Fluid vs. Crystallized Intelligence

Fluid vs. crystallized intelligence is one of many theories of intelligence in psychology. Fluid intelligence involves the ability to reason and think flexibly, whereas crystallized intelligence refers to the accumulation of knowledge, facts, and skills that are acquired throughout life.

The theory of fluid vs. crystallized intelligence was first proposed by psychologist Raymond Cattell; he further developed it along with his student John Horn. The theory suggests that intelligence is composed of different abilities that interact and work together to produce overall individual intelligence.

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.

Fluid Intelligence vs Crystallized Intelligence
Verywell / Emily Roberts

Fluid Intelligence

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

What Is Fluid Intelligence?

Fluid intelligence involves being able to think and reason abstractly and solve problems. This ability is considered independent of learning, experience, and education.

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 examples include:

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

Crystallized Intelligence

Crystallized intelligence involves knowledge that comes from prior learning and past experiences.

What Is Crystallized Intelligence?

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

Crystallized intelligence examples include:

  • Memorizing text
  • Memorizing vocabulary
  • Recalling how to do something
  • Remembering dates and locations

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.

Differences Between Fluid and Crystallized Intelligence

There are several ways in which each intelligence type is distinct.

Fluid Intelligence
  • Refers to current ability

  • Involves openness to learning new things

  • Decreases with age

Crystallized Intelligence
  • Refers to prior learning

  • Involves recalling specific facts

  • Increases with age

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 its name, crystallized intelligence is not a form of fluid intelligence that has become "crystallized." Instead, the two facets of general intelligence are considered separate and distinct.

Changes in Fluid vs. Crystallized Intelligence

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 research published in 2015 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.
  • Crystallized intelligence continues to grow throughout adulthood.
  • Many aspects of fluid intelligence peak in adolescence and begin to decline progressively beginning around age 30 or 40.

Fluid and Crystallized Intelligence Tests

It's thought that standard IQ tests don't entirely capture a person's fluid and crystallized intelligence levels. So, what tests can measure these intelligence types?

Tests that measure fluid intelligence:

  • Raven's Progressive Matrices Test (RPM) is a non-verbal assessment that asks a person to examine various shapes and pick from a choice of shapes to complete a pattern.
  • Woodcock-Johnson Test of Cognitive Abilities measures cognitive skill and achievement; it's often given to children to assess them for advanced academic courses.
  • Wechsler Intelligence Scale for Children measures verbal, reasoning, and memory skills. It is primarily administered to children between the age of six and 16.

Tests that measure crystallized intelligence:

  • Vocabulary and general knowledge tests
  • Wechsler Adult Intelligence Scale (WAIS) is a measure of cognitive abilities developed for adults. It provides separate scores for different areas as opposed to an overall intelligence score.

Improving Fluid and Crystallized Intelligence

Past 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 increasing IQ tended to have limited effectiveness.

By contrast, an analysis of previous studies published in 2014 found that it is possible to improve fluid intelligence with brain training.

What the researchers discovered, however, was that the training also increased unrelated cognitive skills, including the ability to reason and solve new problems totally independent of previously acquired knowledge.

In essence, with training, a person may be able to engage the abstraction of thoughts and ideas as readily as applying knowledge-based reasoning.

How to Improve Fluid Intelligence

  • Challenge yourself
  • Mix up your routine
  • Think creatively
  • Socialize on a regular basis

Crystallized intelligence, on the other hand, is something that can be improved through learning. The more accumulated knowledge you have, the more crystallized intelligence you will possess.

How to Improve Crystallized Intelligence

  • Learn a new language
  • Learn a new skill
  • Take a class
  • Read books

Seeking new knowledge helps build your crystallized intelligence over time, but challenging yourself with new experiences can improve your fluid intelligence as well.

How Fluid and Crystallized Intelligence Work Together

Does one of these intelligence types tend to be more important?

Both types of intelligence are equally important in everyday life. For example, when taking a psychology exam, you might need to rely on 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.

Though each is a distinct type of intelligence, 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.

A Word From Verywell

Study participants usually engage in intensive and difficult brain training tasks over relatively short periods of time. This doesn't mean the same techniques can't be applied to your own life. The principles are the same.

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 of these types of activities keep your brain engaged, challenged, and focused on learning new things in new ways.

18 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Kendra Cherry
Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology.