A small, dependency-free web game modeled on the Double Decision exercise (a Useful Field of View / speed-of-processing task). You identify a vehicle in the center of your vision and locate a Route 66 sign in your periphery — in a flash. As you improve, the flash gets shorter and your useful field of view widens.
Open-source educational re-creation. Not affiliated with or endorsed by Posit Science / BrainHQ. Not a medical device and not a treatment. See Important caveat.
No build step, no dependencies. Just open the file:
# from the repo root
open index.html # macOS
xdg-open index.html # Linux
# ...or serve it (recommended so localStorage/paths behave consistently):
python3 -m http.server 8000
# then visit http://localhost:8000Works in any modern desktop or mobile browser. Progress is saved locally in your
browser (localStorage) — nothing is uploaded anywhere.
- Mouse/touch: click the vehicle (Car/Truck), then click the spoke where the sign appeared.
- Keyboard:
C= car,T= truck;1–8= spoke position.
Each round has three phases, mirroring the real task:
- Fixate the crosshair in the center box.
- Flash — a car or truck appears in the center at the same time a Route 66 shield appears at one of 8 radial positions, mixed with distractor signs. Then a visual mask wipes the afterimage.
- Two decisions:
- What was in the center? (car vs. truck — trains central discrimination)
- Where was the Route 66 sign? (trains peripheral localization)
You have to get both right for the round to count as a success. That "divided attention across the whole field" is the point — it's what stretches the useful field of view outward.
- Exposure staircase. A 3-down/1-up staircase adjusts the flash time: three both-correct rounds in a row and the flash gets ~20% shorter; a miss and it gets ~28% longer. It converges on your threshold (~79% correct), reported in milliseconds — lower is faster processing.
- Stages (chooseable, or
Adaptiveto auto-ramp within a session):- Inner ring, no distractors
- Outer ring, no distractors
- Outer ring + 4 distractors
- Full field + 7 distractors
- Speed (ms): your threshold exposure — the headline number, lower = better.
- Accuracy: share of rounds where you nailed both targets.
- Stars + personal best + day streak, and a "protocol goal" of 10 sessions (see below).
The Double Decision task is the training vehicle for speed-of-processing training (SPT), studied most prominently in ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly), a large multi-site randomized controlled trial of healthy older adults.
- In ACTIVE, participants randomized to the speed-of-processing arm had about a 29% lower risk of dementia over 10 years than controls — and the effect scaled with the number of sessions completed. Notably, the memory and reasoning training arms did not show the same protective association.
- 2026 follow-up analyses of the ACTIVE cohort report the lower-dementia association persisting up to ~20 years after the original training, which was only ~10 core sessions (5–6 weeks) plus a few booster sessions.
That ~10-session structure is why this game frames a "protocol goal" of 10 sessions on the home screen. A handful of short sessions is the dose that was studied.
On "removing plaques": the strongest, most direct human evidence here is about reduced dementia/Alzheimer's risk and incidence in a behavioral trial — not about clearing amyloid-beta plaques. Amyloid clearance is what the recent anti-amyloid drugs (e.g., lenacemab-class antibodies, trontinemab, remternetug) target, and that's a separate line of research. Cognitive-speed training and anti-amyloid therapy are complementary but distinct; this game sits on the behavioral / cognitive-reserve side.
- The ACTIVE Study overview — Posit Science / BrainHQ: https://www.brainhq.com/world-class-science/information-researchers/active-study/
- Edwards JD et al., Speed of processing training results in lower risk of dementia, Alzheimer's & Dementia: TRCI (2017): https://www.sciencedirect.com/science/article/pii/S2352873717300598
- USF Health, Intervention becomes first to successfully reduce risk of dementia (2017): https://hscweb3.hsc.usf.edu/blog/2017/11/13/intervention-becomes-first-to-successfully-reduce-risk-of-dementia/
- Johns Hopkins Medicine, Cognitive Speed Training Linked to Lower Dementia Incidence Up To 20 Years Later (2026): https://www.hopkinsmedicine.org/news/newsroom/news-releases/2026/02/cognitive-speed-training-linked-to-lower-dementia-incidence-up-to-20-years-later
- Coe NB et al., Impact of cognitive training on claims-based diagnosed dementia over 20 years: evidence from the ACTIVE study, Alzheimer's & Dementia: TRCI (2026): https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/trc2.70197
- BrainHQ, Double Decision exercise page: https://www.brainhq.com/why-brainhq/about-the-brainhq-exercises/attention/double-decision/
This is a personal, educational re-creation of a well-studied paradigm. It is not the certified BrainHQ product used in the trials, it has not been clinically validated, and it makes no claim to prevent, treat, or reverse Alzheimer's disease or any other condition. The published risk-reduction findings come from a specific commercial protocol under research conditions; using a look-alike game does not guarantee any health outcome. If you have concerns about cognition or dementia risk, talk to a qualified clinician.
index.html # screens & markup
css/styles.css # theme-aware styling (light/dark)
js/game.js # engine: rendering, trial flow, adaptive staircase, persistence
docs/ # screenshots for this README
No frameworks, no network calls, no tracking. All rendering is plain Canvas 2D.
MIT — see LICENSE.