REACT OR STOP · 20 TRIALS
Follow each arrow—unless a red STOP signal appears. Then withhold your response.
Complete 20 trials: 16 arrow responses and 4 stop signals. Mistakes still advance.
READY?
Press ← or A for left, and → or D for right. If STOP appears, press nothing.
Keyboard: ← / A for LEFT · → / D for RIGHT. Touch: use the two large buttons. STOP means do not press either one.
HOW TO PLAY
When an arrow appears, prepare to choose its direction as quickly as you can.
Press left or right—unless the arrow is followed by a red STOP signal.
For a STOP trial, withhold both responses until the trial ends. Standard mode always runs for 20 trials.
ABOUT THE TASK
Most trials ask for a quick left or right response. On a minority of trials, a stop signal appears shortly after the arrow and asks you to cancel that prepared response.
That makes this different from a simple reaction test: speed matters, but so does response inhibition. This browser game is recreational, not a clinical or diagnostic assessment.
READ YOUR RESULT
Your accuracy includes correct arrow choices and successful stops. Average reaction time uses correct go trials only, so deliberate holds do not inflate it.
A fast device or input can affect timing. For a useful personal comparison, repeat the test on the same device and input method.
QUESTIONS
Do not press left or right. Wait until the trial completes; successfully withholding both responses counts as correct.
The short delay gives you time to prepare the arrow response before being asked to cancel it. That conflict creates the response-inhibition challenge.
There are exactly 4 stop trials and 16 go trials in a balanced 20-trial sequence. The stop trials are spaced across the run.
Not in standard mode: wrong directions, missed arrows, and failed stops count against accuracy but still advance. In endless mode, the first mistake or timeout ends the run.
Yes. Use the two large direction buttons. On desktop, use the arrow keys or A and D.
No. It is a recreational reaction game and cannot diagnose attention, impulse-control, neurological, or other health conditions.