Attention
Choice Reaction Time Task
Capture decision speed and response selection cost with a simple two-choice attention paradigm.
3-4 minTimed: desktop or laptop with a mouse or trackpad
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Try it here first, with no account.
- Papers, 2021 to 2025
- 478
- Evidence grade
- A
- Registered clinical studies
- 270
Example data
One session, scored by the code that scores your study's sessions.
Mean Reaction Time
458.6ms
Average RT on correct trials only.
Quality check: valid40 scored trials
- Median Reaction Time
- 446 ms
- RT Standard Deviation
- 78.4 ms
- Accuracy
- 97.5%
- Correct Trials
- 39
- Error Trials
- 1
- Trials
- Mean
- Wrong answer
Trial file
The first 6 of 48 rows, with the column names of your study's export.
| participant_id | test_slug | test_version | scoring_version | trial_index | trial_type | response | rt | correct | time_elapsed | correct_response | plugin_version | position | run_id | task |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| simulated | crt | 1.0.0 | 1.0.0 | 0 | html-keyboard-response | ArrowLeft | 352 | true | 3252 | ArrowLeft | 2.1.0 | left | example-run | crt_practice |
| simulated | crt | 1.0.0 | 1.0.0 | 1 | html-keyboard-response | ArrowRight | 474 | true | 4226 | ArrowRight | 2.1.0 | right | example-run | crt_practice |
| simulated | crt | 1.0.0 | 1.0.0 | 2 | html-keyboard-response | ArrowRight | 382 | true | 5108 | ArrowRight | 2.1.0 | right | example-run | crt_practice |
| simulated | crt | 1.0.0 | 1.0.0 | 3 | html-keyboard-response | ArrowRight | 656 | true | 6264 | ArrowRight | 2.1.0 | right | example-run | crt_practice |
| simulated | crt | 1.0.0 | 1.0.0 | 4 | html-keyboard-response | ArrowLeft | 293 | true | 7057 | ArrowLeft | 2.1.0 | left | example-run | crt_practice |
| simulated | crt | 1.0.0 | 1.0.0 | 5 | html-keyboard-response | ArrowLeft | 579 | true | 8136 | ArrowLeft | 2.1.0 | left | example-run | crt_practice |
What it measures
Measures attention and decision speed by requiring participants to select the correct response based on which stimulus appears.
Constructs
- Selective attention
- Decision speed
- Stimulus-response mapping
- Perceptual discrimination
Research uses
- Attention deficit screening
- Decision-speed assessment in aging
- Concussion sideline testing
- Pharmacological trial endpoints
How the paradigm works
The Choice Reaction Time task extends simple reaction time by adding a decision component. A stimulus (colored circle) appears on either the left or right side of the screen, and participants must press the corresponding arrow key. This stimulus-response mapping requires both stimulus identification and response selection.
More about the paradigm
The difference between CRT and SRT isolates the time required for decision-making, a relationship formalized by Hick's Law (1952): reaction time increases logarithmically with the number of stimulus-response alternatives.
A fixation cross maintains central gaze between trials. The task measures the speed and accuracy of basic perceptual decision-making under minimal cognitive load, serving as an intermediate measure between pure processing speed (SRT) and tasks requiring inhibition or conflict resolution.
Scores
- Mean Reaction Timems
- Average RT on correct trials only. Primary measure of decision speed.
- Lower is better
- Median Reaction Timems
- Median RT on correct trials, robust to outliers.
- Lower is better
- RT Standard Deviationms
- Variability in reaction times across correct trials.
- Lower is better
- Accuracy%
- Proportion of correct responses (correct key pressed).
- Higher is better
- Correct Trialscount
- Number of trials with a correct response.
- Higher is better
- Error Trialscount
- Number of trials with an incorrect key press.
