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								*STEREOTYPE ACTIVATION - Priming Paradigm*
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 12-06-2016
last updated:  03-11-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-11-2020 Millisecond Software

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BACKGROUND INFO 	
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This script implements a variant of the Stereotype Activation Paradigm that measures stereotype
activation/inhibition using reaction times to words (either control words or stereotype-relevant words) that
follow the presentation of stereotype relevant imagery.

The procedure is closely related to a basic priming paradigm.
In general, priming procedures are simple response-timed binary categorization tasks of items from two target
categories  (e.g. positive vs. negative adjectives). Priming Procedures are based on the assumption that 
people respond faster if the target category was already 'mentally activated' by briefly presenting items 
(called 'primes') that are closely connected in one's mind. Thus, a person should be faster to quickly categorize
the target word 'good' as 'positive' after the brief presentation of the prime word 'ice-cream' than
after the brief presentation of the prime word 'famine'.

In this script, the basic priming procedure is 'spread out' across two seemingly unrelated tasks.
Task 1 presents the primes as images; Task 2 (a lexical decision task) presents the target words.

The implemented procedure is based on:

Moskowitz, G.B. &  Li, P.(2011). Egalitarian goals trigger stereotype inhibition: A proactive form of
stereotype control. Journal of Experimental Social Psychology, 47, 103–116.

Millisecond Software thanks Dr. Gordon Moskowitz and Joe Vitriol for their collaboration on this script!

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TASK DESCRIPTION	
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Participants work on 2 tasks that immediately follow one another:
Trial1 (Task1) -> Trial2 (Task2) -> Trial3 (Task1) -> Trial4 (Task2) -> etc.

(1) Priming Task: 
participants see (a) an image of a black or white, male face (the target primes) OR an object (control primes) 
either above or below the fixation cross and (b) opposite to the prime (either below of above the fixation cross), 
a pair of letter strings (either words or nonwords) that are either the same (e.g. 'matter' 'matter') or 
different (e.g. 'across' 'policy').
The task is to decide as fast as possible whether the letter strings are the 'same' or 'different' while 
trying to ignore the distracting image (cover story).

(2) Lexical Decision Task: after the priming task, participants view a string of letters (the target) and have to 
decide whether the letters form a word or not.

For the critical trials in this task, participants see Black and White male faces as primes that are paired
with a pair of identical nonwords in phase1. For task2, the Black and White primes (from task 1) 
each are followed by 8 stereotypic and 8 ctrl words.

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DURATION 
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the default set-up of the script takes appr. 12 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: 'stereotypeactivation_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 such as feedback trials. Thus, trialnum 
										may not reflect the number of main trials run per block.
									
values.test:						0 = practice phase; 1 = test phase
									
values.trialtype:					1 (critical) vs. 2 (filler)
values.phase:						1 (priming task); 2 (lexical decision task)
values.prime:						1 (Black faces); 2 (White faces); 3 (objects)
values.pairIdentity:				1 (same/identical); 2 (different) (phase1)
values.wordType:					1 = phase 1 WORDS; 2 = phase 1 NONWORDS
values.target:						1 (lexical decision task WORD); 2  (lexical decision task NON WORD)
values.valence:			 			0 (filler words in phase2), 1 (ctrl target words in phase2); 2 (stereotypic target words in phase2)
values.primeStim:					the currently presented prime stimulus
values.letterString1:				phase 1 letter string 1
values.letterString2:				phase 1 letter string 2
values.targetStim:					the currently presented target stimulus
values.targetStimNr:				the itemnumber of the presented target stimulus
values.prime_y:						stores the y-coordinate (in %) of the current prime
values.letterstring_y:				stores the x-coordinate (in %) of the current letter string pair
										Note: letterString1 sits 2% above this location, letterString2 sits 2% below this location
									
response:							the participant's response (scancode of response button)
									16 = Q
									25 = P
									57 = spacebar
									0 = no response
									
values.responseCategory:			stores the response classification 
										Phase 1: same or different
										Phase 2: word or nonword

correct:							the correctness of the response (1 = correct; 0 = incorrect)

latency: 							the response latency (in ms); 
									phase1: measured from onset of letter strings
									phase2: measured from onset of target words

(2) Summary data file: 'stereotypeactivation_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)

summary variables for critical trials only:
expressions.propcorrect:				overall proportion correct (Lexical Decision Task)
expressions.meanRT:						overall mean correct latency (in ms) (Lexical Decision Task)
expressions.SD:							standarddeviation of correct latencies (in ms)


expressions.propCorrect_Bprime_ctrl:			proportion correct (Lexical Decision Task) for ctrl words following a Black prime face
expressions.propCorrect_Bprime_stereotypic:		proportion correct (Lexical Decision Task) for stereotypic words following a Black prime face
expressions.propCorrect_Wprime_ctrl:			proportion correct (Lexical Decision Task) for ctrl words following a White prime face
expressions.propCorrect_Wprime_stereotypic:		proportion correct (Lexical Decision Task) for stereotypic words following a White prime face

expressions.corrmeanRT_Bprime_ctrl:				mean latency (in ms) of correct responses (Lexical Decision Task) for ctrl words following a Black prime face
expressions.corrmeanRT_Bprime_stereotypic:		mean latency (in ms) of correct responses (Lexical Decision Task) for stereotypic words following a Black prime face
expressions.corrmeanRT_Wprime_ctrl:				mean latency (in ms) of correct responses (Lexical Decision Task) for ctrl words following a White prime face
expressions.corrmeanRT_Wprime_stereotypic:		mean latency (in ms) of correct responses (Lexical Decision Task) for stereotypic words following a White prime face

