___________________________________________________________________________________________________________________ *SUBLIMINAL PRIMING PROCEDURE* ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC Date: 04-25-2013 last updated: 03-01-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC Script Copyright © 03-01-2022 Millisecond Software ___________________________________________________________________________________________________________________ BACKGROUND INFO ___________________________________________________________________________________________________________________ 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. ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ 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). ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ the default set-up of the script takes appr. 3 minutes to complete ___________________________________________________________________________________________________________________ DATA FILE INFORMATION ___________________________________________________________________________________________________________________ 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) 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. prime1: stores the assigned prime1 item prime2: stores the assigned prime2 item selectprime1/ store the assignment (itemnumber) of primes to prime1 and prime2 selectprime2: 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) 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) display.refreshrate: refreshrate of monitor propcorrect: overall proportion correct (test trials only) meanRT: overall correct mean latency in ms (test trials only) //see prime1 & prime2 for which prime was assigned prime1 and prime2 prime1: stores the assigned prime1 item prime2: stores the assigned prime2 item propcorrect_prime1pos: proportion correct in Prime1-Positive Adjective Pairings propcorrect_prime1neg: proportion correct in Prime1-Negative Adjective Pairings propcorrect_prime2pos: proportion correct in Prime2-Positive Adjective Pairings propcorrect_prime2neg: proportion correct in Prime2-Negative Adjective Pairings meanrt_prime1pos: correct mean latency (in ms) in Prime1-Positive Adjective Pairings meanrt_prime1neg: correct mean latency (in ms) in Prime1-Negative Adjective Pairings meanrt_prime2pos: correct mean latency (in ms) in Prime2-Positive Adjective Pairings meanrt_prime2neg: correct mean latency (in ms) in Prime2-Negative Adjective Pairings ___________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ * 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 ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ most of the stimuli used in this script are not the originals; they can be edited under section Editable Stimuli ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ the instructions used in this script are not originals; they can be edited under section Editable Instructions ___________________________________________________________________________________________________________________ EDITABLE CODE ___________________________________________________________________________________________________________________ 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")