Perceptual Vigilance Task - Keyboard

Technical Manual

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

Last Modified: January 12, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script runs a simple visual reaction time task similar to the one described by:

Wilkinson, R. T., & Houghton, D. (1982). Field test of arousal: A portable reaction timer with data storage. Human Factors, 24, 487-493.

Duration

10 minutes

Description

Participant are asked to press the SPACEBAR as soon as they see a red circle appearing on screen. Afterwards, their reaction is displayed for 0.5s (editable). The test is timed and stops after 10min (editable). Mean and Median latency, latency standard deviation as well as minimum latency and maximum latency are recorded in the summary data file.

Procedure

(a) By default, the target stimulus appears in the center of the screen. Changes can be made under
"Editable Parameters", including changing the script so that the target stimuli appear randomly in one of 9 screen positions.

(b) By default, the time intervals are randomly chosen (with replacement) from 1000ms, 2000ms, 3000ms, 4000ms, 5000ms, 6000ms, 7000ms, 8000ms, 9000ms, 10000ms
Changes can easily be made under "Editable Lists"

(c) By default, the test runs for 10 Minutes. Changes can be made under "Editable Parameters -> parameters.testduration"

(d) By default, the color of the circle is red. Changes can be made under "Editable Parameters"

Procedure:
Task starts with the presentation of a red circle (this response latency not considered for summary statistics).
Immediately after the left or right mouse button response, the next trial starts randomly selecting one of the
10 possible stimintervals.
If a response is made prior to the appearance of the red circle, the trial terminates and a new trial starts.
The number of early responses are counted.

Instructions

The instructions can be easily changed under "Editable Instructions"
in script "perceptualvigilancetest_keyboard_instructions_inc.iqjs"

Summary Data

File Name: perceptualvigilancetask_keyboard_summary*.iqdat

Data Fields

NameDescription
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
parameters- testduration Duration of test: recommended minimum time is 600000ms => 10 min
parameters- targetcolor The current color of the target circle
parameters- targetsize The current color of the target circle
parameters- fixed 1= fixed position of target; 0 = random position of target
parameters- targetx The x-coordinate of the target circle
parameters- targety The y-coordinate of the target circle
countEarlyResponses Count of all early responses
countResponses Running count of the number of responses made
(includes early responses but excludes the first response made)
proportionEarlyResponses Proportion early responses (in relation to total number of responses made)
latency data is based on valid responses only (excludes early responding)
meanRT Mean response latency in ms (for trials that were responded to)
std Standard deviation of the response latencies (for trials that were responded to)
medianRT Median latency in ms (for trials that were responded to)
minRT Minimum response latency (in ms)
maxRT Maximum response latency (in ms)

Raw Data

File Name: perceptualvigilancetask_keyboard_raw*.iqdat

Data Fields

NameDescription
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
parameters- testduration Duration of test: recommended minimum time is 600000ms => 10 min
parameters- targetcolor The current color of the target circle
parameters- targetsize The current color of the target circle
parameters- fixed 1= fixed position of target; 0 = random position of target
parameters- targetx The x-coordinate of the target circle
parameters- targety The y-coordinate of the target circle
stimInterval Determines how long the focus stimulus is shown before the target stimulus is presented
trialStart Script.elapsedTime (in ms) at start of trial (script.elapsedTime measured from start of script)
response The scancode of the key pressed (here: 57 = spacebar)
latency Response time (in ms); measured from start of trial (NOT CIRCLE)
shape.targetCircle.stimulusOnset: the trial timestamp of the presented target circle
rt Stores the current response latency (in ms)
calculated as the difference of (latency - shape.targetcircle.stimulusOnset)
if response was made BEFORE onset of circle Latency = "early response"
earlyResponse 1 = the response was given before the circle appeared
0 = the response was given after the circle appeared
countEarlyResponses Count of all early responses
countResponses Running count of the number of responses made
(includes early responses but excludes the first response made)

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
targetColor Sets the color of the circle; the default is red
targetSize Sets the size of the circle; the default is 10% of the vertical screen
targetx Sets the x-coordinate of the target circle ; the default is the center (50%)
targety Sets the y-coordinate of the target circle , the default is the center (50%)
feedbackHeight Height of feedback text stimulus (relative to canvas height) 5%
fixed Determines whether to use the fixed coordinates for the target stimulus (= 1)
or to select randomly from 9 different screen positions (= 0)
default is 1 (= fixed position)
testDuration Duration of test: recommended minimum time is 600000ms => 10 min
presentTrialFeedback True = after each trial the response latency is reported (default)
false = no trial response latencies are reported
rtFeedbackDuration Duration of feedback
feedback duration is counted towards taskduration
500ms