Goal

Symbols appear one at a time. For each one, tap Same if it matches the symbol from N steps back, or Different if it doesn't. You start at 1-back: does it match the one just before?

Rules

• Every symbol needs an answer. If you don't tap in time, it counts against you.
• The first N symbols of each level just need remembering — nothing to compare yet. The clock pauses for them.
• Catch the matches without false "Same" taps and you move up to 2-back, 3-back and 4-back. Struggle and you move back down.
• Watch for near misses: a symbol that matches 1 or 3 steps back isn't a 2-back match.

Scoring

Same on a real match: 10 × N. Different, correctly: 3 × N. A false Same or a missed match: −5. No answer on a non-match scores nothing and breaks your streak. Only real attention scores — tapping one button all game gets you nowhere.

Working Memory Updating

N-back is the most widely studied working-memory training task. You have to hold the last few items, compare, and drop the oldest — constantly. That updating skill underpins reasoning, reading comprehension and staying on track in conversation.

Interference Control

Near-miss symbols feel familiar but are wrong. Resisting them trains your ability to separate "seen recently" from "seen exactly N ago".