Response Inhibition
Anticipatory Inhibition Task
Also called: anticipated response inhibition task, anticipatory response inhibition task, stop-signal anticipation task, Slater-Hammel task
Measure how well people stop a planned action as participants stop a rising bar on a line, and hold back when it stops by itself.
11-13 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
- 15
- Evidence grade
- D
- Registered clinical studies
- 0
What it measures
Measures how well people stop a planned action. A bar rises toward a line, and participants press the space bar to stop it on the line; on some trials the bar stops by itself before the line, and they must hold back. The main score is the stop-signal reaction time.
Constructs
- Response inhibition
- Action cancellation
- Anticipatory timing
- Inhibitory control
Research uses
- Response inhibition research
- Motor control research
- Developmental and aging research
- Within-study group comparison
How the paradigm works
The Anticipatory Inhibition Task measures how well a person stops a planned action. It is the anticipated response inhibition paradigm (Slater-Hammel, 1960) in the rising-bar form of Zandbelt and Vink (2010) and OSARI (He and colleagues, 2022). On each trial an empty bar waits for 1,000 ms, then fills from the bottom at a constant speed, meeting a line four fifths of the way up at 800 ms and reaching the top at 1,000 ms. The participant presses the space bar to stop the bar as close to the line as possible. On a quarter of the trials the bar stops by itself before the line, and the participant must hold back the press until the bar would have filled. After each trial a line under the bar says how far from the line the bar stopped, or whether the press was held back, as OSARI's colored target does.
More about the paradigm
The stop time follows the stop-signal test's rule, a one-up one-down staircase: after a stop trial held back the next bar stops 25 ms later, after a press 25 ms earlier. It starts at 500 ms and stays between 50 and 775 ms, OSARI's values; the start and the step are settings. The staircase converges on holding back about half the stop trials. The standard session is 10 practice trials, then 5 blocks of 30 go and 10 stop trials in an order drawn from the session's seed, with a rest between blocks: 50 stop trials, the minimum the consensus guide recommends (Verbruggen and colleagues, 2019). Because the line fixes when a go press should come, waiting for the stop does not help, the advantage He and colleagues give for this design over choice-reaction stop-signal tasks.
Scores
- Stop-Signal Reaction Timems
- Integration method with replacement of go omissions: the go press time at the rank of the share of stop trials pressed, minus the mean stop time.
- Lower is quicker stopping
- Stopping Errorms
- Mean distance in time between a go press and the line, over go presses at or after 100 ms.
- Lower is closer to the line
- Stop Trials Held Back%
- Share of stop trials with no press.
- Near 0.5 when the staircase has worked
- Signed Stopping Errorms
- Mean of go press time minus 800 ms, over go presses at or after 100 ms.
- Negative means before the line
- Go Press Timems
- Mean time from the bar's start to a go press, over presses at or after 100 ms.
- The line is at 800 ms
- Go Press Variabilityms
- Standard deviation of the go press times.
- Lower is steadier timing
- Failed-Stop Press Timems
- Mean press time on stop trials that were not held back.
- Earlier than go presses when the race model holds
- Mean Stop Timems
- Mean time from the bar's start to the frame that stopped it on stop trials.
- Informational
- SSRT Checks Passedflag
- 1 when the share of stop trials pressed is 0.25 to 0.75, at least 80% of go trials have a press, failed-stop presses come earlier than go presses, and there are at least 20 go presses and 16 stop trials.
- 0 withholds the percentile
- Go Trials Missedcount
- Go trials with no press before the bar filled.
- More than max(3, 25%) makes the session invalid
- Anticipationscount
- Go presses less than 100 ms after the bar started rising.
- More than max(2, 20%) makes the session invalid
- Presses Before the Bar Rosecount
- Presses while the bar waited, which stop nothing.
- Informational
- Frame Intervalms
- Median time between the display's frames while bars rose.
- Set by the display
- Dropped Frames%
- Frames the browser dropped while bars rose, of the frames due.
- Above 0.05 is flagged and withholds the percentile
- Go Trialscount
- Go trials in the scored run.
- Informational
- Stop Trialscount
- Stop trials in the scored run.
- Informational
- Stop Trials Pressedcount
- Stop trials with a press.
- Informational
- Trialscount
- Trials in the scored run.
- Informational
- Planned Trialscount
- Trials the settings planned.
- Informational
Use and evidence
15 papers from 2021 to 2025 name this task in their title or abstract. That ranks it 426 of 495 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 4 |
| 2024 | 3 |
| 2023 | 4 |
| 2022 | 2 |
| 2021 | 2 |
| 2020 | 2 |
| 2019 | 3 |
| 2018 | 1 |
| 2017 | 1 |
| 2016 | 2 |
| 2015 | 2 |
| 2014 | 2 |
| 2013 | 0 |
| 2012 | 1 |
| 2011 | 1 |
| 2010 | 0 |
| 2009 | 0 |
| 2008 | 0 |
| 2007 | 0 |
| 2006 | 0 |
| 2005 | 0 |
| 2004 | 0 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 0 |
| 2000 | 0 |
Use grade E
Fewer than 30 papers from 2021 to 2025.
Evidence grade D
Little published measurement evidence found.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 1
- Registered clinical studies using it as an outcome
- 0
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 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Bar
- 64 px wide and 280 px tall, with a line across it four fifths of the way up. It waits empty for 1,000 ms (1,500 ms after a screen), then fills from the bottom at a constant speed, meeting the line at 800 ms and the top at 1,000 ms.
- Go trial
- The participant presses the space bar to stop the bar as close to the line as possible. For 1,000 ms a line under the bar then says how many ms before or after the line it stopped.
