How is Fluid Intelligence Different from Crystallized Intelligence

The first time the terms fluid intelligence and crystallized intelligence are mentioned, it feels like the world is challenging your intelligence and calling you adamant and unaccommodating! But once you gather what it means, you are all ears! Psychology is really such an interesting subject.

Fluid intelligence and crystallized intelligence were coined by Raymond Cattell - a renowned psychologist known for his significant contributions to understanding human intelligence and his famous 16PF Questionnaire.
Even prior to Cattell, the idea of there being two different kinds of intelligences was making its rounds in the psychology fraternity.

Charles Spearman was the first one to have developed the theory of general intelligence (g). He theorized general intelligence and then segregated it into two basic types, viz. educative and reproductive. This is what laid the foundations for the concepts of fluid intelligence (Gf) and crystallized intelligence (Gc).

Basic understanding and comprehension skills is what comes under fluid intelligence. Fluid intelligence is like your means to understand your world. It encompasses learning abilities, logic, problem-solving abilities, pattern recognition and the likes.

Fluid intelligence is hence, independent of any knowledge or information we may have gathered prior to a particular instance of the application of fluid intelligence. It does not 'increase' or 'decrease' with age per se, because it talks more about our abilities and abilities cannot be quantified.

However, according to a study conducted by Susanne M. Jaeggi, fluid intelligence can be improved through training (the original research paper can be found on the Proceedings of the National Academy of Sciences website). It is said that fluid intelligence is at its peak in young age but declines steadily with age.

Crystallized intelligence deals with acquired knowledge which we can recall and reuse at a later point of time. The acquisition and expansion of crystallized knowledge thus, depends on fluid intelligence. It is that which one acquires through experience of the world around us. Reasoning ability is also a part of our crystallized intelligence.

Education, experience, environment, all contribute to it; but they CAN contribute because of our ability to comprehend these things, or - in other words - our fluid intelligence. Crystallized intelligence can hence be quantitatively increased.

By the time man had begun to inquire about 'human intelligence' and what it exactly means, what is its nature, etc., the idea of there being multiple intelligences had already held ground. Different kinds of things need different abilities, and our general intelligence is equipped with all the necessary devices to deal with it.

Fluid intelligence (Gf) is like the software of a phone, for example. The software is what enables different applications to run smoothly on the phone. Crystallized intelligence, on the other hand, are the applications themselves. You can acquire innumerable number of applications on your phone.

However, if the software of your phone does not support a particular application, it won't be able to run the application! Fortunately, it is not so crude for humans. The amount of crystallized intelligence a person acquires does depend on his/her fluid intelligence, but we are not altogether at the mercy of this intelligence!

Different parts of the brain - or rather, different brain-systems - are responsible for fluid and crystallized intelligence. Fluid intelligence involves all the systems related to short-term memory - one of them is the dorsolateral prefrontal cortex. On the other hand, crystallized intelligence is dealt with by brain systems involved in long-term memory.

It is believed that the fluid intelligence of an individual is affected in diseases such as Autism spectrum disorders (ASD), Autism spectrum conditions (ASC), and even Asperger syndrome, etc. This could probably answer why such people are still exceptionally gifted in doing certain things or tasks that are governed by acquired crystallized intelligence.

There are several tests that have been devised by leading psychologists to 'measure' these two types of intelligence that every human being possesses. A couple of the most common tests to measure fluid intelligence is the RPM - Raven Progressive Matrices, and the Cattell Culture Fair IQ Test.

Even apart from medical reasons, these tests are fun to take - maybe you could take one yourself. Chances are you will do well. But if you don't, don't be bogged down! You are probably just tired! Look forward to solving your doubts and keep exploring!