Five ways to measure a mind.

Estimate exactly ten seconds without counting. Reveals internal chronometry.

Study a scene, then identify the single element that shifted after a brief blackout.

Nine nodes light up in a growing sequence. Recall each step in order.

Rapid comparisons across numbers, words, and shapes. Measures cognitive throughput.

Abstract puzzles that measure fluid intelligence and rule inference.

Read a passage that disappears, then answer under time pressure. Measures reading speed and comprehension.

Deduction, probability, and hidden assumptions. No trivia — only reasoning under a 55-second clock, with confidence calibration.