- Lower is better
Use and evidence
478 papers from 2021 to 2025 name this task in their title or abstract, down 12% compared with 2016 to 2020. That ranks it 57 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 111 |
| 2024 | 93 |
| 2023 | 81 |
| 2022 | 85 |
| 2021 | 108 |
| 2020 | 94 |
| 2019 | 146 |
| 2018 | 90 |
| 2017 | 121 |
| 2016 | 93 |
| 2015 | 115 |
| 2014 | 118 |
| 2013 | 120 |
| 2012 | 128 |
| 2011 | 112 |
| 2010 | 95 |
| 2009 | 95 |
| 2008 | 71 |
| 2007 | 83 |
| 2006 | 97 |
| 2005 | 85 |
| 2004 | 81 |
| 2003 | 82 |
| 2002 | 82 |
| 2001 | 76 |
| 2000 | 74 |
Use grade B
300 to 999 papers from 2021 to 2025.
Evidence grade A
At least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome.
- Papers on test-retest reliability
- 31
- Papers on reliability or validity
- 274
- Registered clinical studies using it as an outcome
- 270
Measured on ConductCognition
Pooled across the studies that feed our platform norms, by device group. A figure needs 50 or more people.
No pooled figure yet.
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: crt_test, two keys (chance 50%). Below chance invalidates and not above chance is flagged. One key on 90% of answers invalidates when accuracy is not above chance. No response window, so nothing can be missed; responses under 100 ms follow the timed-test rule.
Why these rules
Accuracy significantly below chance (one-sided exact test, p < .05) cannot come from guessing; it means the response mapping was reversed or the task was not followed (Slick, Sherman and Iverson 1999 treat below-chance forced-choice performance as definite response bias). Chance-level accuracy can be a real result in impaired participants, so it is only flagged. One option on at least 90% of answered trials, when the correct options are balanced and accuracy is not above chance, means the answers did not depend on the items (the task counterpart of long-string responding in surveys; Curran 2016). Missed responses and responses under 100 ms keep the platform's timed-test rule: more than max(3, 25%) missed responses or more than max(2, 20%) responses under 100 ms invalidate, and any is flagged. A response under 100 ms cannot be a reaction to the stimulus.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Number of trials | 40 | 20 to 80 |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Timed test: participants need a desktop or laptop with a mouse or trackpad. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Included in these batteries
Each battery runs this test with others in a fixed order, with standard settings.
- Reaction Time Study2 tests, 7 minutes per participant
- Pilot Screening Battery4 tests, 15 minutes per participant
- Language-Minimized Screening Battery8 tests, 30 minutes per participant
- Medication Studies Battery5 tests, 26 minutes per participant
Cite and describe
Participants completed the Choice Reaction Time task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Donders, 1869; Hick, 1952), with the standard settings (number of trials: 40). The main score was mean reaction time (average RT on correct trials only).
Participants will complete the Choice Reaction Time test online through ConductCognition, a browser-based cognitive testing platform from ConductScience. The test will take about 3 to 4 minutes. The test is timed. Timed tests need a desktop or laptop with a mouse or trackpad. A device check runs before the first test and stops a device the protocol cannot run on. ConductCognition runs in the participant's web browser. Nothing is installed.
Paradigm source: Donders (1869); Hick (1952).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
Source papers
- Woods DL, Wyma JM, Yund EW, Herron TJ, Reed B (2015). Age-related slowing of response selection and production in a visual choice reaction time task. Frontiers in Human Neuroscience, 9:193.Paradigm source
Questions
How long does the Choice Reaction Time Task take?
About 3 to 4 minutes, as listed in the test library.
What device does a participant need?
Timed test: participants need a desktop or laptop with a mouse or trackpad. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Mean Reaction Time, Median Reaction Time, RT Standard Deviation, Accuracy, Correct Trials and Error Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Choice Reaction Time Task used in research?
478 papers from 2021 to 2025 name it in their title or abstract, down 12% compared with 2016 to 2020. That ranks it 57 of 582 test families in the ConductCognition test census (use grade B). Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Choice Reaction Time Task have?
In the published research, 31 papers report its test-retest reliability and 270 registered clinical studies use it as an outcome (evidence grade A in the ConductCognition test census).
Which settings can a researcher change?
Number of trials (20 to 80). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
Run this test in your next study
Start free with 10 free participants on any test, then use participant credits or a yearly plan.