Reaction Time
Measure how long it takes you to convert a visual signal into a finger movement — the classic simple reaction-time paradigm, run entirely in your browser.
How to run it
- 1.Press Start, then wait — the delay before the signal is randomised.
- 2.The moment the panel turns bright, click, tap, or press Space.
- 3.Do at least five trials; your median is more informative than your best.
Interactive demonstration
How this demonstration works
The demo records a high-resolution timestamp with performance.now() when the target appears and again when your input event fires, then reports the difference. The wait interval is randomised between 1 and 3.5 seconds so you cannot anticipate it. Clicking early is flagged and discarded.
What the science says
Simple visual reaction time in healthy adults typically falls in the 200-300 ms range, and roughly 20-80 ms of any browser measurement is display and input latency rather than biology. Reaction time varies within a single person across the day with sleep, caffeine, and arousal, which is why single trials are close to meaningless and medians across many trials are used in research.
Sources
Sponsor this work
BRAINMATTER is independent and reader-supported. These demos and the Visualizer Studio run entirely in your browser, with no tracking and no sign-up. A one-time sponsorship covers research time, editorial review, and hosting so we can keep publishing without paywalls.