Long Rosvold Continuous Performance Task - CPT

Technical Manual

Millisecond thanks Ilana Hairston (hanahai@telhai.ac.il) for sharing the Hebrew translations!
Note from Ilana Hairston:
This script was adapted to be used in Hebrew. Some of the instructions are hidden due to problems with
display of Hebrew fonts. If you want to edit the text, copy and paste the element into any simple text editor,
make the changes and then paste back into Inquisit.
GOOD LUCK!

Last Modified: February 19, 2026 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements the Continuous Performance Test, a test of sustained and selective attention. This script implements the long version of the task (adult version).

References

Rosvold, H.E., Mirsky, A., Sarason, M., Bransome, E.D., Jr., and Beck, L.H. A Continuous Performance Test of brain damage. Journal of Consulting Psychology, 20, 343 (1956).

Duration

25 minutes

Description

Participants get presented a sequence of letters (one-by-one). Task1: press the Spacebar whenever the letter is an X Task2: press the Spacebar whenever the letter is an X that follows an A.

Procedure

(1) phase "X":
- 2 blocks practice
- 20 (long version) test blocks (duration of test blocks: ~ ~10 min total for long version)
- each blocks runs 31 letters with 8 targets (order is randomly determined)
- the no-target letters are selected randomly WITH replacement from item.xLetters

(2) phase "AX"
- 2 blocks practice
- 20 (long version) test blocks
- each block runs 31 letters with: 6 targets (target = letter X that follows an A) ~10 min total for long version)
- the no-target letters are selected randomly WITH replacement from item.axLetters (with the constraint that no A is followed by an X)
in this script, any letter can precede an X (including X itself); any letter can follow an A (including A itself);
the number of 'no-signal As' as well as 'no target Xs' are randomly determined per block

Trial Sequence:
letter (690ms)-> ISI: blank screen (230ms)-> letter....
response is accepted until end of letter duration
(trial timings can be edited under section Editable Parameters)

Instructions

see section Editable Instructions

Summary Data

File Name: cpt_rosvold_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
blockCountXPractice Counts the number of practice blocks run for phase X
blockCountXTest Counts the number of test blocks run for phase X
blockCountAxPractice Counts the number of practice blocks run for phase AX
blockCountAxTest Counts the number of test blocks run for phase AX
xTestSignalTrialCount Counts all signal (=target) trials during Phase X
xTestMissCount Number of errors when X was presented but no response was given during Phase X
xTestMissRate Omission rate during Phase X
xTestHitRate Hit rate during Phase X
xTestNoiseTrialCount Counts all non-signal (= non target) trials during Phase X
xTestFalseAlarmCount Number of false alarms during Phase X
xTestFalseAlarmRate Commission rate during Phase X
xTestCorrRejectRate Correct rejection rate during Phase X
Signal Detection Measures
zHitRatextest The calculate z-score of the hitRate during Phase X
zFARaTextest The calculated z-score of the falseAlarm/commission rate during Phase X
*Adjustments to z-scores as recommended by
Gregg, A. & Sedikides, C. (2010). Narcissistic Fragility
Rethinking Its Links to Explicit and Implicit Self-esteem, Self and Identity, 9:2, 142-161 (p.148)
=> Adjustments are made if the FArate (hitRate) = 0 (increased to 0.005) or 1 (decreased to 0.995)*
dPrimeXTest Computes d' (parametric measure of discriminability btw. signals and noise)
=> Range (in this script)
-5.1516586840152740479 <= dprime <= 5.1516586840152740479 (=perfect performance)
=> The higher the value, the better signals (go stims) were overall distinguished from noise (nogo stims)
(d' = 0: chance performance; negative d-primes: participant treated nontargets as targets and targets as nontargets)
cXTest C-criterion in signal detection:The absolute value of c provides an indication of the strength of
the response bias/response style
negative: participant more likely to report that signal is present (liberal response style)
may favor faster responding in speed-accuracy trade-off response paradigms
positive: favoring caution (conservative response style)
axTestSignalTrialCount Counts all signal (=target) trials during Phase AX
axTestMissCount Number of errors when X was presented but no response was given during Phase AX
axTestMissRate Omission rate during Phase AX
axTestHitRate Hit rate during Phase AX
axTestNoiseTrialCount Counts all non-signal (= non target) trials during Phase AX
axTestFalseAlarmCount Number of false alarms during Phase AX
axTestFalseAlarmRate Commission rate during Phase AX
axTestCorrRejectRate Correct rejection rate during Phase AX
Signal Detection Measures
zHitRateAXTest The calculate z-score of the hitRate during Phase AX
zFARateAXTest The calculated z-score of the falseAlarm/commission rate during Phase AX
dPrimeAXTest D' for Phase AX
cAXTest Calculated c-criterion for Phase AX

Raw Data

File Name: cpt_rosvold_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
phase Current phase of the procedure: "x practice" vs. "x test", "ax practice" vs. "ax test"
blockCountXPractice Counts the number of practice blocks run for phase X
blockCountXTest Counts the number of test blocks run for phase X
blockCountAxPractice Counts the number of practice blocks run for phase AX
blockCountAxTest Counts the number of test blocks run for phase AX
previousLetter The letter presented in the previous trial
currentLetter The letter presented in the current trial
response The scancode for the key that was pressed (if any)
57 = spacebar press
0 = noResponse
correct Whether the response was correct: 1 = correct; 0 = error
latency The response time in milliseconds; measured from onset of letter

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
restTime The time of the rest duration in ms 120000ms => 2 min
letterDuration Duration of the letters in ms (time to respond)690ms
isi Interstimulus interval (= blank screen) in ms 230ms
letterHeight The size (proportional to canvas height) of the the letters 8%