted). 
In addition, the change in color and tilt is systematically varied. The change can be:
a) correlated (either the dimensions would require the same response=congruent OR they would require opposite responses=incongruent)
b) orthogonal (= independent of each other => absence of a correlation)
c) neutral (= change happens only in one dimension but never in the other).
																					  
In each trial, participants view a box in the middle of the screen. Inside the box is a line that can be tilted to the left
or right.  The color of the box or the color of the line itself can change from red to blue.

Participants are instructed to pay attention to only one dimension (=relevant dimension)
a) the tilt of the line OR b) the color of either the box (separated condition) or the line itself (integrated condition) 
and ignore changes in the other (irrelevant) dimension as best as they can. 

The actual task they have to do is a simple categorization task: if the line tilts to the right, press a certain key. 
If the line tilts to the left, press another key. Same for the color tasks.

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DURATION 
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the default set-up of the script takes appr. 1 hour to complete

Notes:
1. The number of trials run per block can easily be reduced (see Editable Parameters)
2. To run a reduced number of blocks, change the blocks called by the 'expt' elements under section EXPERIMENT

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

(1) Raw data file: 'garnerinterferencetask_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. 
										
blockcount:							counts the testblocks run										
practice:							1 = practice blocks; 0 = experimental blocks
dimension:							target dimension: 1 = color; 2 = tilt
dim_config: 						1 = integrated; 2 = separated
variationtype:						1 = orthogonal; 2 = correlated; 3 = control
target:								"color1" vs. "color2" vs. "tilt1" vs. "tilt2"
responsekeycongruence:				0 = congruence doesn't apply; 1 = color and tilt response keys congruent; 2 = color and tilt response keys incongruent
response:							the participant's response (scancode of response button)
correct:							the correctness of the response (1= correct; 0 = error)
latency: 							the response latency (in ms); measured from onset of stimuli
ITI:								stores the current ITI (in ms)


(2) Summary data file: 'garnerinterferencetask_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)
																
									
overall_PropCorrect:				overall proportion correct (across all trials)
list.ACC.itemcount:					number of trials run
overall_RT:							mean latency (in ms) of correct responses (across all trials)
list.RT.itemcount:					the number of correct responses


propCorrect_separated:				proportion correct responses across all 'Separated' trials
meanrt_separated:					mean latency (in ms) of correct responses across all 'Separated' trials
propCorrect_Integrated:				proportion correct responses across all 'Integrated' trials

meanrt_integrated:					mean latency (in ms) of correct responses across all 'Integrated' trials
										=> Garner Interference would predict that you would see less interference in 'Separated' conditions
										than in 'Integrated' conditions; thus:
										higher proportion correct/faster mean latency in Separated Condition supports the presence 
										of Garner Interference in Integrated conditions
																				
										
										
propCorrect_control:				proportion correct responses across all 'Control' trials
meanrt_control:						mean latency (in ms) of correct responses across all 'Control' trials										
propCorrect_ortho:					proportion correct responses across all 'Ortho' trials
meanrt_ortho:						mean latency (in ms) of correct responses across all 'Ortho' trials	
propCorrect_correlatedC:			proportion correct responses across all Congruent 'Correlated' trials
meanrt_correlatedC:					mean latency (in ms) of correct responses across all Congruent 'Correlated' trials									
propCorrect_correlatedIC:			proportion correct responses across all INcongruent 'Correlated' trials

meanrt_correlatedIC:				mean latency (in ms) of correct responses across all INcongruent 'Correlated' trials
										=> The presence of Garner interference would predict that
										a) the (congruent) correlated dimension boosts performance 
										b) the orthogonal dimension hurts performance compared 
										to the control condition.

Separated summary scores for all individual conditions:
propCorrect_color_ortho_separated:	proportion correct responses across all separated, orthogonal color trials
meanrt_color_ortho_separated:		mean latency (in ms) of correct responses across all separated, orthogonal color trials
etc.	
	
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EXPERIMENTAL SET-UP 
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2 Dimensions (Color vs. Tilt), blocked-format x 
2 Dimensional Configurations (integrated vs. separated), blocked-format x
3 Variation Types (control, correlated, orthogonal), blocked-format

(A) Color vs. Tilt: color changes (red <-> blue) vs. changes in the tilt of the line (left <-> right)
if relevant dimension is color: the color of the unattended configuration (line or box) is yellow
if relevant dimension is tilt and no color changes should occur at all (control condition): box and line are purple
(red+blue -> purple)
	
(B) Integrated vs. Separated: color changes of the line itself vs. color changes of the box surrounding the line

(C) Control vs. correlated vs. orthogonal:
Control: only changes in the relevant dimension occur; the irrelevant dimension is held constant
Correlated: changes in the relevant dimension are tied to (dependent on) changes in the irrelevant dimension
	2 possible matches: 
		congruent  -> both changes require the same response or
		incongruent -> both changes require opposite responses
Orthogonal: changes in the relevant dimension are independent of changes in the irrelevant dimension
(half of the combinations are congruent vs. half are incongruent)

=> 16 different block types, tested all within-subjects

EXPERIMENTAL SET-UP
(a) 4 practice blocks (with error feedback)
(b) 12 experimental blocks: each block consisted of 48 trials; left/right responses occur equally often (no feedback)
Note: you can easily reduce the number of trials run per block (see Editable Parameters)
(c) A rest block in between each block

Notes:
1. The number of trials run per block can easily be reduced (see Editable Parameters)
2. To run a reduced number of blocks, change the blocks called by the 'expt' elements under section EXPERIMENT


RESPONSE KEYS/STIMULI:
Use of response keys (default: Y and B keys) is counterbalanced across participants. Assignment is done by groupnumber to 
any of the 4 possible key combination conditions.

EVEN groupnumbers align the tilt with the location of the left and right response buttons.
ODD groupnumbers use the opposite location.

!Note: The location of the (default) response keys (right "L" or left "A" on the keyboard) could introduce the potentially 
unwanted variable  "compatibility with tilt direction". 
To avoid, use 
(a) different response keys (change under Editable Parameters, e.g. Y and B)
(b) different stimuli: A set of possible alternative stimuli is provided under section Editable Stimuli -> item.lines
The set of alternative stimuli are Vs that differ in whether they are upside down or rightside up (replacing the direction
of left vs right). The composite stimulus for the color control condition is a diamond as it contains both V directions.

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INSTRUCTIONS 
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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:

/line_fontheight:				sets the height of the lines in % screen height (default: 20%)

/responsekeyleft:				the left response key (default: "A")
/responsekeyright:       		 the right response key (default: "L")

/color1:						sets the first target color (here: red)
/color2:						sets the second target color (here: blue)
/alternativecolor1:				sets the first alternative color (here: yellow)

/alternativecolor2:				sets the second alternative color (here: purple), used in control
								condition when color is held constant and only tilt is changing

/responsetimeout:				sets how much time participants have to respond in ms (here: 5000ms)

/regularresttime:				rest time after each block in ms (default: 60000s)
/prolongedresttime:				rest time during specified long rest blocks in ms (default: 300000)
/prolongedrest:					determines after how many blocks a prolonged rest block should be given (default:10)


/nrTrialsPerPracticeblock:		the number of trials per practice block that should be run (default: 48)
									Note: 48 is the maximum that will run
									
/nrTrialsPerTestblock:			the number of trials per test block that should be run (default: 48)
									Note: 48 is the maximum that will run