A reflex is an involuntary or highly automatic response to a specific stimulus. Classic examples include the knee-jerk response examined with a reflex hammer and protective withdrawal from a painful stimulus.
The important point is that you do not wait for the stimulus, consciously identify it, decide to respond and then choose a button. The response pathway is designed to operate automatically.
Reaction time describes the interval between a defined stimulus and a measurable voluntary response. In a simple visual browser test, you are instructed to wait for the go signal and intentionally click when it appears.
That interval contains several stages: the stimulus must physically appear, you must detect it, the nervous system must prepare the movement, and your input device must register the action.
In gaming and sport, “reflexes” is often used informally to describe the ability to respond quickly under pressure. Those responses can involve anticipation, pattern recognition, decision-making, aim and learned motor habits—not just physiological reflex arcs.
So a player can have excellent game reactions because they predict situations early even if their simple browser reaction time is ordinary.
These are useful personal performance measures, but they should not be interpreted as neurological tests.
Calling every fast action a reflex can hide the skills you might actually want to improve. If you are slow because you misidentify a target, decision training may help more than repeatedly clicking a green screen. If you are accurate but take too long moving the cursor, aim mechanics may be the limiting stage.
Separating detection, decision and movement makes reaction training much more useful.
Not in the clinical neurological sense. It measures a voluntary response to a known stimulus through your device.
Some sensorimotor performance can improve with practice, but clinical reflexes and learned reaction tasks are not the same thing.
It is common informal language in gaming and sport, where “reflexes” often means rapid responses rather than a specific reflex arc.