Detection Task

Technical Manual

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

Created: April 26, 2022

Last Modified: September 02, 2026 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a simple reaction time task inspired by the 'Detection Task' of the CogState Brief Battery described by Maruff et al (2009). The DET is a computerized measure of psychomotor function and information processing speed. The task uses playing cards as targets and is developed for touchscreens but the Inquisit implementation will adapt to mouse use on non-touchscreens.

Note: the Inquisit script runs with proportional sizing by default. Researchers can select to run the task with an absolute screen size to ensure that distances stay the same across devices. See section Defaults for more info.

References

Maruff P, Thomas E, Cysique L, Brew B, Collie A, Snyder P, Pietrzak RH. Validity of the CogState brief battery: relationship to standardized tests and sensitivity to cognitive impairment in mild traumatic brain injury, schizophrenia, and AIDS dementia complex. Arch Clin Neuropsychol. 2009 Mar;24(2):165-78. doi: 10.1093/arclin/acp010. Epub 2009 Mar 25. PMID: 19395350.

Duration

3 minutes

Description

Participants get presented with a deck of joker cards and the cards will be turned over one by one with randomly selected delays. Once a joker card is turned over, participants are instructed to press a YES response button as quickly as possible. Once the response is made, an animation is started that 'returns' the card back to the stack. The next trial is initiated once participants press a 'Home Button'. The 'Home Button' is implemented to ensure that response fingers are roughly equally distanced from the YES response button for each trial.

Procedure

Test:
by default this script runs 1 testblock (Editable Parameter) with 35 trials each (Editable Parameter)
using the same joker card for every trial. The script provides a brief resttrial (self-paced) after each block.
The script randomly samples a joker delay from 500-5000ms (Editable Parameter)

Trial Information:
-> each trial starts with a HomeButton press (reminder presented after 2s)
-> pressing the home button starts the delay period
(if the home button is released during this time for more than 250ms, participants
are asked to return to the home button and a new iti is randomly selected)
-> after the delay period is over, the joker card is turned over,
and the script waits for response (there is no time limit for making a response)
-> card animation for 1000ms
(if the home button is pressed at the end of the card animation, the next trial starts immediately
with the delay period)

Stimuli

see section Editable Stimuli

Instructions

provided by Millisecond - can be edited under section Editable Instructions
in script 'detectiontask_instructions_inc.iqjs'

Summary Data

File Name: detectiontask_raw*.iqdat

Data Fields

NameDescription
startDate Date the session was run
startTime Time the session was run
subjectId Participant ID
groupId Group number
sessionId Session number
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
elapsedTime Session duration in ms
completed 0 = Test was not completed
1 = Test was completed
distanceHomeButtonResponseButtonMM The calculated distance (in mm) between center of homeButton and center of one of the response buttons
Parameter Settings
blocksPerTest Number of test blocks run
trialsPerBlock Number of trials per block to run
Accuracy
trialCounter Number of test trials run
prCounter Number of premature lift-offs (results in trial repeat)
nrCounter Number of no responses (response is timed out, counted as error response)
propCorrect Proportion of yes-responses relative to trialCount
Reaction Time Performance Metrics (Response Time Measured Relative To Target Onset; Excludes No Responses)
meanRT Mean response time (in ms)
sdRT Standard deviation of response times (in ms)
meanRTLog10 Log10 transformed mean response time
sdRTLog10 Log10 transformed sd of response times
medianRT Median response time (in ms)
minRT Minimum response time (in ms)
maxRT Maximum response time (in ms)
Delay Performance Metrics
meanDelay Mean delay time (in ms)
sdDelay Standard deviation of delay times (in ms)
medianDelay Median delay time (in ms)
minDelay Minimum delay time (in ms)
maxDelay Maximum delay time (in ms)

Raw Data

File Name: detectiontask_raw*.iqdat

Data Fields

NameDescription
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
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
distanceHomeButtonResponseButtonMM The calculated distance (in mm) between center of homeButton and center of one of the response buttons
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.
blockCounter The total number of experimental blocks run
trialCounter Counts the target and nontarget trials per block ( start trials are excluded from count)
Dvs
response The Response of the participant
correct The correctness of the response (1 = correct; 0 = otherwise)
latency How fast a participant responded within the given timeframe, if at all (in ms)
no responses = the entire trialduration

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
Design Parameters
blocksPerTest Number of blocks per test1
trialsPerBlock Number of n-back trials per block (excluding starttrials)35
Color Parameter
canvasColor Display color of the actively used portion of the screen (the 'canvas')
if set to a color other than the screenColor, you can distinguish the active canvas
from the inactive portion of the screen
black
screenColor Color of the screen not used by the canvas ('inactive screen')black
defaultTextColor Default color of text itemswhite
Sizing Parameters
cardSizePct The height of the cards in canvas height percentage40%
Timing Parameters
minDelayMs The minimum delay (in ms) with which the joker can be be uncovered500
maxDelayMs The maximum delay (in ms) with which the joker can be be uncovered5000
homeButtonBufferDurationMs The max. time (in ms) that participants can stray from the home button
before joker appears (otherwise trial gets repeated)
250
maxResponseTimeoutMs The maximum time (in ms) that test waits for a response before timing out2000