20 articles

IQ, explained plainly

The questions people actually type into search boxes, answered without mystique. Where there is good evidence we say so. Where the honest answer is “nobody really knows”, we say that instead.

Start here20 articlesWhat is a good IQ score?Anything above 115 is above average. 130 is where gifted usually starts. The harder question is what you want the number to do for you, because for most purposes the answer is not much.Read it

What is the average IQ?

The average IQ is 100. That is not a finding, it is a definition. Every major test is deliberately calibrated so the middle of the population lands on exactly that number.

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What does IQ stand for?

IQ stands for intelligence quotient. The quotient part is a fossil: it describes a piece of arithmetic that intelligence tests stopped doing nearly a hundred years ago.

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How to increase your IQ

If you have decided to try, here is the practical version: what has evidence behind it, what only looks like it does, and what is worth doing regardless of whether it moves a number.

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IQ test scams and how to spot them

You answer questions for forty minutes, a progress bar crawls to 100 percent, and then it asks for your email. That is not a broken free test. That is the product working exactly as designed.

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How is IQ measured?

Not by counting correct answers. Your raw performance is compared against a reference population, then converted onto a scale fixed at 100. That middle step is what separates a test from a quiz.

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IQ percentiles explained

A percentile is the share of people you scored above. It is more useful than the IQ number itself, because it tells you where you sit rather than handing you an abstraction.

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The Flynn effect

Through most of the twentieth century, raw performance on IQ tests climbed by roughly three points per decade. The reported average never moved, because tests are quietly re-normed to keep it at 100.

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Fluid vs crystallized intelligence

One is your ability to reason through a problem you have never seen. The other is everything you have accumulated. They are measured differently, they peak at different times, and conflating them causes most of the confusion about IQ and ageing.

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Can you increase your IQ?

Somewhat. Education has a real, measured causal effect. Almost everything marketed as IQ improvement does not, and the gap between those two facts is where the entire industry lives.

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The WAIS test

When people talk about a real IQ test, this is usually what they mean. The Wechsler Adult Intelligence Scale is administered one to one by a psychologist, takes over an hour, and produces far more than a single number.

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Raven's Progressive Matrices

A grid of abstract shapes with one piece missing. No words, no arithmetic, nothing to have studied. It is the purest widely used measure of fluid reasoning, and the benchmark most other tests are validated against.

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The Stanford-Binet test

The oldest IQ test still in use, and the source of nearly every implausible historical score you have read. Its history explains why numbers like 228 exist and why they do not mean what they appear to.

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What IQ do you need for Mensa?

Mensa accepts the top 2 percent. On a standard scale that line falls around 132, but the qualifying number differs by test, and nothing you take at home counts.

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Are online IQ tests accurate?

Some are genuinely useful. Most are not. The thing that separates them is not how hard the questions look, and it is not something most sites will tell you.

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Does IQ change with age?

Your position relative to your age group is fairly stable. The abilities underneath it are not: some peak in your twenties, others keep climbing into your sixties.

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Is IQ genetic?

Partly. But heritability is one of the most misread statistics in science, and almost every strong claim made in its name, in either direction, gets the concept wrong.

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Does IQ predict success?

It predicts some things moderately, most things weakly, and almost nothing on its own. The interesting part is not the correlation. It is where the correlation stops working.

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IQ vs EQ

One is a century-old measurement with well-understood limits. The other is a younger, looser construct that got very popular very fast. The contest is less even than it is usually sold as, in both directions.

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What is the highest IQ ever recorded?

The highest widely cited figure is 228, recorded for Marilyn vos Savant. Here are the real claimants and their numbers, followed by the reason none of them can be ranked against each other.

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