Switch

Every card is a coloured shape and the banner decides what counts — COLOUR? or SHAPE? The rule keeps flipping, and your brain pays for every flip in milliseconds. That toll is the switch cost, the measure cognitive scientists have used since the nineties for how fast a mind changes gears.

Everyone pays a switch cost — the interesting number is yours across the week, not once. It grows with fatigue and shrinks a little with practice, which makes the sleep calculator the honest companion tool, and the glossary has the vocabulary if “task switching” sent you curious. Race Vigil next, or head back to the Lab.