Cognitive games · working memory

Did this square appear 2 ago?

A square flashes on a 3×3 grid every 2.5 seconds. Hit Match (or press space) when the current position is the same as 2 trials ago. 25 trials. Pause anytime.

Press Start. Hit Match (or space) when this matches the position from 2 trials ago.

Round complete.

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Hits — False alarms — d′ —

How it works. Standard 2-back working memory task. d′ (d-prime) measures sensitivity — how reliably you tell matches apart from non-matches. d′ above 2 is strong; 1–2 is healthy; below 1 means working memory is loaded right now. ADHD adults often score lower than peers; medication and rest both move the number up. Don't over-interpret a single round — this is for pattern, not verdict.