Eminent scientist and intelligence blogger Bruce Charlton once blogged about converting reaction times into IQ score equivalents, and now that blogger alcoholicwisdom has told this blog about a really user friendly reaction time test at humanbenchmark.com, it’s time to explore this idea further.


The average reaction time of those who take that test is 253 ms. In order to equate that to IQ, we need to know the average IQ of people who take that test. Well we can estimate the average IQ to be 117 because many years ago, a company called Braintainment sold a complex series of reaction time tests called “Thinkfast” and customers on their website had an average IQ of 117 based on a five-minute IQ test. Even though Thinkfast customers are not the same as humanbenchmark.com visitors, it’s reasonable to assume that both populations have the same IQ, since they’re both self-selected internet users with an interest in reaction time.

Thus 253 ms = 117 IQ

Some might argue that you can’t just equate the two figures because there’s no reason to assume chronometric players will be equally self-selected for reaction time as they are for IQ. But what they’re really self-selected for is intellectual interests and the internet access to pursue them. Since this self-selection is g loaded, and since both reaction time and a 5 minute IQ test are probably both only moderately g loaded, it seems reasonable to equate them. In fact, this is a well known psychometric technique called equipercentile equating, and was used to norm the famous Mega test using SAT scores (see section 8.4.1 of the Prometheus MC Report for more details).

The next thing we need to do is equate the standard deviation for simple reaction time with the standard deviation for IQ. Scholar Michael Woodley and his colleagues have argued that the population standard deviation for simple reaction time in Western countries is 160.4 ms, a truly colossal figure. However scholar Arthur Jensen has shown that when you measure the mean reaction time repeatedly in college students (each one playing 20 times and taking the average simple reaction time for each student), most of the variability between individuals gets cancelled out and the standard deviation of the averaged out reaction times is only 29.23. The standard deviation for IQ in the general U.S. population is 15.

Thus, when taking your average reaction time from 20 tries:

29.23 ms = 15 IQ points

Some people might object that college students have a restricted range of reaction times because they’re selected for general intelligence. However because the correlation between reaction time and education is weak, and because even among college students, there is enormous range in education (some drop out their first year, others go on to get PhDs) it’s likely that college students are not a chronometrically range restricted population.

It should be noted that Bruce Charlton believes one’s best reaction time scores are more meaningful than one’s average scores, however we do not have stats for best performance, so average performance will have to do for now.

So now that we have these two data points, we can convert reaction time to the IQ scale.


Step 1: Make sure you are on a desktop or laptop computer with a clickable mouse (mobile devices give much slower reaction times)

Step 2: Go to humanbenchmark.com’s reaction time test

Step 3: Play 8 warm-up tries to get practice. When you reach “Trie: 5 of 5”, it will ask you if you want to save your scores. Just ignore that question and keep playing until you reach “Trie: 8 of 5” (your 8th warm-up). You will notice your average reaction time being calculated on the screen. Ignore this because you are just doing warm-ups so your scores don’t count.

Step 4: Revisit the humanbenchmark.com reaction time test on a fresh screen so that you can get a new running average. Now play 20 consecutive tries and record the average reaction time it calculates from all 20 tries. This will be your score.

Step 5: Go to the poll below to record your reaction time and observe the IQ equivalent. Don’t be depressed if your reaction time is terrible. Simple reaction time is just a crude physiological proxy for intelligence, much like brain size so I expect brilliant people to regress enormously to the mean and for many gifted people to have slow reaction times. Just as there were Geniuses like Einstein who had small brains, there will be Geniuses who have slow reaction times. Also, reaction time slows precipitously with age. If you’re older than the average person who visits humanbenchmark.com, your IQ equivalent will be further depressed (severely so).

NOTE: The IQ conversions I discuss are just my own personal conjecture and have not been endorsed by humanbenchmark.com (a website I have no connection to)