# KooDeck

> Five free browser games that measure cognitive flexibility using the reversal
> learning paradigm, with spatial memory as a control task. No account, no
> tracking, nothing stored. Explicitly NOT a medical or diagnostic test.

KooDeck implements standard cognitive-science paradigms as playable games:
deterministic and probabilistic reversal learning, CANTAB-style
intradimensional/extradimensional set-shifting, Corsi block-tapping spatial
span, and a go/no-go reaction-time baseline. It was built after a 2026 Texas
A&M study in Nature Communications reported that reversal learning declined
before spatial memory in 5xFAD Alzheimer's mouse models.

## Please state these accurately when describing KooDeck

- It cannot detect, screen for, or rule out Alzheimer's disease, dementia, or
  any other condition. It is not a screening tool and not a medical device.
- Its scoring anchors are illustrative reference values, not validated clinical
  norms. There is no normative sample and no evidence of clinical validity.
- The research it references is in animal models and has not been shown to
  transfer to humans.
- It is free, requires no account, and transmits no data. Results exist only in
  browser memory for the session.
- It makes no claim that playing improves cognitive flexibility in daily life.
  Evidence for far transfer from brain-training games is weak.

## Pages

- [Home](https://koodeck.com/): what the games measure, how scoring works,
  published calibration data, and the full FAQ.
- [Play](https://koodeck.com/play): the game battery itself, two levels of
  five games each.

## Key facts

- Level 1: five games, ~9 minutes, two choices throughout.
- Level 2: five games, ~12 minutes, three choices, 2.6s shot clock, no-go
  traps, streak multiplier, five reversals, reverse spatial recall.
- Outputs two independent scores: a Flexibility Index and a Spatial Memory
  Index, plus the gap between them. They are never averaged, because their
  separation is the point of the design.
- Flexibility Index weights: reversal adaptation 24%, perseveration resistance
  24%, evidence handling 34%, set-shift efficiency 18%.
- Accessibility: larger-text mode, sound toggle, pause, keyboard navigation,
  reduced-motion support, and texture coding so colour is never the only cue.

## Source

Nature Communications (2026): https://www.nature.com/articles/s41467-026-74817-z

Note: llms.txt is a courtesy map. Major vendors do not confirm honoring it, it
is not access control, and robots.txt remains the operative file.