Audio Reaction Time Test

Sound gets there first

An auditory signal reaches the parts of the brain that can act on it through a shorter chain than a visual one does. The ear converts pressure to nerve impulses almost immediately, whereas the retina performs a slower chemical conversion before anything is transmitted at all.

The consequence is that most people respond to a sound noticeably faster than to a light, and the gap is large enough to see plainly in a browser test rather than needing a laboratory to detect. Anyone who scores in the middle of the pack on the visual test will usually beat their own visual figure here.

This is why sprint starts and motor racing both use sound. A starting pistol is not tradition, it is the fastest available way to tell several people to move at the same instant.

What your audio path adds to the score

Audio has its own latency and it is usually worse than a display refresh. Bluetooth headphones are the extreme case: the codec buffers audio deliberately, and the delay can run to a couple of hundred milliseconds, which is comparable to the thing being measured.

Wired headphones or wired speakers are the right equipment for this test. The remaining delay is then the audio buffer the browser and the operating system keep, which is small enough to sit inside the margin printed beside your score, though it is not zero.

The tone is scheduled rather than simply played, so the moment it is due to become audible is known in advance instead of being guessed at from when the play command returned. That is the same reasoning as timing the visual test from the painted frame rather than from the instruction to paint.

Running the test without watching the screen

Nothing on screen changes when the tone plays, so watching the page cannot help you and looking away cannot hurt you. Closing your eyes is a reasonable way to make sure you are measuring hearing rather than catching some incidental flicker.

The volume is left where your system has it and the tone is a plain sine burst at a frequency that is easy to hear on cheap hardware without being unpleasant. If you cannot hear it, the fault is more likely to be a muted tab than the test.

Browsers will not produce sound until a page has been interacted with, which is a rule against autoplay rather than a bug here. The first click or key press starts the test and unlocks audio at the same time, so the sequence never stalls silently.

This is a measurement toy, not a medical or psychological test. No score here says anything about your health, attention or cognition, and it is not a screening tool of any kind.

Questions

Why is my audio reaction time faster than my visual one?

Because hearing reaches the brain through a shorter path than sight — the ear transduces sound almost immediately while the retina takes longer. The difference is consistent enough that most people beat their own visual score here.

Do Bluetooth headphones affect the result?

Considerably. Wireless audio is buffered on purpose and the added delay can be a large fraction of the score itself. Use wired output if you want the number to mean anything.

Why does nothing appear on screen?

By design — the stimulus is the tone alone, so there is nothing visual to react to early. Feel free to look away or close your eyes while a round is running.