Attention & Control

Stop

The pymetrics (Harver) Stop game is a rapid go/no-go task—not a stop-signal task. You respond to red circles and withhold on green circles while repeated go trials build response momentum.

About 2 minutes
80 circles
Spacebar; full-width red/P tap button on touch devices

How to Play

01

Press the spacebar when a RED circle appears. Do nothing when a GREEN circle appears.

02

Every red circle also has stripes and a P; every green circle has dots and an H, so the rule never depends on color alone.

03

Each circle lasts briefly. A missed red and a press on green both count as errors.

04

On a touch device, use the full-width TAP FOR RED / P button in place of the spacebar.

In the real assessment

The real assessment is generally described as showing no right/wrong feedback. This practice version flashes a subtle ✓ or ✕ after each circle; the exact real trial count remains unconfirmed.

Skills Assessed

Response InhibitionSustained AttentionVigilance

Pro Tip!

Want to master this game? Read our expert guide for winning strategies and insights.

Read the Stop Guide

GameAssessmentPrep is an independent practice platform. We are not affiliated with pymetrics, Harver, or any employer. Our simulations are reconstructions for practice purposes.