What do IQ Tests Test?

If you think IQ tests test intelligence, you might ask yourself: How do you know?

What is intelligence?

Give us your definition.

Or by intelligence do you just mean IQ, in which case your understanding of intelligence is tautological: intelligence is performance on an IQ test, which is measured by performance on an IQ test.

IQ and wealth at low scale (outside the tail).
Mostly Noise and no strikingly visible effect
above $40K, but huge noise. Psychologists
responding to this piece do not realize that
statistics is about not interpreting noise.
From Zagorsky (2007) via Nassim Taleb.

Fact is, the IQ testers never have defined intelligence. Instead, they came up with a set of puzzlers and declared your score on this test is the measure of your intelligence.

Trouble is, the IQ-ists have never attempted to show how IQ test results relate to what is understood by the term intelligence as manifest by, say, the creative work of a poet, a painter, a composer, an architect, or a scientist, or the more mundane endeavors of a politician, a policeman, a prostitute or a peddler of illicit drugs. Their strongest claim is that IQ tests predict "career success", except as anyone who looks into the matter will find, the correlation is trivial.

The best that IQ tests can do is provide an indication of academic aptitude, but even in that case they don't work well, not even as well as traditional academic exams, which is why Harvard and other such places use a SAT test with a mathematical component and a verbal component, the results of which are by no means closely correlated

Better still, obviously, would be to break things down further, e.g., SAT Physics, SAT Biology, SAT English, SAT music, etc. Except that would be giving up, since it would be an acknowledgement that the whole idea of intelligence as unitary feature of mind measurable on a single linear scale is nonsense.

Related:
Nassim Taleb: The psychologists' construct, general intelligence, is based on a statistical error.