Reaction + inhibition

Go / No-Go Test

Green means go: react. Red means stop: do nothing. Sounds easy until the green ones lull you into a rhythm and a red one slips through. This is the go/no-go test, and it measures not just your speed but your brakes: how well you can stop a reaction you’ve already started.

24 trials: 70% are green GO signals
Hold on red: Tapping it is a commission error
0 red taps: Flawless impulse control

Go / No-Go

Tap on green. Do nothing on red. Press to start.

Speed is only half the test

A normal reaction test rewards one thing: going fast. But going fast is easy when going is all you ever do. The moment some signals mean don't, the task gets honest. Your brain builds a habit out of the green ones (react, react, react), and that momentum is exactly what trips you up when a red one appears. Stopping a reaction you've already begun is a different, harder skill, and it lives in a different part of the brain than the reacting does.

Those mistaken taps on red (commission errors) are the number psychologists actually care about. They are a clean, simple window into impulse control, which is why versions of this test show up in research on attention and self-regulation. Here, treat them as a score to beat: can you stay fast on green without getting sloppy on red?

Two ways to be wrong, and only one of them feels bad

A go/no-go task can go wrong in two directions, and the test scores them separately because they mean opposite things:

Error	What you did	What it usually means
Commission	Tapped on a NO-GO signal	Too little restraint. The habit fired before you could stop it.
Omission	Missed a GO signal	Attention lapse, or you were braced so hard for red that green got slow.

The reason both matter is that you can trade one for the other at will, and your reaction time moves with them. Hold back and your commission errors fall while your GO times get slower and your omissions creep up. Push hard and your GO times drop while red starts catching you. A score of 290 ms with two commission errors is not obviously better or worse than 340 ms with none; they are two points on the same curve.

So read your result as a pair, never as a single number. The interesting question is not "how fast was I", it is "how fast was I for that error rate". If you want the version of this without the braking problem, the simple reaction test removes the NO-GO signal entirely, and the choice reaction test keeps a decision but never asks you to withhold.

How to do well

Don't pre-load. If your finger is already twitching before the signal, red will catch you.
Stay even. The temptation is to speed up after a run of greens. That's exactly when a red sneaks through.
Accept a little slower. A touch more caution on green for far fewer red mistakes is usually the better trade.

Good to know

Frequently asked questions

What does the go/no-go test measure?

Two things. Your go reaction time (how fast you respond to the GO signal) and your response inhibition, how often you wrongly react to a NO-GO signal. Those mistaken reactions, called commission errors, are the real point: they show how well you can stop an action mid-impulse.

Why do I keep clicking on the red ones?

Because most signals are GO, your brain settles into a "react" habit, and stopping that habit takes active effort. When a NO-GO appears, the urge to respond is already in motion. Catching it is the skill the test trains, and tiredness and distraction make it noticeably harder.

How is this different from a normal reaction test?

The standard reaction test only measures going: you always react. Go/no-go adds the harder half: not reacting when you shouldn't. It is closer to real situations like driving, where stopping a planned move matters as much as making one.