About Stroop Test Lab

What this site is

Stroop Test Lab offers eleven well-known tasks from cognitive psychology, starting with the Stroop test. Each one runs entirely in your browser, shows a detailed result, and keeps a private history on your device.

The goal is simple: make these tasks easy to try, easy to understand, and honest about what they can and cannot tell you.

Why it is free

There are no accounts, no paywalls and no premium tiers. The site is small and cheap to run because all the work happens in your browser.

If the site ever shows advertising to cover hosting costs, it will never appear inside a running test, and the privacy policy will be updated first.

How the tests are built

Every task follows a classic research design: the Stroop color-word task, the Eriksen flanker task, Go/No-Go, simple reaction time, digit span, spatial span, the N-back task and others.

Timing uses the browser high resolution clock. Stimuli appear in a single frame, and the clock starts on the frame where they are painted. Responses use the timestamp of your input event. Scoring follows standard methods, including d prime with a log-linear correction where it applies.

The limits of online testing

Browser tests are useful, but they are not lab instruments. Screens, mice, keyboards and touch panels add delays that vary between devices, often 20 to 80 milliseconds.

Results also depend on sleep, mood, age, language and practice. The result bands on this site are our own guidance, not population norms, and nothing here is a medical or psychological diagnosis. If you have concerns about your attention or memory, please talk to a qualified professional.

Your privacy

Your results never leave your device. They are stored in your browser and you can export, import or delete them at any time from the History page. Read the full privacy policy for details.

Contact

Questions, corrections or ideas for new tests are welcome. Write to hello@example.com.