Return to the Parafoveal Priming page

Script Author: Katja Borchert, Ph.D. ( for Millisecond Software LLC
Date: 04-10-2012
last updated: 01-25-2016 by K.Borchert ( for Millisecond Software LLC

Copyright © 01-25-2016 Millisecond Software


Scripts implements the Parafoveal Priming Procedure described in:											
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.

The parafoveal priming task was used by Chartrand & Bargh (1996) to subliminally activate participants' impression formation mode.
This script uses the original text stimuli but could easily be adapted to a new purpose.

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

The default data stored in the data files are:

(1) Raw data file: 'ParafovealPriming_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) 
SOA:							stores the current SOA between onset of primes/noprimes
quadrant:						determines the screen quadrant in which the prime will appear

response:						the participant's response
correct:						the correctness of the response (1 = correct; 0 = incorrect)
latency: 						the response latency (in ms)
totalcorrect:					keeps a total of the correct responses

(2) Summary data file: 'ParafovealPriming_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)
totalcorrect:					keeps a total of the correct responses

(1) 6 Practice Trials
(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)	

(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. 
		It is therefore important to determine the correct screen size for each computer this script runs on 
		(either fill in the correct info during runtime or change parameters.screenheight under EDITABLE VALUES)
	(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 cm 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 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 
		(!you need to set parameters.screenheight to do so)


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:			the diagonal distance of the prime from the fixation (measured in cm)
screenheight:						can be directly edited here, or will be asked on runtime (measured in cm)
fontheight_incm:					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

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