N-back (2-back) — Global Mind Tests

Measures selective updating and interference control: you maintain a sliding window of two items and decide whether the new one matches the earlier pattern.

Examples: A → B → A = match; C → D → C = match; D → E → F → F = no match (that’s 1-back, not 2-back).

What 2-back tells you

It probes your ability to continuously update a small buffer while suppressing interference from recent but irrelevant items. That’s key for reading span, multi-step instructions, and complex problem solving.

How scoring works

Points: each hit and each correct rejection = 1 point (max 30).
Speed factor: computed from the mean RT of hits only, clamped for stability.
Final score: raw = points × speed factor; then normalized to a 0–100 scale.

Training notes

Short daily sets beat occasional marathons; fatigue inflates false alarms.
Keep posture and breathing steady; micro-tension slows reactions.
Vary letters or add distractors only after your baseline stabilizes.