Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 23, 2014
Last Modified: January 08, 2024 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script runs an auditory Stroop procedure.
The classic Stroop paradigm, using visual stimuli, demonstrates the interference of word meaning on naming the color in which the words are written as measured by reaction time/accuracy differences to color-meaning congruent and color-meaning incongruent combinations. This Auditory Stroop Procedure tests the interference effect using auditory congruent and incongruent stimuli combinations in three sound dimensions: pitch, loudness, duration.
Morgan, A.A.R. & Brandt, J.F. (1989). An Auditory Stroop Effect for Pitch, Loudness, and Time. BRAIN AND LANGUAGE 36, 592-603.
30 - 40 minutes
Participants hear Stroop and Non-Stroop words of 3 different acoustic dimensions (pitch, loudness, duration).
Stroop Words: words that are related to the acoustic dimension (e.g. pitch: low) Non-Stroop Words: words that are neutral in relation to the acoustic dimensions (e.g. cat)
Depending on the acoustic dimension tested, they have to make categorical judgments and sort the word into one of 2 categories as fast as possible. Example: they hear 'cat' in a low-pitched voice and are asked to either press the response key dedicated to 'low' or press the response key dedicated to 'high'.
6 acoustic dimensions (pitch/pitchcontrol, loudness/loudnesscontrol, duration/durationcontrol): tested within-subject, mixed design
!!! if the acoustic dimensions (pitch/loudness/duration) should be tested in a blocked-design, go to
section EXPERIMENT and follow instructions
3 levels per acoustic dimension (e.g. pitch: low, high, neutral): tested within-subject, mixed design
6 stimuli per acoustic dimension
3 repetitions per stimuli
Stimulus Onset Asynchrony: 5s => soundfiles are presented 5s apart (Editable Parameters)
=> 6 acoustic dimensions x 3 levels x 6 stimuli x 3 repetitions = 2 x 324 trials
Ear condition: parameters.earCondition (Editable Parameters) sets whether the stimuli are presented through one ear (left or right)
as done by Morgan & Brandt (1989) or both ears at the same time. By default, this script runs the dual channels conditions.
Response key assignments to left or right: by default the left and right response keys are the 'A' and 'L' keys (change under Editable Parameters)
Assignment of low-high, soft-loud, short-long response keys to the left and right response key (2 possible orders) is counterbalanced
by odd vs. even groupnumber (See section EXPERIMENT for more info)
Blocks:
Training
(1) Stabilization: participants are asked to respond randomly with the left and right response keys to various beeps (20 trials, editable parameter)
(2) Familiarization: participants are presented all experimental stimuli but no response is required. The presentation
stream can be paused in this script and the last stimuli repeated.
!!! parameters.run_Stabilization/parameters.run_Familiarization (Editable values) control if these blocks are run.
If parameters.session_nr > 1, these values are automatically set to false (and these training blocks are skipped)
(3) Practice: participants are asked to respond to a block of 12 randomly selected experimental stimuli by pushing the response button that
corresponds to the instructions (e.g. LEFT/RIGHT) on the screen. LEFT/RIGHT instructions are randomly selected without replacement.
Participants have to hit a certain criterium to move from practice otherwise another block of 12 trials is started.
Criterium to quit practice:
If the standard deviation of the response latencies of those 12 trials < 50% of the mean latency of those 12 trials (Morgan & Brandt, 1989, p.597)
Practice is stopped after max 3 runs (see setting of parameters.maxPracticeBlocks) and the test is started.
it is noted in the datafiles whether participants have reached the practice stop criterium.
Experimental Block:
(4) 324 trials: runs all 54 possible trials of each acoustic dimension (6 acoustic dimensions)
(54 => 3 levels x 6 stimuli per level x 3 repetitions per stimuli)
! the semi-random order of the 324 trials is generated before each session by
included helper script 'stimordergeneration.iqjs' with the following constraints:
the same dimension (pitch, loudness, duration, control) cannot be run consecutively
(this includes not running a pitched control word after a pitched stroop word etc.)
The provided sound files are not original to Morgan & Brandt (1989). They are provided by Millisecond.
All recordings by a male native speaker of American English.
Pitch & Duration were manipulated in Audacity.
Volume is manipulated by script itself
(neutral volume is set to be at -1000 for all conditions; loud is set to be at 0; and soft is set to be at -2000 - editable values)
Stimuli can be exchanged under section Editable Stimuli
The provided instructions are not original to Morgan & Brandt (1989). They are provided by Millisecond.
The instructions are presented in the form of html pages. To change the instructions, edit the corresponding
html files.
To edit htm/html-files: open the respective documents in simple Text Editors such as TextEdit (Mac)
or Notepad (Windows).
