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The Fluid vs. Crystallized Intelligence Theory Explained

What is it?

One of the ideas of intelligence in psychology is fluid vs. crystallized intelligence. While crystallized intelligence results from the accumulation of knowledge, facts, and abilities learned over one's life, fluid intelligence involves the capacity to reason and think in a more flexible manner. This hypothesis, which was first put forth by Raymond Cattell in 1963, argues that a person's total level of intelligence is the result of a multitude of skills that interact and support one another.

According to Raymond Cattell, a more accurate definition of fluid intelligence is “The ability to perceive relationships independent of previous specific practice or instruction concerning those relationships.” Therefore, fluid intelligence is considered independent of learning, experience, and education and involves thinking, reasoning abstractly. Instead, it is employed to solve new issues that can’t be addressed with existing knowledge. A few examples of fluid intelligence include developing problem-solving strategies, analyzing statistics, philosophical thinking, and solving puzzles or abstract problems. It typically begins to decline during late adulthood, along with cognitive abilities linked to fluid intelligence.

On the other hand, crystallized intelligence involves knowledge that comes from prior learning and past experiences. Examples include learning a text by heart, memorizing vocabulary, remembering how to do something, and recalling dates and places. Unlike fluid intelligence, crystallized intelligence tends to increase with age, because, with more learning and experience, more of this intelligence is built up.

Differences between these types of intelligence

Unlike fluid intelligence, which relates to current ability, involves being open to learning new things, and declines with age, crystallized intelligence refers to prior learning, involves remembering specific information, and increases with age. Despite being regarded as different and disctinct, both fluid and crystallized intelligence are factors of what Cattell considered general intelligence. Additionally, these intelligence types have a tendency to shift over the course of life, with certain mental abilities peaking at different points.

Fluid intelligence is thought to peak early in life, although it may peak as late as age 40. Crystallized intelligence, however, often peaks later in life, primarily between the ages of 60 and 70. Both types of intelligence increase throughout childhood and adolescence, but the latter continues growing over time. In contrast, many characteristics of fluid intelligence peak throughout adolescence and gradually decline after the age of 30 or 40.

Tests that measure these types of intelligence

Fluid intelligence

  1. Raven’s Progressive Matrices Test (RPM) is a non-verbal evaluation that requires the subject to examine various shapes and select them to complete a pattern.

  2. Woodcock-Johnson Test of Cognitive Abilities assesses cognitive abilities and achievement and is often given to children to evaluate them for advanced academic courses.

  3. Weschler Intelligence Scale for Children measures verbal, logical, and memory skills, and is primarily used to evaluate children between the ages of six and sixteen.

Crystallized intelligence

  1. Vocabulary and general knowledge tests are a great way to test crystallized intelligence, given that it is accumulated knowledge acquired through life.

  2. Wechsler Adult Intelligence Scale (WAIS) is a test of cognitive ability designed for adults that provides separate scores for different areas rather than an overall intelligence score.

Can you improve fluid and crystallized intelligence?

Although fluid intelligence can be improved, training it can be challenging. A few ways to do so are by challenging yourself, changing up your routine, thinking creatively, and socializing regularly. As for crystallized intelligence, it can be improved through learning, as this will lead to the accumulation of knowledge. Some ways are through learning new languages, learning new skills, taking a class, and reading books.

Looking at these types of intelligence raises the question of whether one is more important than the other, and it has been shown that both are equally important for everyday life. In a psychology exam, for example, you might use fluid intelligence to come up with solutions to a statistics problem, but you will also need to employ crystallized intelligence to remember the exact formulas you need to use. Therefore, though each type of intelligence is distinct, they frequently overlap. Crystallized intelligence can be formed through the investment of fluid intelligence when information is learned, and by using fluid intelligence to reason and think about problems, this information can be transferred to long-term memory and become a component of crystallized intelligence.


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