Average Reaction Time by Age (in Milliseconds) and What It Says About IQ

The average human reaction time to a visual signal is about 215 to 240 milliseconds in a calibrated laboratory and 273 ms on Human Benchmark's online test, whose median covers more than 81 million clicks. Age slows it by about 0.55 ms for each year between the twenties and the sixties, roughly 22 ms in all, which is less than the gap between one device and another. The link to IQ is real but modest: -.31 for simple reaction time and -.49 for four-choice in 900 people aged about 56. This guide gives the averages by age and by score in milliseconds, what the correlation means in IQ points, and why the claim that Victorians were quicker, and so cleverer, is contested.

What is the average reaction time in milliseconds?

Human Benchmark, the most-used online reaction test, says on its statistics page that the median reaction time is 273 milliseconds and the average is 284, from more than 81 million recorded clicks. Those are clicks, not people, and the pages we read give no count of users. Its test page warns that while an average human reaction time may fall between 200 and 250 ms, your computer could be adding 10 to 50 ms on top, and some modern TVs add as much as 150 ms. Its statistics page calls 30 ms a typical lag for a desktop or laptop and says phone taps run slower than clicks.

Laboratory and survey figures differ. Woods and colleagues (2015) measured 1,469 adults aged 18 to 65 on a calibrated mouse task and found a mean simple reaction time of 231 ms, or 213 ms after correcting for hardware delays; a second sample of 189 adults aged 18 to 82 gave 238 ms, or about 220 ms after the same correction. A survey of 900 people aged about 56 in the West of Scotland, using a nurse-run keypad device, found a mean of 358.2 ms (standard deviation 119.7) for simple reaction time and 727.8 ms for four-choice. Simple reaction time is one button for one signal; four-choice means picking the right one of four.

• Woods et al. 2015, calibrated lab sample, ages 18 to 65: 213 ms corrected (231 ms raw)
• Other large studies tabulated by Woods and colleagues: from 233 ms (4,896 people aged 20 to 59) to 397 ms (196 people aged 20 to 89), depending on the equipment
• Human Benchmark, median of online clicks, device lag included: 273 ms
• Der and Deary 2017, Scottish keypad survey, age 30: 290 ms
• Deary, Der and Ford 2001, West of Scotland keypad survey, age about 56: 358 ms
• MindCrowd web study, ages 40 to 70: 479 ms

The method moves the number more than the person does. Same-age adults range from 233 to 397 ms across these studies, while the entire age effect between 18 and 65 in the best-controlled one is about 22 ms. That is why a result in milliseconds means little without the device it came from.

What is the average reaction time by age?

The best-controlled age data come from Woods and colleagues. Latencies rose by 0.55 ms for each year of age and were unaffected by sex or education. The raw means by age group, from their Table 2, are below; subtract about 18 ms for the true latency once hardware delays are removed.

• Ages 18 to 24: 218 ms (about 200 ms corrected)
• Ages 25 to 31: 221 ms
• Ages 32 to 38: 225 ms
• Ages 39 to 45: 228 ms
• Ages 46 to 51: 234 ms
• Mid-fifties (the paper's group is printed as ages 51 to 58): 236 ms
• Ages 59 to 65: 239 ms (about 222 ms corrected)

The paper does not cover ages above 65 in a table we could verify, and a survey on different equipment gives higher figures. In the Scottish Twenty-07 study, which used a portable keypad, mean simple reaction time was 290 ms at age 30, 318 ms at age 50 and 354 ms at age 69; four-choice reaction time was 539, 623 and 729 ms. Their detection-time measure averaged 131 ms and did not change with age, which led Woods and colleagues to conclude that age-related slowing is due primarily to slowed motor output, not slower perception. Over 30 years the slope adds 16.5 ms, our arithmetic.

Der and Deary's 2006 analysis of 7,130 adults in the UK Health and Lifestyle Survey found that simple reaction time shows little slowing until around age 50, whereas choice reaction time, where the person must pick between responses, slows throughout adult life. It also found significant sex differences, most notably in the variability of choice reaction time. Studies disagree on sex differences in the simple task: Woods found none, while the web-based MindCrowd study found men about 34 ms quicker. Our guide to the age at which intelligence peaks covers how other abilities move across the lifespan.

What is the average reaction time for a 13, 14, 16 or 18 year old?

No study we could read gives a clean simple-reaction-time average for each of those single ages, so a chart that does is extrapolating. What exists points one way: by the early teens a typical person is about as fast as a young adult. On one response-conflict task, the median time was 265.6 ms for ages 13 to 15 and 270.6 ms for ages 21 to 28 (a difference that did not reach significance), against 292.6 ms for ages 9 to 11 and 313.4 ms for ages 66 to 76 (Thurm and colleagues, 2020). On a ten-minute vigilance task the median fell from about 544 ms at age 6 to about 326 ms at age 11 (Venker and colleagues, 2007). For a teenager, the honest answer is the young-adult figure for the equipment in use: about 215 to 225 ms in a calibrated lab and about 270 to 290 ms on an ordinary online test.

Is 213 ms, 181 ms or 270 ms a good reaction time?

