What’s the fluid intelligence definition in psychology?

In this brief guide we are going to we will give you the definition of fluid intelligence according to psychology, we will explain what it is, and how to improve it.

What’s the fluid intelligence definition in psychology?

Fluid intelligence refers to the person’s capacity to adapt and face new situations in an agile way, without previous learning, experience or acquired knowledge being a determining factor in its manifestation.

Along with beauty, we privilege intelligence. Intelligence to know how to develop ourselves, to acquire knowledge and skills, succeed, and to try to overcome neurodegenerative diseases.

And in this sublimation of intellect, a question echoes over and over again: is intelligence born or acquired? Genetics versus environment, is a debate in which, in recent years, DNA has been losing points to the environment in which we grow up. Genes are the basis on which the impressions that the social framework leaves on us are accommodated.

There are many forms of intelligence, but basically two types can be distinguished: fluid intelligence and crystallized intelligence.

Intelligence is defined as the mental capacity that allows us to reason, understand, solve problems, use abstract thinking and learn, among other processes.

But how many types of intelligence are there? Some say there are many types of intelligence, from emotional intelligence which facilitates our ability to empathize and relate to others, to others that are much more technical.

Others say that there’s just one type of intelligence. However, here we are going to focus on fluid intelligence.

What is fluid intelligence?

Raymond Cattell, an important figure in the history of British psychology, was the first to develop a theory of intelligence in which he introduced the concept of fluid intelligence (Gf).

For Cattell, this type of intelligence deals with the mental processes that we carry out to solve new problems, without having previous notions about them. This intelligence is under the effects of maturational processes, so it decreases as we age.

Fluid intelligence is at its peak during the early stages of human development. Before reaching adolescence, young people solve most situations using primary aptitudes. We are referring to the capacity for induction, deduction, figurative classifications, among others.

This kind of intelligence diminishes as the years go by. It is logical to think that one does not have the same flexibility of thought at 60 years of age than at 11 years of age.

To measure fluid intelligence there are several tests that are responsible for determining the biological capacity of people to continue learning. In other words, these instruments measure the brain’s potential to acquire new knowledge.

Fluid intelligence includes deductive and inductive reasoning processes, which gives us the ability to solve all kinds of problems. Specifically, thanks to this intelligence we can carry out the analysis of simple or complex daily tasks, and we are able to extrapolate knowledge.

That is, it allows us to use logical reasoning, identifying and relate concepts, ideas and knowledge.

Fluid intelligence versus crystallized intelligence

Crystallized intelligence (CQ) was another of the concepts contributed by Cattell in his theories. Contrary to fluid intelligence, crystallized intelligence is the one that allows us to solve conflicts by means of already acquired knowledge. This type of intelligence is influenced by education, culture and our experiences. And it is closely related to language.

In fact, both types of intelligence are related and have a high correlation index. So they are not independent of each other, quite the contrary. In fact, it has been discovered that the individual differences that we present with other people in our level of crystallized intelligence are determined by fluid intelligence.

We can affirm that Gf is superior to crystallized intelligence, but the latter has the advantage of increasing with age, while the opposite is true for fluid intelligence. This explains the higher cognitive performance of young people compared to the elderly.

Another important fact is that crystallized intelligence is more sensitive to change, that is, when we learn new things our knowledge changes and increases. And therefore this type of intelligence grows, but likewise if a person does not acquire knowledge it will not increase.

On the other hand, fluid intelligence is much more affected by possible brain injuries, given the reasoning processes involved in it. In short, our brain makes joint use of both, thus increasing our cognitive capacity and improving our resources.

Keep learning

Fluid intelligence is understood as basic intelligence, from birth. Crystallized intelligence is the result of learning and experience. They are not mutually exclusive. Everyone is born with certain fluid intelligence, but this does not imply any ceiling or limit.

A person who is born and grows up in a stimulating environment will improve his crystallized intelligence. And another who, with the same fluid intelligence, develops in an environment lacking incentives will be left behind.

However, anyone can improve their mental functions through learning and cognitive training, since thanks to brain plasticity mechanisms, modifications in the structure and functioning of the nervous system can be produced, both in healthy subjects and in those who have suffered brain damage.

The brain is one of the most studied organs in recent years. Thus, neurobiology has shown that we continue to create neurons and connections between them with age, that we learn by imitation thanks to mirror neurons and that intelligence can be made to grow.

Until a few decades ago, it was believed that fluid intelligence, the innate intelligence, grew until the age of 18. Crystallized intelligence has no expiration date. The more you learn, the more intelligence you acquire”.

Today the market offers a range of products to stimulate intelligence, the so-called cognitive stimulants, smart drugs or nootropics. Pills that ensure better concentration, creativity, memory and intelligence are associated with better performance.

Stimulating intelligence

The intellectual gymnasium is obtained with the study and practice of languages (“three better than two”), mental crunches in the form of exercises aimed at the intellect, sports, happiness, a healthy and balanced diet and, above all, music.

It has been seen that the brains of people who study music are different. They have a more developed corpus callosum, the set of nerve fibers that connect the two hemispheres of the brain. As a result, they are better able to solve problems using both brain areas.

Learning is the stimulus for crystallized intelligence, but can fluid, innate intelligence be exercised? Yes, it can. And the recipe is the same, learning because crystallized intelligence influences fluid intelligence.

When we learn, two things happen in the brain: on the one hand, brain circuits improve and new ones are generated. On the other hand, intelligence forces the brain to create new connections.

As with nutrition and sports, intelligence depends on constant training. No miracle formulas, but a little perseverance to ensure a full life.


Intelligence, the engine of human capabilities, is the most powerful technique of all. To take advantage of it, we must know the specific expressions over which the mind has a monopoly; among others, problem-solving and the coordination required for social interaction. We far surpass machines, which operate through logical routines. 

The intellect makes sense of complex information and harnesses that information to solve problems. It can detect patterns and pathways that elude the most advanced computers. In coordinating work that requires social interaction, smooth communication must be combined with the emotional tone of interactions. Effective work must take into account the myriad ways in which people differ (personality, interests, character, experience, etc.).

It is clear that human intelligence presents a wide range of manifestations; among them, the author highlights fluid intelligence and crystallized intelligence. The former refers to the mind’s capacity to adapt to a novel, complex and changing environment.

A person is said to be intelligent if he or she is able to cope well with new situations, novel tasks or embarrassing problems. Crystallized intelligence is manifested in the ability to master large bodies of information. It is usually associated with a verbal capacity. Fluid and crystallized intelligence complement each other.

Crystallized intelligence offers current knowledge, what is already known. But if the acquired knowledge is not enough, the void is filled by fluid intelligence, the ability to deal with the unknown.

We can delimit fluid intelligence in multiple ways. Some tests of fluid intelligence use abstract forms, while others use words or numbers. All share a common trait: tests of fluid intelligence require the subject to perceive a complex pattern and apply it to the solution of a problem.

Novelty is also an aspect to be considered. It is important that the problem or puzzle be presented to the subject for the first time. This requirement of novelty is the distinguishing feature of Raven’s matrices, a classic test of fluid intelligence.

Crystallized intelligence constitutes the intellectual resource that corresponds to structural knowledge, together with learning skills that facilitate the construction of knowledge over time.


Colom, R., Rubio, V. J., Shih, P. C., & Santacreu, J. (2006). Fluid intelligence, working memory and executive functioning. Psicothema, 816-821.

Yuan, K., Steedle, J., Shavelson, R., Alonzo, A., & Oppezzo, M. (2006). Working memory, fluid intelligence, and science learning. Educational Research Review, 1(2), 83-98.