Attention and Control
Most of the time you press. Sometimes you must not. The Go/No-Go test measures how well you stop a response that has already become a habit.
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Each square carries both a color and a symbol, so the task works for people with color vision differences too.
Every square appears in a single frame and its onset is taken from the paint, not from when the code ran.
Go/No-Go designs have been used for decades to study response inhibition in labs around the world.
Use the Space bar on a computer or a large tap pad on a phone or tablet.
Everything is stored in your browser only. No account, no tracking of your scores.
Beyond hit and false alarm rates you get d prime and criterion, the measures researchers use.
Easy, Medium and Hard change the pace, so you can find a level that challenges you.
How often you pressed on a red No-Go square. This is the main measure of impulse control.
How it is calculatedNo-Go presses divided by No-Go squares
Your average speed on green squares you responded to in time.
How it is calculatedAverage reaction time on hits, excluding responses under 150 ms
How often you caught or missed green squares. Many misses suggest you slowed down too much.
How it is calculatedHits or misses divided by Go squares
d prime shows how well you tell Go from No-Go. Criterion shows whether you lean toward pressing or holding back.
How it is calculatedz(hit rate) minus z(false alarm rate), with log-linear correction
These bands are site-defined guidance for adults on a desktop computer or a recent phone. They are not population norms and not a diagnosis.
| Band | Range | What it means |
|---|---|---|
| Excellent | below 10% | You stopped on almost every red square. |
| Good | 10-19% | Strong control with occasional slips. |
| Average | 20-34% | The habit of pressing sometimes won. |
| Needs practice | 35% or more | Try a calmer, more deliberate pace. |
| Band | Range | What it means |
|---|---|---|
| Fast | below 300 ms | Very quick responses to green. |
| Typical | 300-399 ms | A common speed for this task. |
| Slower | 400 ms or more | Careful, or slowed by device lag. |
| Band | Range | What it means |
|---|---|---|
| Excellent | 3.0 or more | Go and No-Go are clearly separated. |
| Good | 2.0-2.9 | Reliable discrimination. |
| Average | 1.0-1.9 | Some confusion between the two. |
| Needs practice | below 1.0 | Responses are close to guessing. |
The Go/No-Go task measures response inhibition: the ability to cancel an action you are about to make. Because most trials ask you to press, pressing becomes the default.
Stopping on the rare No-Go trial means overriding that default in a fraction of a second.
If Go and No-Go trials were equally common, the task would be a simple choice. Making Go trials frequent builds a prepotent response, a habit that is hard to stop.
That is why this test uses 75 percent Go trials and never shows more than three No-Go squares in a row.
Speed alone can hide a lot. Someone who presses on everything has perfect hits but terrible control. Someone who presses on nothing never makes a false alarm but misses every Go.
d prime combines both kinds of error into one sensitivity score, and criterion shows which way you lean. Together they describe your strategy fairly.
Fatigue, alcohol, stress and distraction all raise false alarms. Pace matters too: the Hard level gives less time, which makes stopping harder.
People also trade speed for control. Going slightly slower usually cuts false alarms, so compare sessions with similar Go reaction times.
Criterion describes your bias. A positive value means you tend to hold back, so you miss some Go squares but make few false alarms. A negative value means you tend to press, so you catch almost every Go square but also press on more red ones.
Neither bias is wrong in itself. In daily life the best setting depends on the cost of each mistake. On this test, a criterion close to zero with a high d prime is a balanced result.
Go/No-Go tasks appear in studies of impulsivity, attention, aging and the effects of sleep loss on self-control.
The task is a simple way to show students the difference between starting an action and stopping one.
Short sessions help you notice how tiredness or rushing changes your ability to hold back.
Researchers use standardized versions as part of wider assessments. This online version is not a diagnostic tool.
Keep your finger near the key or pad but not pressing. A heavy hand makes stopping harder.
The check and cross are large. Some people find shapes easier to react to than colors.
The order is random. Waiting to see the square, even briefly, beats guessing the rhythm.
Medium is the default for comparisons. Move to Hard once your false alarm rate is low.
It is a reaction task with two kinds of trial. On Go trials you respond quickly. On No-Go trials you hold back. It measures how well you stop a habitual response.
Squares appear one at a time in the center. Green with a check means press Space or tap the pad. Red with a cross means do nothing. Only your first press on each square counts.
Practice runs for 45 seconds, Standard for 2 minutes and Challenge for 3 minutes.
Yes. Press P, use the pause button, or switch tabs. The interrupted square is discarded. Stop shows your result if you completed at least 20 trials.
Any modern browser. A physical keyboard gives the most consistent timing, but the tap pad works well on phones.
A low false alarm rate means strong inhibition. Mean Go RT shows speed. d prime combines both kinds of error into one sensitivity score.
On this site a false alarm rate below 10 percent is Excellent, and a d prime of 3 or more is Excellent. These are site guidance bands, not clinical norms.
Use the History link in the menu or the View history button after a session. Results are compared within the same difficulty level.
It is saved only in your browser. Nothing is sent to a server.
Reload the page. If Space scrolls the page, click inside the test area first. Private browsing may stop results from being saved.
d prime compares your hit rate with your false alarm rate. If you caught nearly all green squares and pressed on only a few red ones, the two rates are far apart and d prime stays high.
Results depend on age, device, sleep, language, mood and practice. Average several sessions before drawing conclusions. This is not a medical or psychological diagnostic tool.
It takes about a minute. Your results stay private in this browser.