My girlfreind is currently doing a doctorate psychology study, of which a small part is a standardised IQ test (though I dont know which standard; there are several). She asked if she could practice the process on me.
There are several sections, but to pick 2.
For language acuity, I scored OK. This section basically asked you to define a series of given words. Your knowledge here absolutely would change depending on your environment, job and education.
For pattern recognition, I scored fantastically. But I know this is because of years of studying geometry in math classes. I know exactly what my thought processes were, "Count the vertexs, count the edges, count the bisections, are some things odd, are some things even, do some things add together, do the shapes mirror once/twice, are they rotated". I know exactly where I picked those ideas up.
In the UK you can drop Maths and English/Creative Writing at 17. If you finish a pHD at 26 you havent regularly explored those ideas in near on 10 years, but you absolutely could still achieve it, so I do think its a better measure.