Fluid Intelligence vs. Crystallized Intelligence

Fluid Intelligence vs Crystallized Intelligence

Illustration by Emily Roberts, Verywell

When you think about intelligence, what sort of things comes to mind? Intelligence is more than simply the accumulation of facts. It also encompasses the ability to learn new things as well.

So when you think of intelligence, you might think of having a lot of knowledge about different subjects. But you also might consider quick thinking and the ability to reason. Such factors represent what psychologists refer to as crystallized intelligence and fluid intelligence.

So what exactly are these two aspects of intelligence and how do they differ? Fluid intelligence refers to the ability to reason and think flexibly. Crystallized intelligence refers to the accumulation of knowledge, facts, and skills that are acquired throughout life.

People often claim that their intelligence seems to decline as they age. However, research suggests that while fluid intelligence begins to decrease after adolescence, crystallized intelligence continues to increase throughout adulthood.

Psychologist Raymond Cattell first proposed the concepts of fluid and crystallized intelligence and further developed the theory with his student John Horn. The Cattell-Horn theory of fluid and crystallized intelligence suggests that intelligence is composed of different abilities that interact and work together to produce overall individual intelligence.

Fluid Intelligence

Cattell defined fluid intelligence as "…the ability to perceive relationships independent of previous specific practice or instruction concerning those relationships."

Fluid intelligence is often defined as:

  • A global capacity to reason
  • The ability to learn new things
  • The capacity to reason

Fluid intelligence involves being able to think and reason abstractly and solve problems. This ability is considered independent of learning, experience, and education. Examples of the use of fluid intelligence include solving puzzles and coming up with problem-solving strategies.

This aspect of intelligence involves the ability to solve problems and reason about things independent of previously existing knowledge. When you encounter an entirely new problem that cannot be solved with your existing knowledge, you must rely on fluid intelligence to solve it.

Fluid intelligence tends to decline during late adulthood. Certain cognitive skills associated with fluid intelligence tend to decline as people reach later adulthood.

Crystallized Intelligence

Crystallized intelligence involves knowledge that comes from prior learning and past experiences. Situations that require crystallized intelligence include reading comprehension and vocabulary exams.

This type of intelligence is based upon facts and rooted in experiences. As we age and accumulate new knowledge and understanding, crystallized intelligence becomes stronger.

As you might expect, this type of intelligence tends to increase with age. The more learning and experience you have, the more you build up your crystallized intelligence.

Fluid vs Crystallized Intelligence

Does one of these factors tend to be more important? Both factors of intelligence are equally important in everyday life. For example, when taking a psychology exam, you might need to rely of fluid intelligence to come up with a strategy to solve a statistics problem, while you must also employ crystallized intelligence to recall the exact formulas you need to use.

Fluid intelligence along with its counterpart, crystallized intelligence, are both factors of what Cattell referred to as general intelligence. While fluid intelligence involves our current ability to reason and deal with complex information around us, crystallized intelligence involves learning, knowledge, and skills that are acquired over a lifetime.

Despite the name, crystallized intelligence is not a form of fluid intelligence that has become 'crystallized.' Instead, the two factors of general intelligence are considered separate and distinct.

However, fluid and crystallized intelligence are intertwined. Crystallized intelligence is formed through the investment of fluid intelligence when information is learned. By using fluid intelligence to reason and think about problems, the information can then be transferred to long-term memory so that it can become part of crystallized intelligence.

Fluid and Crystallized Intelligence Throughout Life

Fluid and crystallized intelligence tend to change throughout life, with certain mental abilities peaking at different points. Fluid intelligence has long been believed to peak quite early in life, but some new research suggests that some aspects of fluid intelligence may peak as late as age 40. Crystallized intelligence does tend to peak later in life, hitting its apex around age 60 or 70.

Some things to remember about fluid and crystallized intelligence:

  • Both types of intelligence increase throughout childhood and adolescence
  • Many aspects of fluid intelligence peak in adolescence and begin to decline progressively beginning around age 30 or 40
  • Crystallized intelligence continues to grow throughout adulthood

Improving Crystallized and Fluid Intelligence

Crystallized intelligence is clearly something that can be improved through learning. The more accumulated knowledge you have, the more crystallized intelligence you will possess. So if you are interested in improving this aspect of intelligence, furthering your education either formally or informally is something that will help.

Until fairly recently, fluid intelligence has largely been something that was believed to be set in stone. Recent research also suggests that brain training might play a role in improving certain aspects of fluid intelligence.

Previous research on intelligence suggested that people really didn't have much control over their intelligence at all. Instead, it was believed that our IQ was largely determined by genetics and that training programs aimed at increasingly IQ tended to have limited effectiveness.

A more recent study found, however, that it is possible to improve fluid intelligence with brain training that focuses on working memory. Where long-term memory is focused on storing facts and information over long periods of time, working memory is a form of short-term memory centered on what you are currently thinking about. This type of memory involves not only being able to store information for a brief period of time, but also the ability to mentally manipulate that information.

It makes sense that training participants on a working memory task would improve their performance on that specific task. What the researchers discovered, however, was that such training also increased abilities on completely unrelated cognitive ability tasks.

Recent research on the ability to increase fluid intelligence by improving working memory has a number of important implications.

  • Fluid intelligence can be trained
  • The more you train, the better your results
  • Skills are transferable to other domains; training in one area of working memory resulted in gains in other cognitive skills that were unrelated to the training tasks

A Word From Verywell

The participants in the research mentioned previously were engaged in an intensive and difficult brain training task over a relatively short period of time. This doesn't mean that you can't enjoy similar improvements in your own life.

So what are some things you can do to improve your own fluid intelligence?

Seek out new challenges. Gains in intelligence don't come from sticking to the same old routines. Keep exploring new things in life and keep learning new things. Tackle learning a new language. Take piano lessons. Visit a new country and learn about the people and culture. All these types of activities keep your brain engage, challenged, and focused on learning new things in new ways.

Seeking new knowledge helps build your crystallized intelligence over time, but challenging yourself may also bring important improvements to your fluid intelligence as well.

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Article Sources
  • Horn, J. L., & Cattell, R. B. (1967). Age differences in fluid and crystallized intelligence. Acta Psychologica, 26, 107-129.
  • Jaeggi, SM, Buschkuehl, M, Jonides, J, & Perrig, WJ. Improving fluid intelligence with training on working memory. Proceedings of the National Academy of the Sciences. 2008;105(19;6829-6833. doi:10.1073/pnas.0801268105.