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									PARAFOVEAL PRIMING
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software LLC
Date: 04-10-2012
last updated:  03-10-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-10-2020 Millisecond Software

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BACKGROUND INFO 	
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Scripts implements a Parafoveal Priming Procedure.This parafoveal priming task was used by Chartrand & Bargh (1996)
to subliminally activate participants' impression formation mode.

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

In this particular task, no actual target categories are used. The primes are presented either on the the left or
right side of the monitor at subliminal speed and covered by a 'mask' of random characters. The resulting 
visual 'flash' is to be categorized as being on the 'left' or 'right'. This procedure is used to simply activate
the priming categories.


This script uses the original text stimuli but could easily be adapted to a new purpose.
Please be aware that this script uses absolute stimulus sizing and thus depends on a minimum size monitor.
If the current monitor is deemed too small to run the current script, the script prematurely terminates.							

Reference:
											
Chartrand, T.L & Bargh, J.L. (1996). Automatic Activation of Impression Formation and Memorization Goals: 
Nonconscious Goal Priming Reproduces Effects of Explicit Task Instructions. 
Journal of Personality and Social Psychology, 71, 464-478.


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TASK DESCRIPTION	
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Categorize brief "flashes" on the screen as left or right flashes.

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DURATION 
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the default set-up of the script takes appr. 8 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: 'parafovealpriming_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.SOA:							stores the current SOA between onset of primes/noprimes

values.quadrant:					determines the screen quadrant in which the prime will appear
											1 = left upper
											2 = right upper
											3 = left lower
											4 = right lower
											
values.stimLocation:				"left" vs. "right"

response:							the participant's response: scancode of response
										30 = A (left response key)
										38 = L (right response key)
										
values.responseCategory:			"left" vs. "right"
correct:							the correctness of the response (1 = correct; 0 = incorrect)
latency: 							the response latency (in ms); measured from onset of stims
values.totalcorrect:				keeps a total of the correct responses


(2) Summary data file: 'parafovealpriming_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)

values.counttrials:					the number of test trials run									
values.totalcorrect:				keeps a total of the correct responses
expressions.propCorrect:			the proportion correct responses

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EXPERIMENTAL SET-UP 
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(1) 6 Practice Trials (with error feedback)
(2) 75 trials for condition "priming"/"nopriming": randomized order of the 4 different text stimuli, 
stimuli are selected at random with replacement
(3) 6 different Stimuli Onset Asynchronies (2000-7000ms); randomly selected with replacement
(4) 4 screen quadrants for the primes are selected randomly with replacement
(5) between participant design: half the participants get the prime words the other half the noprimes (see Chartrand & Bargh, 1996);
Assignment is done by "group number"
(6) Participants should have a monitor-eye distance of 99cm (see Chartrand & Bargh, 1996)	

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STIMULI
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(1) Practice Stimuli: in this script, the practice trials use unrelated stimuli
(2) Priming/noPriming conditions: use the original 4 text stimuli from Chartrand & Bargh (1996).
(3) Fixation Stimuli: 3 "+++ " in the middle of the screen
(4) Specifics for Stimuli Location/Size:
	(a) Most experimental stimuli sizes and screen positions in this script are absolute and NOT percentages of the monitor size
		and thus depends on a minimum sized monitor.
		If the current monitor is deemed too small to run the current script, the script prematurely terminates.
		The appropriate sizes are automatically calculated for the current monitor size.
	(b) the prime's center is 7.6cm away from the fixation symbols on the 45degree angle (135, 225, 315) (see Chartrand & Bargh, 1996).
		=> the middle of the prime is at 4degree visual angle (if participants sit 99cm away from screen)
		=> the boundary conditions for the size of the prime are 2degree-6degree visual angle (see Chartrand & Bargh, 1996)
	(c) Location of Primes: the location of primes in one of the four screen quadrants is randomly determined (Chartrand & Bargh, 1996,
		used one predetermined sequence)
	(d) Timing of Primes: the intervals between stimuli presentation is randomly determined (Chartrand & Bargh, 1996,
		used one predetermined sequence)
		Participants can respond to the "flashes" at any time during that interval, but are instructed to respond as fast and accurately as possible.
		Stimulus Onset Asynchrony (SOAs) are controlled by list.soas/list.soas_practice
	(e) Fontsize: this script uses Arial as it's a widely available font. The ideal fontsize in mm was determined using the longest stimuli
		used in this script: personality. If you use different stimuli than the ones provided you need to figure out the appropriate fontsize in cm.
		Go to FONTSIZE DETERMINATION and run block.fontsizedetermination under the experiment with the longest stimuli (-> text.longestword) in your stimuli set.
		Note the fontsize printed on the screen and use that size for parameters.fontheight_incm under EDITABLE VALUES.
	(f) Run block.determinefontsize under FONTSIZE DETERMINATION to make sure that the absolute distances used are correct for your monitor 

	
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INSTRUCTIONS 
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Instructions are not original to the task. They are provided by Millisecond Software
as htm pages and simple text elements and can be edited by changing
the provided html files and/or directly under 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:

distance_primefromfixation_inmm:		the diagonal distance of the prime from the fixation cross (measured in mm)

fontheight_inmm:						this is the fontheight in cm that makes the longest stimulus word fit
										fit snuggly into the boundaries from 2-6 degrees visual angle.
										If different stimuli are used go to FONTSIZE DETERMINATION and follow
										instructions