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								Weapons ID Task - no response deadline
SCRIPT INFO

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 10-04-2017
last updated: 10-11-2017 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Script Copyright © 10-11-2017 Millisecond Software


BACKGROUND INFO 

											*Purpose*
This script implements the Weapon ID Task as described in:

Payne, B.K. (2001). Prejudice and Perception: The Role of Automatic and Controlled Processes
in Misperceiving a Weapon. Journal of Personality and Social Psychology, Vol. 81, 181-192.

http://bkpayne.web.unc.edu/research-materials/

Notes: 
(1) This script runs the Weapon ID Task without a response deadline.
(2) This script is written in such a way, that primes and targets can easily be substituted (see section Editable Stimuli).
(3) This script template makes the following prime-target compatibility-assumptions* (relevant if primes and targets are changed):
compatible pairings: prime1-target1; prime2-target2
incompatible pairings: prime1-target2; prime2-target1

*Payne (2001): the original Weapons ID Task explicitly states that the 'Black faces - weapons' condition is incompatible 
whereas the 'Black faces - tool' condition is incompatible but does not make any explicit pairing assumptions about the 
'White faces' conditions. 


											  *Task*
Categorization task of images as gun (target1) or tool (target2) after seeing either a black face (prime1) or 
a white face (prime2). The targets (gun or tool) are masked after 200ms (default)
and participants have to press one key if the target was a gun ('E') and another if it was a tool (e.g 'I').
In this script, there is no response deadline for the response.




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

(1) Raw data file: 'weaponsidtask_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) 
									
/primeDuration:					duration (in ms) of prime presentation (default: 500ms = SOA)
									!Note: if primeDuration was set to be longer than SOA, the script automatically set the primeDuration = SOA
/SOA:							stimulus onset asynchrony (in ms) of prime and target (default: 500ms)																	

/compatibility:					1 = prime-target pairing compatible; 0 = prime-target pairing incompatible
									This script template makes the following prime-target compatibility-assumptions
									compatible pairings: prime1-target1; prime2-target2
									incompatible pairings: prime1-target2; prime2-target1															
/primeType:						here: "black" vs. "white"
/targetType:					here: "GUN" vs. "TOOL"
/prime:							stores the currently presented prime image
/target:						stores the currently presented target image
response:						the participant's response: scancode of response button (default: 18 = E; 23 = I)
values.response:				translation of scancode into response category (here: "tool", "gun")
correct:						accuracy of response: 1 = correct response; 0 = otherwise
latency: 						the response latency (in ms); measured from: onset of target until response
list.practiceACC.mean:			stores the mean practice performance of the current block  
/countPracticeBlocks:			stores the number of practice blocks run

								
(2) Summary data file: 'weaponsidtask_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)

/primeDuration:					duration (in ms) of prime presentation (default: 500ms = SOA)
									!Note: if primeDuration was set to be longer than SOA, the script automatically set the primeDuration = SOA
/SOA:							stimulus onset asynchrony (in ms) of prime and target (default: 500ms)																	

list.practiceACC.mean:			stores the mean practice performance of the last practice block  
/countPracticeBlocks:			stores the number of practice blocks run
/advance:						0 = no, script was aborted after practice due to low categorization performance during practice
								1 = participant advanced to test session
				

Note: the following summary variables are based on ALL responses regardless of accuracy and timing constraints
/propCorrect_all:				proportion correct of ALL trial responses
/meanRT_all:					mean latency of ALL trials
/efficiency:					proportion correct of all trial responses in relation to the average response time
								= propCorrect_all/meanRT_all

!Note: for the remaining summary variables
only responses with minRT <= latencies <= maxRT are considered for accuracy and latencies statistics

/propCorrect:					overall proportion correct
/meanRT:						overall mean latency (in ms) of correct responses 
/meanlnRT:						mean of the ln-transformed latencies of correct responses across all conditions
/ACC_prime1_target1:			proportion correct responses in prime1 -> target1 (here: black -> gun condition)
/RT_prime1_target1:				mean latency (in ms) of correct responses in prime1 -> target1 (here: black -> gun condition)	
/lnRT_prime1_target1:			mean of the ln-transformed latencies of correct responses in prime1 -> target1 (here: black -> gun condition)								
/ACC_prime1_target2:			proportion correct responses in prime1 -> target2 (here: black -> tool condition)
/RT_prime1_target2:				mean latency (in ms) of correct responses in prime1 -> target2 (here: black -> tool condition)
/lnRT_prime1_target2:			mean of the ln-transformed latencies of correct responses in prime1 -> target2 (here: black -> tool condition)
/ACC_prime2_target1:			proportion correct responses in prime2 -> target1 (here: white -> gun condition)
/RT_prime2_target1:				mean latency (in ms) of correct responses in prime2 -> target1 (here: white -> gun condition)
/lnRT_prime2_target1:			mean of the ln-transformed latencies of correct responses in prime2 -> target1 (here: white -> gun condition)
/ACC_prime2_target2:			proportion correct responses in prime2 -> target2 (here: white -> tool condition)
/RT_prime2_target2:				mean latency (in ms) of correct responses in prime2 -> target2 (here: white -> tool condition)
/lnRT_prime2_target2:			mean of the ln-transformed latencies of correct responses in prime2 -> target2 (here: white -> tool condition)

list.ACC_prime1target1.itemcount-list.ACC_prime2target2.itemcount: stores the number of data points considered for summary statistics

