Fluid vs crystallized intelligence

fluid vs crystallized intelligence
Learning about fluid vs. crystallized intelligence

Fluid vs crystallized intelligence. What’s the difference? General intelligence can be decomposed into (1) crystallized and (2) fluid intelligence. Fluid vs crystallized intelligence are simple concepts to grasp. Crystallized IQ relates to general knowledge and verbal ability, which is accumulated over time in formal education. Crystallized IQ test questions may include grouping synonyms, explaining the meaning of words, identifying antonyms, working with analogies or perhaps even filling in the blanks in a paragraph with missing words.

Fluid intelligence, on the other hand, relates to one’s ability to solve novel problems. The latter type of intelligence cannot emanate from materials taught in schools. Fluid IQ test questions may include identifying patterns, finding a missing sequence and spatially manipulating complex figures. So when I test my IQ, it is quite possible to expect different levels of performance on crystallized vs fluid intelligence components of the test.  That said, the two measures should be correlated, but more in one direction that the other.

Fluid vs crystallized intelligence: the correlation

Research on intelligence has shown that individuals with a strong fluid intelligence are more likely to also have strong crystallized intelligence rather than the other way around. The reason being that fluid intelligence is largely innate and peaks in our mid 20s, only to beging a gradual decline thereafter. Someone who has strong fluid intelligence and is able to make sense of the world they live in, and will possess an uncanny ability to solve novel problem around them.  On average, these individuals are more likely to be able to breeze through education with ease and therefore to accumulate a greater body of knowledge than someone who struggles to see the logic in academic materials. For this reason, high fluid intelligence is strongly positively associated with crystallized IQ.

But this is not to say that all individuals with a Masters degree or a PhD will have a high fluid IQ. Some Individuals with low to moderate fluid intelligence may well be extremely motivated and hard-working which means that they may be able to succeed at obtaining higher degrees, which may lead to a reasonably high crystallized IQ result, despite having an average level of fluid intelligence. There really is no substitute for hard work and motivation.

So in simplistic terms, this explains the interrelationship between fluid vs crystallized intelligence.  At, we believe that fluid intelligence is a better measure of the raw processing power of the human brain and is better suited to a global internet audience with differing levels of education. That is, our fluid IQ tests do not confer any form of advantage to people with higher levels of education.

Fluid vs crystallized intelligence are easy enough concepts to explain. But testing these components individually are clearly subject to measurement error.

At, we aim to provide the most accurate IQ fluid intelligence testing on the Web. More specifically, we have created a series of tests which aim to replicate the level of difficult and time pressures that would be associated with a proctor-administered tests or those administered by high IQ societies such as Mensa.

To take our IQ tests online, click here.