Go/No‑Go Test
READY
Press Start. Click on green. Hold still on red.
Trial log
0 entriesGreen means go, click as fast as you safely can. Red means no-go, the correct move is to do nothing and let it pass. Clicking early, before either light appears, is logged as a false start and doesn't count toward your eight trials. This is a simplified, for-fun version of a lab paradigm researchers use to study attention and impulse control, not a diagnostic or clinical test.
You just did something a little counterintuitive: the hard part of this test wasn't reacting fast, it was doing nothing at all. Most reflex tests only ever ask you to go. This one asks you to go most of the time, and then, without warning, to stop yourself from doing the thing you were just primed to do. That's a genuinely different skill, and your errors here tell a more interesting story than a single speed number ever could.
What Is a Go/No-Go Test?
Researchers use Go/No-Go tasks to study response inhibition, the ability to stop an automatic action once it's already been triggered. The setup is deliberately lopsided: most trials are "go" trials, roughly 75% in this version, which trains your brain to expect a signal that means click. The remaining "no-go" trials, the other 25%, ask you to override that expectation and do nothing instead.
That imbalance is the whole point. If go and no-go trials appeared equally often, withholding wouldn't be difficult, you'd simply be waiting to see which one showed up. By making "go" the default, the test builds a genuine urge to respond, so a no-go trial is actually testing whether you can catch and cancel that urge in real time.
Why Withholding Is Harder Than Reacting
Once your brain has built up an expectation, in this case "a light is about to appear and I'm going to click it", cancelling the planned action takes extra processing on top of simply perceiving the signal. Psychologists call this a prepotent response, an action that's become the default, automatic choice. Stopping it requires an additional inhibitory step your nervous system doesn't need for a plain go response, which is exactly why no-go trials feel harder even though, on paper, doing nothing should be easier than doing something.
It's also why speed and caution trade off against each other here. Click too eagerly and you'll rack up false alarms on the red trials. Hang back too cautiously and you'll start missing genuine green trials because you hesitated. The sweet spot is a kind of controlled quickness, ready to act, but not on autopilot.
What Your Errors Actually Mean
The two error types in this test aren't interchangeable, they point in different directions. A false alarm, clicking on a red no-go trial, is a commission error, and it's the primary sign of inhibitory failure: your brain fired off the click before the stop signal could catch up with it. A missed trial, no click on a green go trial, is an omission error, and it usually points to a lapse in sustained attention rather than a control problem, you weren't too impulsive, you just weren't watching closely enough in that moment.
Worth being upfront about something: this is a simplified, browser-based version of a genuine research paradigm, not a clinical instrument. Real assessments of attention and impulse control involve trained clinicians, standardized conditions, and a lot more than eight trials. Treat your score as an interesting personal data point, not a diagnosis.
What Affects Your Score (and How to Improve It)
Arousal level matters more than most people expect. There's a well-established relationship in psychology, often called the Yerkes-Dodson law, where performance on tasks like this peaks at a moderate level of alertness. Too relaxed and you'll miss go trials from inattention. Too wound up, over-caffeinated, anxious, rushing, and you'll fire off false alarms because your impulse control is already stretched thin. The best runs tend to come from a calm, focused, slightly-alert state, not a jittery one.
Fatigue drags accuracy down specifically on the no-go trials first, since inhibition is more effortful than simple reaction and tires out faster over a session. And genuine practice does help here, unlike a pure reaction time test, because you're partly learning to recognize your own urge to click a split second before you act on it, which is a skill that transfers a little more broadly than muscle memory does.
Frequently Asked Questions
What's a good score on a Go/No-Go test?
Accuracy above 90% across both go and no-go trials is a strong result. Most healthy adults land somewhere in the 80-95% range on a short run like this one; below 70% usually means the test caught you either rushing or distracted rather than reflecting a lasting problem.
What's the difference between a false alarm and a missed trial?
A false alarm is clicking on a red no-go trial, a commission error that signals a lapse in inhibition. A missed trial is failing to click on a green go trial, an omission error that usually signals a lapse in attention rather than control. They're different mistakes with different causes.
Can this test diagnose ADHD or impulse control problems?
No. This is a simplified, for-fun version of a lab paradigm researchers use to study attention and inhibition, not a diagnostic tool. If you're genuinely concerned about attention or impulse control, the right next step is talking to a healthcare professional, not a browser test.
Why do I keep clicking on the red light even when I'm trying not to?
Because most trials are "go" trials, your brain builds a strong expectation that a signal means click, and that automatic urge is already in motion by the time you consciously register the color is red. That's the entire mechanism this test is designed to probe, it's not a personal failing, it's how prepotent responses work.
Does caffeine help or hurt performance on this kind of test?
It depends on your starting state and the dose. A small amount can sharpen attention and reduce missed go trials if you're tired. Too much tends to push you past the optimal alertness point and increases false alarms instead, since it's easier to fire off a click impulsively when you're wired.
Why does clicking too early get logged as a false start?
Clicking before either light appears means you're responding to anticipation rather than to an actual signal, so it can't be scored as a correct go or a correct withhold. It's logged separately and doesn't count toward your eight trials, the same way a false start works on a standard reaction time test.
Run it again and see if you can push your accuracy up — your best run is saved automatically in your browser, no sign-up required.