Simple Auditory Reaction Time Task

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Last Modified: January 11, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script runs a simple auditory reaction time task.

Duration

2 minutes

Description

After variable time intervals, a sound is played to the participant. The task is to press the spacebar as soon as the sound is presented. Mean and Median latency, latency standard deviation as well as minimum latency and maximum latency are recorded in the summary data file.

Procedure

• By default, the script runs 1 block of 20 trials
• the time intervals are randomly chosen from 2000ms, 3000ms, 4000ms, 5000ms, 6000ms, 7000ms, 8000ms intervals
• By default, the sound is panned through both speakers.
• By default, the sound volume is not adjusted.
• By default, the color of the screen background is white.

Stimuli

see section Editable Stimuli

Instructions

Instructions are provided by Millisecond
as htm/html pages and can be edited by changing the provided htm/html files.
To edit htm/html-files: open the respective documents in simple Text Editors such as TextEdit (Mac)
or Notepad (Windows).

Summary Data

File Name: srtauditory_summary*.iqdat

Data Fields

NameDescription
inquisit.version Inquisit version number
computer.platform Device platform: win | mac |ios | android
computer.touch 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities
computer.hasKeyboard 0 = no external keyboard detected; 1 = external keyboard detected
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
targetspeaker The current speaker through which target is presented
volumeadjust The current volume adjustment
speakerfixed Determines whether to play the sound though a fixed speaker or randomly through either the left, the right, or both speakers.
maxtrialnumber The number of valid trials in a block that should be run
meanRT The mean response times (in ms) of valid responses (first trial excluded)
sdRT The standard deviation (in ms) of the response times of valid responses (first trial excluded)
medianRT The median response times (in ms) of valid responses (first trial excluded)
minRT The fastest response time (in ms) of valid responses (first trial excluded)
maxRT The slowest response time (in ms) of valid responses (first trial excluded)
countEarlyResponses Counts the number of times the spacebar was pressed before the sound was played (excludes first trial)

Raw Data

File Name: srtauditory_raw*.iqdat

Data Fields

NameDescription
build Inquisit version number
computer.platform Device platform: win | mac |ios | android
computer.touch 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities
computer.hasKeyboard 0 = no external keyboard detected; 1 = external keyboard detected
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
blockcode The name the current block (built-in Inquisit variable)
blocknum The number of the current block (built-in Inquisit variable)
trialcode The name of the currently recorded trial (built-in Inquisit variable)
trialnum The number of the currently recorded trial (built-in Inquisit variable)
trialnum is a built-in Inquisit variable; it counts all trials run
even those that do not store data to the data file.
targetspeaker The current speaker through which target is presented
volumeadjust The current volume adjustment
speakerfixed Determines whether to play the sound though a fixed speaker or randomly through either the left, the right, or both speakers.
maxtrialnumber The number of valid trials in a block that should be run
stimDelay The current delay (in ms) of the sound
stimulusItem The presented stim (here the sound file)
response The participant's response (scancode of response buttons)
57 = spacebar
correct Accuracy of response
1 = correct response (response was made after sound was played)
0 = otherwise (= early response)
latency The trial latency (in ms); measured from: onset of trial until response was made
rtStim The time btw. onset of sound until response was made (in ms)
countEarlyResponses Counts the number of times the spacebar was pressed before the sound was played (excludes first trial)
countValidTrials Counts the number of times the spacebar was pressed after the sound was played (excludes first trial)

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
Design
maxTrialNumber Sets the number of valid trials that should be run in a block
Notes
b) early response trials are not considered valid and are repeated
a) the first trial is considered 'practice' and does not count towards trialnumber)
20
Sound Details
targetSpeaker Sets the speaker through which the sound is presented
Alternatives: -10000 (only through the left speaker) 10000 (only through the right speaker)
0
volumeAdjust Sets a volume adjuster; -10000 sets it to silent, 0 makes no adjustments to the original sound0
speakerfixed Determines whether to play the sound though a fixed speaker or randomly through either
the left, the right, or both speakers.
0
volumefixed Determines whether to randomly adjust the volume of the sound or use a fixed volume
(0 = fixed volume; 1 = random volume adjustment); default is 0
0
Colors
screenColor Sets the background color of the screenwhite