corrected mean latencies: removes all latencies that are 3 standard deviations (expressions.SD) or more away from the overall mean (expressions.meanRT)

expressions.corrmeanRT_Bprime_ctrl:				corrected mean latency (in ms) of correct responses (Lexical Decision Task) for ctrl words following a Black prime face
expressions.corrmeanRT_Bprime_stereotypic:		corrected mean latency (in ms) of correct responses (Lexical Decision Task) for stereotypic words following a Black prime face
expressions.corrmeanRT_Wprime_ctrl:				corrected mean latency (in ms) of correct responses (Lexical Decision Task) for ctrl words following a White prime face
expressions.corrmeanRT_Wprime_stereotypic:		corrected mean latency (in ms) of correct responses (Lexical Decision Task) for stereotypic words following a White prime face

expressions.DiffScore_ctrl:			Difference in mean latencies for ctrl targets after B primes and W primes (corrmeanRT_Bprime_ctrl - corrmeanRT_Wprime_ctrl)
expressions.DiffScore_stereotypic:	Difference in mean latencies for stereotypic targets after B primes and W primes (corrmeanRT_Bprime_stereotypic - corrmeanRT_Wprime_stereotypic)
												=> positive scores: Inhibition
												=> negative scores: Activation/Facilitation								

							
* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions

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EXPERIMENTAL SET-UP 
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Practice: 16 trials total
- 8 trials with white faces: 
	4 with words in phase 2 (phase1: 1 with same words, 1 with different words, 1 with same nonwords, 1 with different nonwords)
	4 with nonwords (phase1: 1 with same words, 1 with different words, 1 with same nonwords, 1 with different nonwords)
- 8 trials with objects: 
	4 with words in phase 2 (phase1: 1 with same words, 1 with different words, 1 with same nonwords, 1 with different nonwords)
	4 with nonwords (phase1: 1 with same words, 1 with different words, 1 with same nonwords, 1 with different nonwords)

Error feedback during practice: red X presented for 500ms	
	

Test: 2 test blocks: each run 56 trials -> 112 trials total
- each block runs:
	* 16 critical trials:
		4 trials – Black faces paired with identical non-words in phase 1 and stereotypic words in phase 2
		4 trials -- White faces paired with identical non-words in phase 1 and stereotypic words in phase 2
		4 trials – Black faces paired with identical non-words in phase 1 and control words in phase 2
		4 trials -- White faces paired with identical non-words in phase 1 and control words in phase 2
	
	*40 filler trials with 28 non-words and 12 words in phase 2 (since the critical trials above had 16 words)
		12 white faces paired with non-words in phase 2 (4 same word, 4 different word, 4 different non-word in phase 1)
		12 objects paired with filler words (4 same word, 4 different word, 4 different non-word in phase 1)
		16 objects paired with non-words (4 same word, 6 different word, 6 different non-word in phase 1)

- the order of the trials is randomized
- all words/nonwords used in phase 2 are run twice

Trial Sequence:
Phase 1: FixationCross (2000ms) -> Image + Word Pair (presented for max.5000ms, above and below fixation cross) -> Response (Response Window: 1000ms, same as primeDuration) -> ITI: 400ms
Phase 2: Target Word/Nonword (stay on until Response or for max. 1500ms)

Note: by default, the vertical position of the primes are selected randomly with replacement for each trial.


Response Button Assignment:
same (Phase1) + word (Phase2): same response key
different (Phase1) + nonword (Phase2): same response key

The assignment of the two response buttons (default: Q (left), P (right) -> can be edited under section Editable Parameters)
is counterbalanced across groupnumbers.
odd groupnumbers: same/word -> Q; different/nonword -> P
even groupnumbers: same/word -> P; different/nonword -> Q

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STIMULI
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face stimuli: script uses placeholders as of now - pictures of black and white male faces can be downloaded from 
from the Chicago Face Database: http://faculty.chicagobooth.edu/bernd.wittenbrink/cfd/index.html
Go to section 'Editable Stimuli' and replace the file names for the face primes.

object stimuli as well as word/nonword stimuli: generously shared by Dr. Gordon Moskowitz

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INSTRUCTIONS 
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provided by Millisecond Software - can be edited under section "Editable Stimuli"

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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:

/leftKey:						the left keyboard scancode  (default: "Q")
/rightKey:						the right keyboard scancode (default: "P")

									
Timing Parameters:			
/fixationDuration:					the duration of the fixation cross (default: 2000ms)						
/maxPrimeDuration:					the max. duration of task 1 in ms (default: 1000ms)
/iti:								the duration of the intertrial interval btw. task 1 and task 2 in ms (default: 400ms)
/RW_phase2:							the response window for phase 2 (lexical decision task) in ms (default: 1500ms)


Sizing Parameters:
/fixationSize:						the proportional screen size of the fixation cross (default: 5%)
/pairFontsize:						the proportional screen size of the pair words in task 1 (default: 3%)
/targetFontsize:					the proportional screen size of the target string of letters in task 2 (default: 5%)
/primeSize:							the proportional screen size of the prime image (default: 30%)

/top_y:								the placement above the fixation cross in canvas screen percentages (50% = center) (default: 30%)
/bottom_y:							the placement below the fixation cross in canvas screen percentages (50% = center) (default: 70%)