Two groups of dots flash briefly side by side. Click the side with more dots. Tests your Approximate Number System (ANS) — the innate ability to quickly estimate quantities without counting. Based on Dehaene's (1997) “The Number Sense” and Weber's Law.
How to Play
• Two clouds of dots appear side by side
• Click the side with MORE dots — or press A / ← for left, D / → for right
• Respond quickly — dots disappear automatically
• Harder levels show quantities that are closer together (harder ratios)