Psychologists split general intelligence into two big parts. Knowing which is which explains why a quiz champion and a puzzle master can both be "smart" in very different ways.
Fluid intelligence
This is your ability to reason about something new: spotting a pattern, working out a rule, solving a problem you have never met. Matrix puzzles, number series and logic grids test it, because no prior knowledge helps. Fluid intelligence tends to peak in early adulthood and then drift down slowly.
Crystallized intelligence
This is accumulated knowledge and skill: vocabulary, facts, expertise, know-how. It grows with experience and often keeps rising into the sixties or beyond. A doctor reading an X-ray or a lawyer spotting a loophole is using crystallized intelligence.
How they work together
Fluid intelligence is how fast you learn; crystallized intelligence is how much you have learned. Strong fluid reasoning builds knowledge quicker, and deep knowledge lets you solve familiar problems almost without thinking. Over a lifetime, experience can offset a slower fluid engine.
Growing each one
- Fluid: do unfamiliar puzzles, learn new skills, switch between topics, practise with pen and paper.
- Crystallized: read widely, study deeply, teach what you learn, keep a few areas you go really deep in.
Good IQ tests, including the Real IQ Test, lean on fluid reasoning and working memory so that your score does not depend on what school you attended. To train that side, try Today's Enigma and the Puzzle Vault.