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Weapons ID Task - no response deadline
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 10-04-2017
last updated: 03-02-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 03-02-2022 Millisecond Software
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BACKGROUND INFO
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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 compatible
whereas the 'Black faces - tool' condition is incompatible but does not make any explicit pairing assumptions about the
'White faces' conditions.
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TASK DESCRIPTION
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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.
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DURATION
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the default set-up of the script takes appr. 7 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: 'weaponsidtask_raw*.iqdat'*
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
session: 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 such as feedback trials. Thus, trialnum
may not reflect the number of main trials run per block.
(parameter) 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
(parameter) 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)
18 = E = left
23 = I = right
responseCategory: 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'*
inquisit.version: Inquisit version run
computer.platform: the platform the script was run on (win/mac/ios/android)
startDate: date script was run
startTime: time script was started
subjectid: assigned subject id number
groupid: assigned group id number
sessionid: assigned session id number
elapsedTime: time it took to run script (in ms); measured from onset to offset of script
completed: 0 = script was not completed (prematurely aborted);
1 = script was completed (all conditions run)
(parameter) 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
(parameter) SOA: stimulus onset asynchrony (in ms) of prime and target (default: 500ms)
list.practiceACC.mean: stores the mean practice performance of the last/final 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_prime1target2.itemCount",
"list.ACC_prime2target1.itemCount", "list.ACC_prime2target2.itemCount": store the number of data points considered for summary statistics
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EXPERIMENTAL SET-UP
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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 (200ms) -> 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
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STIMULI
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http://bkpayne.web.unc.edu/research-materials/
- can be edited under section Editable Stimuli
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INSTRUCTIONS
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provided by Millisecond Software - they are not original to Payne (2001)
The instructions can be easily 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:
/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: 200ms)
/primeDuration: duration (in ms) of prime presentation (default: 200ms = 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:
/leftKey: the left response key (here: E)
/rightKey: the 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)