- Stop trial
- The bar stops by itself before the line, and the participant holds back until the bar would have filled; the line under it then says whether the press was held back.
- Stop time
- The stop-signal test's rule, a one-up one-down staircase: after a stop trial held back the next bar stops 25 ms later (standard, 25 to 100), after a press 25 ms earlier, from 500 ms (standard, 300 to 700), kept between 50 and 775 ms.
- Trials
- 5 blocks (standard, 3 to 8) of 30 go and 10 stop trials, each block in an order drawn from the session's seed, with a rest between blocks: 200 trials, 50 of them stop trials. First, 10 practice trials: 4 go, then 4 go and 2 stop trials stopping at the first stop time.
- Timing
- The bar is drawn on animation frames from the time each frame starts, and each press is timed by its key event on the same clock; the frames shown and dropped are saved.
- Score
- SSRT by the integration method with replacement of go omissions: the go press time at the rank of the share of stop trials pressed, minus the mean stop time. Beside it, the stopping error of go presses and the share of stop trials held back.
Because the line sets when a go press should come, waiting for the stop does not help. SSRTs from this design and from choice-reaction stop-signal tasks share only part of their variance, so compare SSRTs from the same task. Times include display and keyboard delays that differ between computers, and a session whose browser dropped more than 5% of the bar's frames is flagged. The scores support research and do not diagnose.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: go trials of anticipatory_inhibition_trial from the scored run, one press each to stop the bar on the line; stop trials are left out because their stop times adapt. A press has no correct option, so accuracy is not judged against chance. A go trial with no press before the bar fills is a missed response, and each press is timed from the bar's start. Missed go responses and responses under 100 ms follow the timed-test rule. Go presses 150 ms or more from the line on average, more than 5% of frames dropped while bars rose, and data that fail the race-model checks are flagged; the last two withhold the percentile.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. 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. A go press is timed to a line the bar meets at 800 ms, so presses that land far from it on average were not timed to the line. The consensus guide (Verbruggen et al. 2019, recommendations 7 and 9) advises against estimating SSRT when p(respond|signal) is outside 0.25 to 0.75, when go omissions are many or when failed-stop presses come later than go presses; the scorer's validSSRT checks these. The bar's motion is the go signal and its stop the stop signal, so a display that dropped frames changed both.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Blocks | 5 | 3 to 8 |
| First stop time (ms) | 500 | 300 to 700 |
| Stop time step (ms) | 25 | 25 to 100 |
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.
Cite and describe
Participants completed the Anticipatory Inhibition Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Slater-Hammel, 1960; Zandbelt and Vink, 2010), with the standard settings (blocks: 5; first stop time (ms): 500; stop time step (ms): 25). The main score was stop-signal reaction time (integration method with replacement of go omissions: the go press time at the rank of the share of stop trials pressed, minus the mean stop time).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Slater-Hammel, A. T. (1960). Reliability, accuracy, and refractoriness of a transit reaction. Research Quarterly, 31(2), 217-228. https://doi.org/10.1080/10671188.1960.10613098The anticipated response inhibition paradigm.
- Coxon, J. P., Stinear, C. M., & Byblow, W. D. (2006). Intracortical inhibition during volitional inhibition of prepared action. Journal of Neurophysiology, 95(6), 3371-3383. https://doi.org/10.1152/jn.01334.2005Stopping is harder the closer the stop comes to the planned response.
- Zandbelt, B. B., & Vink, M. (2010). On the role of the striatum in response inhibition. PLoS ONE, 5(11), e13848. https://doi.org/10.1371/journal.pone.0013848A rising bar stopped with a press at 800 ms, and a stop-time staircase in 25 ms steps.
- He, J. L., Hirst, R. J., Puri, R., et al. (2022). OSARI, an open-source anticipated response inhibition task. Behavior Research Methods, 54(3), 1530-1540. https://doi.org/10.3758/s13428-021-01680-9The bar's timing, the staircase's start, step and limits, and feedback after each trial.
- Verbruggen, F., Aron, A. R., Band, G. P. H., et al. (2019). A consensus guide to capturing the ability to inhibit actions and impulsive behaviors in the stop-signal task. eLife, 8, e46323. https://doi.org/10.7554/eLife.46323SSRT by the integration method, its checks and the number of stop trials.
Source papers
- Slater-Hammel (1960): the paradigm. Zandbelt and Vink (2010) and He and colleagues (2022): the rising bar, its timing and the stop-time staircase. Verbruggen and colleagues (2019): SSRT estimation and its checks.Paradigm source, Adults
Questions
How long does the Anticipatory Inhibition Task take?
About 11 to 13 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?
Stop-Signal Reaction Time, Stopping Error, Stop Trials Held Back, Signed Stopping Error, Go Press Time, Go Press Variability, Failed-Stop Press Time, Mean Stop Time, SSRT Checks Passed, Go Trials Missed, Anticipations, Presses Before the Bar Rose, Frame Interval, Dropped Frames, Go Trials, Stop Trials, Stop Trials Pressed, Trials and Planned Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Anticipatory Inhibition Task used in research?
15 papers from 2021 to 2025 name it in their title or abstract. That ranks it 426 of 495 test families in the ConductCognition test census (use grade E). Source: ConductCognition test census 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Anticipatory Inhibition Task have?
In the published research, 0 papers report its test-retest reliability and 0 registered clinical studies use it as an outcome (evidence grade D in the ConductCognition test census).
Which settings can a researcher change?
Blocks (3 to 8), first stop time (ms) (300 to 700) and stop time step (ms) (25 to 100). 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.
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