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									*SUBLIMINAL PRIMING PROCEDURE*
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 04-25-2013
last updated:  03-12-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-12-2020 Millisecond Software

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BACKGROUND INFO 	
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This script implements a Subliminal Priming Procedure.

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. For example, 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'. Priming Procedure can thus be used to study 
implicit attitudes. Faster reaction times to targets after primes from a specific category are interpreted 
as indicative of an existing  relationship/association between  the categories in the person's mind.

If the primes are presented with a temporal duration that can be consciously processed, the primes are
called 'supraliminal'. If the duration of the primes is so short that they are outside one's conscious 
awareness the primes are called 'subliminal'. This script uses subliminal primes.

In this script, the primes that are used have been previously be conditioned to be a positive or a negative
condition stimulus (CS). Without the conditioning the default primes used in this script have likely
no affect on target categorization.

Reference:

Michael A. Olson, M.A. & Fazio, R.H. (2002). Implicit acquisition and manifestation of classically 
conditioned attitudes. Social Cognition, 20, 89-103.

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TASK DESCRIPTION	
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After seeing an alphanumeric mask (that is very briefly "interrupted" by a subliminal prime), 
participants are asked to categorize adjectives as positive or negative.
Two primes are used that have been conditioned to be a positive and a negative CS in a prior study
(for more info on the conditioning part of the study see Olson & Fazio, 2002).

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DURATION 
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the default set-up of the script takes appr. 3 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: 'subliminalpriming_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)
display.refreshrate:				the vertical refreshrate of the current monitor
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.selectprime1:				store the assignment (itemnumber) of primes to prime1 and prime2
values.selectprime2:
values.targetindex:					stores the targetindex of the current target adjective

response:							the participant's response (scancode of response button)
										30 = A
										38 = L
										57 = spacebar
										0 = no response
										
correct:							the correctness of the response (1 = correct; 0 = incorrect)
latency: 							the response latency (in ms); measured from onset of target word

							
(2) Summary data file: 'subliminalpriming_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)
									
display.refreshrate:				refreshrate of monitor									
									
expressions.propcorrect:				overall proportion correct (test trials only)
expressions.meanRT:						overall correct mean latency in ms (test trials only)

expressions.propcorrect_prime1pos:		proportion correct in Prime1-Positive Adjective Pairings
expressions.propcorrect_prime1neg:		proportion correct in Prime1-Negative Adjective Pairings
expressions.propcorrect_prime2pos:		proportion correct in Prime2-Positive Adjective Pairings
expressions.propcorrect_prime2neg:		proportion correct in Prime2-Negative Adjective Pairings

expressions.meanrt_prime1pos:			correct mean latency (in ms) in Prime1-Positive Adjective Pairings
expressions.meanrt_prime1neg:			correct mean latency (in ms) in Prime1-Negative Adjective Pairings
expressions.meanrt_prime2pos:			correct mean latency (in ms) in Prime2-Positive Adjective Pairings
expressions.meanrt_prime2neg:			correct mean latency (in ms) in Prime2-Negative Adjective Pairings

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EXPERIMENTAL SET-UP 
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* 2 primes (Shelder vs. Metapod) x 2 adjective valence (positive vs. negative) 
=> 4 experimental trial conditions
* 16 positive and 16 negative adjectives

Blocks:
1) Practice Block: runs 16 trials (8 with positive and 8 with negative adjectives) with a pseudo "prime" 
to achieve a similar "look" as the experimental trials (Olson and Fazio (2002) may not have used a pseudo "prime")
2) 2 Experimental Blocks of 32 trials: 
- across all 64 experimental trials, each prime is paired once with each of the 32 adjectives.
- all 32 adjectives are sampled ONCE during each block (no repeats); see LISTS for more details

Trials: stimulus durations taken from Olson & Fazio (2002)
- pre-mask consisting of a string of alphanumeric characters for 56ms
- followed by a prime for 28ms
- post-mask (same alphanumeric string) for 42ms
- 98ms later: adjective
=> timeline: 0ms: premask; 56ms: prime; 84ms: postmask; 126ms: postmask eraser; 224ms: adjective

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STIMULI
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most of the stimuli used in this script are not the originals; 
they can be edited under section Editable Stimuli

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INSTRUCTIONS 
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the instructions used in this script are not originals;
they 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:

/fontheight:						sets the height of the font for all text stimuli (default: 5%)

Responsekeys:						good/bad response keys get assigned by groupnumber	
										more info under EXPERIMENT
										
/responsekey_left:					the left responsekey (default: "A")
/responsekey_right:					the right responsekey (default: "L")