Average reaction time: what's normal, by age

What is a normal reaction time?

Reaction time is the gap between something happening and you responding to it. The simplest version, called simple reaction time, is one signal and one response: a light comes on, you press a button.

The number you get depends a lot on how it is measured. In a large study published in 2015, David Woods and colleagues measured simple visual reaction time in 1,469 adults aged 18 to 65 with carefully calibrated equipment. The average was about 231 ms. After subtracting the 18 ms their own screen and mouse added, it was about 213 ms.

Other published studies have reported much slower averages, from around 230 ms to nearly 400 ms. Woods and colleagues argued that a lot of that spread comes from the hardware and software used to take the measurement, not from the people being tested.

200–250 ms

So a fair summary: for a healthy adult in a well-controlled test, a simple visual reaction time of roughly 200 to 250 ms is typical. On an ordinary phone or laptop, expect your score to read higher.

Reaction time by age

Reaction time gets quicker through childhood, peaks in young adulthood, and then slows gradually. The slowing in simple reaction time is gentle.

That works out at about half a millisecond a year, or around 5 ms a decade. A second group in the same paper, aged up to 82, showed a similar slope. The authors found that spotting the signal stayed about as fast with age; most of the slowing came from the movement side.

Geoff Der and Ian Deary (2006) looked at 7,130 adults in the UK Health and Lifestyle Survey and found a slightly different shape: simple reaction time changed little until about age 50, then slowed. Choice reaction time, where you must pick the right response, slowed steadily right across adult life. Both studies agree on the main point: in healthy adults, simple reaction time slows only modestly, and the gap between one person and another of the same age is often larger than the change from decade to decade.

Woods and colleagues found no meaningful difference between men and women in simple reaction time, and none by level of education.

Simple vs choice reaction time

A choice reaction task gives you more than one possible signal and a different response for each, such as "press left for red, right for blue". You now have to decide as well as react, so it takes longer.

In 1952, William Hick showed that choice reaction time rises with the number of options, roughly in line with the logarithm of that number. Going from two choices to four adds about as much time as going from four to eight. This is known as Hick's law.

Tasks that add conflict take longer still. In the Stroop test, you name the ink colour of a word that spells a different colour, and your reading habit gets in the way. Brainbay has both kinds of task, so you can feel the difference between pure speed and speed with a decision.

What slows you down

• Lack of sleep. A meta-analysis of 70 studies by Julian Lim and David Dinges (2010) found that short-term sleep deprivation hit simple attention hardest, with large increases in lapses: moments where your response is very slow or missing.
• Tiredness and time of day. Your speed varies across the day and drops as you tire.
• Alcohol and some medicines. Many slow reactions, which is why drink-driving laws exist. Check the leaflet for any medicine that warns about drowsiness.
• Distraction. A phone buzzing or a conversation nearby splits your attention.
• Anticipation gone wrong. Guessing when the signal will come leads to false starts, then hesitation.
• Cold hands and unfamiliar kit. A new mouse, a slippery screen or a cramped position all cost time.

Why online tests read slower

When you take a reaction test in a browser, the time on the screen includes your reaction plus the delays of the device. There are three main ones.

1. The display. The screen takes time to show the change. A screen that refreshes 60 times a second only updates every 16.7 ms, and the panel itself adds more.
2. The input. A mouse, keyboard or touchscreen takes time to notice your press and pass it on.
3. The software. The operating system and browser add their own processing on top.

These add up. Nicosia and colleagues (2022) used a robot to test 26 smartphones and found that the screen and touchscreen together added between 35 and 140 ms, with most phones between 60 and 90 ms. Phones with faster processors tended to have less display delay.

Browsers on computers are not immune. Pronk and colleagues (2019) measured web reaction tests under controlled conditions and found that response times were consistently overestimated. The average overestimate was about 58 to 70 ms on the phones and tablets they tested, and about 62 to 133 ms on the computers with keyboards, depending on the browser and operating system.

How to test yourself fairly

• Use the same device every time. The device delay is roughly constant, so your own changes still show up.
• Take several tries and average them. Single tries are noisy. Brainbay's reaction time test takes five tries and shows the average.
• Expect a random wait. A good test varies the delay before the signal, so you can't time it. Brainbay waits between about 1.4 and 4.2 seconds, and a tap before green just restarts that try.
• Sit comfortably, with your finger ready. Rest it on the screen edge or the mouse button.
• Close other apps. On a computer, a wired mouse and a screen with a high refresh rate may trim the delay.
• Test at a similar time of day, and not when you are very tired.

Brainbay times each tap from the input event's own timestamp against the frame where green was drawn, which removes some software delay. The screen and touch delay of your device are still in the number, as with any online test.

Can you get faster?

A little, mostly by practice on the task itself and by removing the things that slow you down. Your first few tries on any reaction test are usually your slowest, as you get used to the screen and the rhythm. Sleep is the big one: being well rested reduces lapses.

For aiming and moving the pointer quickly, try the aim trainer. For speed with a decision, try the Stroop test or the Schulte table. Getting better at these games is real, but it is a skill in those games. Whether it carries over to driving or sport is not something an online game can show (see Does brain training work?).

Sources

• Woods, D. L. et al. (2015). Factors influencing the latency of simple reaction time. Frontiers in Human Neuroscience, 9:131.
• Der, G. & Deary, I. J. (2006). Age and sex differences in reaction time in adulthood: results from the United Kingdom Health and Lifestyle Survey. Psychology and Aging, 21(1).
• Hick, W. E. (1952). On the rate of gain of information. Quarterly Journal of Experimental Psychology, 4(1).
• Lim, J. & Dinges, D. F. (2010). A meta-analysis of the impact of short-term sleep deprivation on cognitive variables. Psychological Bulletin, 136(3).
• Nicosia, J. et al. (2022). To BYOD or not: are device latencies important for bring-your-own-device (BYOD) smartphone cognitive testing? Behavior Research Methods.
• Pronk, T. et al. (2019). Mental chronometry in the pocket? Timing accuracy of web applications on touchscreen and keyboard devices. Behavior Research Methods.