The colored tag above the number shows the current rule — alternating between parity and magnitude. Pick the correct answer as fast as you can.
Why it matters
The ability to quickly switch between different rules or tasks is a key executive function — in the real world we rarely do just one thing after another, we constantly have to shift context and strategy. The switch cost (the reaction-time gap between "switch" and "repeat" trials) is a reliable marker of cognitive flexibility.
Mental flexibility — the ability to quickly switch between two different rules without losing accuracy or speed.
Athletes in situations requiring a fast strategy change (transitioning from defense to attack), and anyone wanting to train cognitive flexibility.
Rating scale
The test is based on the classic task-switching paradigm (Jersild, 1927; Rogers & Monsell, 1995) — commonly used to measure cognitive flexibility. Healthy adults typically show a "switch cost" of 100–300 ms — reacting that much slower on trials where the rule changed from the previous one.