* 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

Design:
2 prime types (here: male black faces vs. male white faces) X 2 target types (here: tool vs. gun), tested within participants

1. Practice: learning to categorize the targets correctly
- minimum of 4 blocks of 12 trials (=all 12 targets), order of targets is randomized
If proportion correct is < targetPracticePerformance (0.90, default) during the last practice block, additional practice blocks
automatically start until the criterium of targetPracticePerformance is achieved 
(or until the max. number of practice blocks has run; default: 10)
- feedback is provided: if incorrect response -> the image of the target is presented again for further study
- participants only advance to the test if they reach targetPracticePerformance during the last practice block run

Note: Payne (2001) presented 48 practice trials without a specified 'targetPracticePerformance' that had to be reached 

Practice Trial Sequence:
target (200ms) -> mask (until response) -> feedback (reinforces learning by presenting the same target once more for error response) until spacebar press -> ITI (500ms)


2. Test
- 192 trials = each of the four 'prime type x target type' combinations runs 48 trials (order of trials is randomized)
	* per 'prime type x target type' combination: 
	- each prime is presented 4 times, order is randomized
	- each target is presented 8 times, order is randomized
	- Pairing:
	each randomly selected face prime is paired with a randomly selected target of the appropriate category
	(no constraints applied on the random pairing of primes and targets)
	Example: in trial.prime1_target2: each of 12 black face primes are randomly paired with a tool target

Test Trial Sequence:
prime (500ms) -> target (200ms) -> mask (until response) -> ITI (500ms)


Key Assignment:
key assignment to tool/gun is counterbalanced by groupnumber
odd groupnumbers: 'gun' with right key on keyboard ("E") vs. 'tool' with left key on keyboard ("I")	
even groupnumbers: 'tool' with right key on keyboard ("E") vs. 'gun' with left key on keyboard ("I")	

Estimates of Controlled/Automatic Components:
In this script the focus is on gun (target1) identifications following different primes
congruent condition: prime1-target1 pairs (black faces preceding guns) => allows the estimate of hit rate for gun identifications 
incongruent condition: prime1-target2 pairs (black faces preceding tools) => allows the estimate of false alarm rate for gun identification

	
STIMULI
http://bkpayne.web.unc.edu/research-materials/
 - can be edited under section Editable Stimuli

 
INSTRUCTIONS
provided by Millisecond Software - they are not original to Payne (2001)
The instructions can be easily edited under section Editable Instructions


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:

/minPracticeBlocks:	the minimum number of practice blocks run (default: 4)
/maxPracticeBlocks: the maximum number of practice blocks run before the script aborts because categorization performance is too low (default: 10)
/targetPracticePerformance:		proportion correct that participant has to reach during last practice block to continue on to task (default: 90%)
								Note: to eliminate a limit, set targetPracticePerformance = -1
					
/SOA:				stimulus onset asynchrony (in ms) of prime and target (default: 500ms)
/primeDuration:		duration (in ms) of prime presentation (default: 500ms = SOA)
					!Note: if primeDuration is set to be longer than SOA, the script automatically sets the primeDuration = SOA
/targetDuration:	duration (in ms) of target before it is replaced by a mask (default: 200ms)
/iti:				duration (in ms) of intertrial interval after response and before a new trial starts (default: 500ms)
/readyDuration:		duration (in ms) of the 'get ready' trial (default: 5000ms)

/primeSize:			the size of the prime pictures proportional to canvas height (default: 40%)
/targetSize:		the size of the target pictures proportional to canvas height (default: 20%)

Responsekeys: see tool -> Keyboard scancodes 
/leftKey:			scancode of the left response key (default: 18)
/leftKeyLabel:		label of left response key (here: E)
/rightKey:			scancode of the right response key (default: 23)
/rightKeyLabel:		label of right response key (here: I)
Note: the assignment of left and right response key to tool vs. gun is counterbalanced by groupnumber
odd groupnumbers: left response key is used to identify gun, right response key is used for tool
even groupnumbers: right response key is used to identify gun, left response key is used for tool

RT cut-offs for summary statistics:
/minRT:				latencies < minRT are not considered for summary statistics (default: 100ms) 	
/maxRT:				latencies > maxRT are not considered for summary statistics	(default: 1000ms)

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