How to play · 3 min read
Dual N-Back Explained: Position and Sound Matches
Understand Dual N-Back with a turn-by-turn N=2 example, Position and Sound controls, common matching mistakes and HumanCalc's progression rule.
Read guideFlash Recall — Test Your Visual Short-Term Memory
Remember the direction. Rebuild the sequence.
- Working memory
- 3 min
- Medium
A sequence of E and mirrored Ǝ shapes appears briefly. Rebuild their exact order as the sequence grows, exposure shrinks and the shapes gradually join together.
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Difficulty map
From level 1 to the final stop. Percentages come from real HumanCalc players.
- Stop 1 of 15, Easy: level 1.
- Stop 2 of 15, Easy: level 2.
- Stop 3 of 15, Easy: level 3.
- Stop 4 of 15, Easy: level 4.
- Stop 5 of 15, Easy: level 5.
- Stop 6 of 15, Medium: level 6.
- Stop 7 of 15, Medium: level 7.
- Stop 8 of 15, Medium: level 8.
- Stop 9 of 15, Medium: level 9.
- Stop 10 of 15, Medium: level 10.
- Stop 11 of 15, Hard: level 11.
- Stop 12 of 15, Hard: level 12.
- Stop 13 of 15, Hard: level 13.
- Stop 14 of 15, Hard: level 14.
- Stop 15 of 15, Hard: level 15.
EasyLevels 1–5
MediumLevels 6–10
HardLevels 11–15
How it works
1The complete sequence appears in one brief visual display.
2It vanishes before you can keep rereading it.
3Rebuild E and Ǝ in order. Higher levels bring the shapes closer together.
How to play
- 1
Take one snapshot
E and mirrored Ǝ shapes appear together. Remember the orientation of each shape.
- 2
Hold the order
Use the E and Ǝ buttons, or keyboard E and R, to reconstruct the sequence. Press Enter to check.
- 3
Adapt to the load
Two correct recalls move you up. Higher levels add shapes, shorten exposure and tighten spacing; from level 12 the shapes touch.
What it trains
Hold and update information while under load. Brief displays leave a rapidly fading visual trace; exact-order recall then adds short-term working-memory demand.
- Practice focus
- Working memory
- Based on
- Sperling, 1960; Luck & Vogel, 1997
Research background
These sources describe related tasks or concepts. HumanCalc adapts them for browser practice; a game score is not a clinical result.
Leaderboard
A new season every week. The overall top three earn a medal and bonus XP. How scores work. Scores here show as Lvl 5.
Leaderboard
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Questions
What does Flash Recall measure?
It combines brief visual exposure with immediate serial recall, so performance depends on visual encoding, attention and short-term order memory.
Is this a photographic-memory test?
No. It is a task-specific visual-memory exercise and does not diagnose or promise photographic memory.
Why do later levels disappear faster?
Shorter exposure limits repeated reading, while longer sequences increase how much ordered information must be retained.
Learn the rules and practise
Research & scores · 2 min read
Does Brain Training Work? What Your Game Score Can Tell You
Separate improvement on a practiced game from broader cognitive claims. Read primary research links and learn how to compare HumanCalc scores fairly.
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