It depends on the device, so read each score against the benchmark it matches. Here is how common results compare with the studies above:

• Under 150 ms: faster than every group average in the sources above. World Athletics treats a reaction under 0.100 second as a possible false start, so on a web test this is usually an anticipated click or one lucky trial
• 172 to 189 ms: quicker than any group mean we read; Galton's figures from the 1880s were 181 to 189 ms. Fine as a single click, rare as an average of many trials
• 200 ms: about the corrected mean of the youngest Woods group, and well ahead of Human Benchmark's median of 273 ms
• 213 ms: the corrected mean for all adults aged 18 to 65 in the Woods sample. Average for a calibrated lab, and quick on an ordinary computer
• 220 to 222 ms: the corrected means of the oldest Woods group (222) and of their second sample (about 220)
• 238 ms: the raw mean of the second Woods sample, so average for the lab
• 250 ms: slightly quicker than Human Benchmark's median; normal for a web test
• 270 to 273 ms: Human Benchmark's median; by its own note about 30 ms of that is typical screen and mouse lag
• 300 ms (0.3 seconds): 27 ms slower than Human Benchmark's median, and typical of a keypad survey at ages 30 to 50 (290 and 318 ms). Common, not a warning sign
• 350 ms: about the Scottish keypad mean at ages 56 to 69 (354 to 358 ms). Check the device first: some TVs add up to 150 ms and phone taps are slower than clicks

Does reaction time correlate with IQ?

Yes, modestly. Deary, Der and Ford (2001) tested 900 people, all about 56, and correlated reaction time with the Alice Heim 4 intelligence test: r = -.31 for simple reaction time and -.49 for four-choice. The sign is negative because shorter times go with higher scores. Der and Deary (2017) reported 2,196 people at ages 30, 50 and 69 (714, 813 and 669 people): simple reaction time correlated -.27, -.30 and -.32 with the same test, and four-choice -.44, -.47 and -.53. Squaring a correlation gives the share of variance the two measures have in common, which is 7% to 10% for simple reaction time and 19% to 28% for four-choice.

Mixing ages inflates the figure. Pooled across the three age groups the correlations were -.36 for simple and -.58 for four-choice reaction time; with age held constant they fell to -.30 and -.49. Sheppard and Vernon's 2008 review found a summary correlation between overall reaction time and g of -.26 across 112 samples, ranging from -.22 for simple reaction time to -.4 for eight-choice, as Der and Deary report it. The g factor is the general ability these studies are measuring against.

In IQ points, a correlation of -.3 means that a person whose simple reaction time is one standard deviation quicker than average is expected to score about 4.5 points above 100 (0.3 times 15), with individual scores still spread by about 14 points around that expectation. At -.49, one standard deviation quicker on four-choice reaction time is worth about 7 points. Our percentile calculator and guide to IQ z-scores show how a standard-deviation gap maps to a percentile. One caveat runs through these studies: the Alice Heim 4 is a time-limited test, as Der and Deary note, so part of the correlation is speed on both sides.

Why an online reaction test cannot estimate your IQ

There are three reasons. First, the correlation is too small: at 7% to 10% of variance, simple reaction time leaves about 90% of the difference in IQ unexplained. Second, the measurement is too noisy: Human Benchmark's own page says your computer could add 10 to 50 ms, and at the 0.55 ms per year slope in Woods and colleagues' data that is the size of 18 to 91 years of ageing, so device differences swamp person differences. Third, a single click test is one trial, while the studies above used calibrated equipment and many trials.

Does mental speed really fall after age 20?

Reaction times do lengthen from the twenties, but a 2022 study in Nature Human Behaviour suggests that is not the same as thinking more slowly. Von Krause, Radev and Voss fitted a decision model to response-time data from more than a million people and reported that processing speed was stable from young adulthood until about age 60. In the preprint abstract they attribute the slower average responses over that span to more decision caution and slower encoding and motor response, not to a drop in cognitive processing speed. That fits Woods and colleagues' finding that detection time stayed near 131 ms at every age while motor output slowed. Our research page on the age at which each skill peaks shows the same kind of age curves for other abilities.

Were the Victorians faster, and so cleverer?

Francis Galton recorded visual simple reaction times of 181 to 189 ms in people aged 18 to 60, as Woods and colleagues summarise it, citing Johnson (1985). Woodley, te Nijenhuis and Murphy (2013) argued from reaction-time studies that slower modern times reflect a decline in processing speed, and so in general intelligence since Victorian times.

The argument was disputed at once. Dodonova and Dodonov (2013) argued that Galton recorded the shortest of three trials per person, which would make his figures faster than a mean. Woods and colleagues tested contemporary samples on calibrated equipment and found no evidence of slowed processing speed. Woodley and colleagues replied in 2015 that, even accepting the best-of-three correction for Galton, which lifts his figure to 208.5 ms for 3,418 people, UK means rose to 237.8 ms in Deary and Der's 2005 study of 543 people, after subtracting an allowance for LCD screen lag and key-press time (the raw figure was 300.8 ms), about 22.8 ms slower per century, and maintained that the evidence for generational slowing remains quite compelling. Human Benchmark says its own recorded times have slowed slightly and attributes this almost certainly to changes in input and display technology. The question is unresolved, and it sits alongside the debate over whether raw IQ scores are still rising, covered in our guide to why IQ norms expire.

What is the fastest a human can react?

Sport supplies a rule, not a biological limit. World Athletics technical rules say the start information system indicates a possible false start when the reaction time is less than 0.100 second. The rule is for officials, not a measurement of the limit of human speed, and the text we read does not say why 100 ms was chosen. In the laboratory, the quickest part of the chain is detection: Woods and colleagues measured about 131 ms for detecting a stimulus, before any movement. A choice-reaction task with a conflict twist is explained in our guide to the Stroop test.

Reaction time is one thread of processing speed, and processing speed is one of several abilities a full test samples. Vocabulary, for instance, keeps growing long after speed has peaked, as our guide to how many words the average person knows shows, and our guide to WAIS index scores shows how a Processing Speed Index is reported. For a timed test on the standard scale, try the timed IQ test or the full IQ Metrics test.

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