Reflex Lab

A reaction & cognition self-test lab — measure your baseline, spot off days. On-device.

Simple reaction time for a visual stimulus sits around 200 to 250 milliseconds for most adults, and choice reaction — where you must decide which response — is meaningfully slower, a relationship formalised as Hick's law.

The useful measurement is not your best score but your own baseline and its variability. Reaction time is sensitive to sleep debt, alcohol and fatigue, and the effect shows up in consistency before it shows up in the average — the slow trials get slower while the fast ones stay fast. That makes variance the more honest indicator of an off day.