Simple reaction time - click the moment the screen turns green. Measures raw neural speed.
Simple reaction time is the fastest possible response to a single stimulus - a pure measure of neural conduction plus motor execution.
Elite human averages fall around 200 ms. Average adults land near 270-300 ms. Fatigue, caffeine, and even posture shift the number meaningfully.
We discard early button-presses as false starts because they reflect anticipation, not reaction.
Tracking your RT over weeks is a surprisingly sensitive marker of sleep and training load.
Galton first measured reaction time in the 1880s. It remains one of the most reliable behavioural measures in psychology.
Simple RT correlates modestly with general intelligence (r≈0.2-0.3) and strongly with alertness and age.
The total time from a visual flash to your finger leaving the button.
This task isolates the speed of a fixed stimulus-response loop: light hits the retina, signals travel to visual cortex, a motor command fires, and your finger moves. With only one stimulus and one response, there is no choice or decision stage, so your time mainly reflects neural conduction and motor execution rather than thinking.
Choice reaction tasks add a decision step and run roughly 100 milliseconds slower, while go/no-go tasks add inhibition. Here, nothing must be decided. Real-world correlates include the moment a sprinter leaves the blocks at a gunshot or a driver lifting off the accelerator the instant brake lights appear ahead.
Build a stable, anticipation-free response rather than chasing a single lucky click.
Run blocks of fifteen to twenty trials and track your median, not your fastest single time. Keep your finger resting lightly and your eyes fixed on the centre of the screen. Stay relaxed; tension slows the motor stage. Only judge progress once your median holds steady across several sessions on the same device.
The classic trap is anticipating the green and clicking early, which the random delay before each go signal exists to punish. A false start should reset the trial, never count as a fast one. Chasing the screen this way trades real speed for guessing, and your average gets worse, not better.
Read your typical time, then watch how it drifts day to day.
Simple visual reaction times for healthy adults commonly land around 200 to 270 milliseconds, with practised individuals dipping below 200. Browser and hardware lag add a fixed offset, so treat your own median on one device as the baseline. Strong performance looks like a low median paired with low trial-to-trial variability.
This number is highly state-dependent: sleep loss, caffeine, time of day, screen refresh rate and input lag can each shift it by tens of milliseconds. A single result tells you little. It does not measure intelligence, decision quality or accuracy under choice, only raw speed on this one narrow loop.