Reaction Time
The interval between the presentation of a stimulus and the initiation of a response — a key measure of processing speed.
Simple reaction time — tap as fast as you can when a light appears — averages 200-250 milliseconds in young adults. That's one-fifth of a second between seeing and responding. Choice reaction time (picking between multiple options) is slower because your brain has to identify the stimulus AND select the right response. Reaction time is influenced by age, fatigue, sleep quality, stimulus intensity, and practice. It's been measured since the 1850s, making it one of the oldest metrics in experimental psychology, and it remains one of the most reliable indicators of neurological health and cognitive processing efficiency. The best part: it responds well to practice.
Frequently Asked Questions
What is a good reaction time?
For simple reaction time (one stimulus, one response): under 200ms is excellent, 200-250ms is average for young adults, 250-300ms is typical for older adults. For choice reaction time (multiple options): add 50-100ms. Age, sleep quality, and practice all influence these numbers. Competitive gamers average around 150-180ms.
Does reaction time slow with age?
Yes, but less than you'd think. Simple reaction time slows by roughly 1-2ms per year after age 20. The bigger decline is in choice reaction time — selecting the right response among options — which relies more heavily on processing speed and inhibitory control. Both are responsive to practice at any age.
Can you improve your reaction time?
Yes. Consistent practice with reaction-based tasks can improve response times by 10-20%. The gains come from both faster neural processing and more efficient motor preparation. Sleep quality has the single largest acute effect — reaction time after sleep deprivation can be 50% slower than after a full night's rest.