File Name: auditorystroop_acousticdimensions_summary*.iqdat
| Name | Description |
|---|---|
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| startDate | Date the session was run |
| startTime | Time the session was run |
| subjectId | Participant ID |
| groupId | Group number |
| sessionId | Session number |
| elapsedTime | Session duration in ms |
| completed | 0 = Test was not completed 1 = Test was completed |
| earCondition | 1 = right ear is tested 2 = left ear is tested 3 = dual channels |
| practiceCounter | Tracks the number of practice blocks run (MAX = parameters.maxPracticeBlocks) |
| practicePass | 0 = practice pass condition has not been reached (yet) 1 = practice pass condition has been reached |
| propcorrCP | Proportion correct congruent pitch trials |
| propcorrICP | Proportion correct incongruent pitch trials |
| meanRTCP | Mean RT (in ms) of correct congruent pitch trials |
| meanRTICP | Mean RT (in ms) of correct incongruent pitch trials |
| meanRTNP | Mean RT (in ms) of neutral pitch trials (same for loudness 'L' and duration 'D' ) |
| propcorrCompCtrlP | Proportion correct comparison control pitch trials (comparison to congruent and incongruent trials) |
| meanrtCompCtrlP | Mean RT (in ms) of correct comparison control pitch trials ! comparison control trials = level 1 and level 2 (excluding the neutral stimuli) |
| meanrtNCtrlP | Mean RT (in ms) of neutral (level3) control pitch trials (same for control loudness 'ctrlL' and control duration 'ctrlD' ) |
File Name: auditorystroop_acousticdimensions_raw*.iqdat
| Name | Description |
|---|---|
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockCode | Name of the current block |
| blockNum | Number of the current block |
| trialCode | Name of the current trial |
| trialNum | Number of the current trial |
| earCondition | 1 = right ear is tested 2 = left ear is tested 3 = dual channels |
| dimension | 1 = pitch 2 = loudness 3 = duration 4 = control_pitch 5 = control_loudness 6 = control_duration |
| level | 1 = high/loud/long 2 = low/SOFT/short 3 = neutral |
| congruence | 0 = neutral/control 1 = congruent 2 = incongruent |
| volume | Stores the current word volume |
| selectedItemNumber | Stores the actual itemnumber of the current stimulus (e.g. item 5 of level HIGH -> itemnumber: 11 of item.pitchwords) |
| practiceInstruct | Either Right (1) or Left (2) ear instructions for practice trials for a practice trial |
| stimulusItem | The presented stimuli in order of trial presentation |
| response | The participant's response (scancode of response key) 30 = A 38 = L |
| responseCategory | The interpreted key response: "high" vs. "low", "loud" vs. "SOFT", "long" vs. "short" |
| correct | The correctness of the response (1 = correct; 0 = incorrect) by design accuracy of response of "neutral stimuli" (level3 stimuli) is always set to 1 in this script |
| latency | The response latency (in ms); measured from onset of word |
| block.practice.meanLatency | Stores the calculated mean response latency of the current practice block trial-by-trial |
| block.practice.sdLatency | Stores the calculated standard deviation of the response latencies of the current practice block trial-by-trial |
| practiceCounter | Tracks the number of practice blocks run (MAX = parameters.maxPracticeBlocks) |
| practicePass | 0 = practice pass condition has not been reached (yet) 1 = practice pass condition has been reached |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Design Parameters |
||
| earCondition | 1 = right ear is tested; 2 = left ear is tested; 3 = dual channels (default) | 3 |
| runStabilization | True: runs the stabilization procedure false: does not run the stabilization procedure => might have to update default instructions | true |
| stabilizationTrials | Number of stabilization trials to run => Max number that can be run is 108 | 20 |
| runFamiliarization | True: runs the familiarization procedure false: does not run the familiarization procedure => might have to update default instructions if parameters.session_nr = 2; parameters.run_Stabilization and parameters.run_Familiarization are set to fault automatically | true |
| maxPracticeBlocks | Max number of practice blocks before test is started | 3 |
Duration Parameters |
||
| familiarizationDuration | Duration (in ms) of the stimuli presentations during familiarization trials | 2000 |
| soa | Stimulus onset asynchrony: time between onset of one stimulus and the onset of the next in ms (default: 5000) -> every 5 s a new word is spoken. | 5000 |
Volume Adjustment |
||
| loudVolume | Volume setting for the loud volume a setting of 0 plays the sound file at the recorded volume (0 is the max setting) | 0 |
| neutralVolume | Volume setting for all neutral sound files a slight volume reduction | -1000 |
| softVolume | Volume setting for all soft sound files | -2000 |
Responsekeys |
||
| responseKeyLeft | "A" | |
| responseKeyRight | "L" | |