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The Theory of Fluid Reasoning

The Theory of Fluid Reasoning

Updated on May 27, 2022

Reviewed by Rebecca Deltoro, BS (Psychology) , Psychologist (Provisional)

What is Fluid Reasoning & How to Improve Fluid Reasoning Skills

There are some people who find solutions to the most complex problems. Others get compliments for their out-of-the-box problem-solving skills. Are you one of those people? If yes, chances are that you possess superior fluid reasoning skills.

“There are no great limits to growth because there are no limits of human intelligence, imagination, and wonder.”


Fluid Reasoning Infographic

The Theory of Fluid Reasoning
The Theory of Fluid Reasoning

What is Fluid Reasoning?

Fluid Reasoning is the ability to find unique solutions to unique problems. It is not based on any past experiences or knowledge. Rather, it is solely based on the intelligence of the human mind in new situations.

Fluid Reasoning (FR) is the ability to find solutions to novel problems. When you experience a new challenge, it helps you explore all the possible ways to solve the problem in a unique manner. It is a kind of cognitive skill that displays unique problem-solving abilities in a person.

We live in a world where information is readily available. Usually, the moment we face a question, we “Google” it.

It is the most common approach to solve anything. And just like that, we decline our brain’s effectiveness. In short, “What we don’t use, we lose” holds true in the context of our brain.

Origin of Fluid Reasoning

In the year 1963, a psychologist named Raymond Cattell divided human intelligence into two types – crystallized intelligence and fluid intelligence. Later, Cattell along with one of his students named John L. Horn did further research upon this.

Development of Fluid Reasoning

Fluid Reasoning follows a graph-like saturation, wherein it declines after reaching a certain point. The fluid intelligence grows throughout young age, peaks around the 20s to 30s, and is relatively stable till the 60s; after which it gradually declines.

On the other hand, crystallized intelligence grows with time and age.

Ordinarily, the development of fluid reasoning skills in an individual is also largely dependent upon the working memory capacity. Also referred to as short-term memory, it appears to have a direct correlation with fluid intelligence in a person.

Crystallized intelligence, on the other hand, is related to long-term memory and exposure.

Relationship Between Fluid Reasoning and Fluid Intelligence

The two terms have often been used interchangeably. However, they are slightly different from one another. Fluid intelligence is more of a quality that comes out of fluid reasoning abilities.

For instance, when you apply your own ideas to a complex situation, you apply fluid reasoning skills. This, in turn, results in higher fluid intelligence.

In simple terms, fluid reasoning is often used as a verb and fluid intelligence as an adjective. In other words, fluid intelligence is the result of fluid reasoning abilities.


When faced with a mathematical problem you have solved a few times before, you can easily solve it using past methods. This is crystallized intelligence.

However, if you are able to solve a new type of problem using your own logic and understanding, you have applied fluid intelligence in that case.

Difference Between Fluid Intelligence and Crystallised Intelligence

As seen above, fluid intelligence and crystallized intelligence are completely different terms. They cannot be used interchangeably and thus, it is pertinent to know about their differences.

Let us look at some of the differences between fluid and crystallized intelligence:

Fluid Intelligence Crystallized Intelligence
Application of a unique solution to unique problems Application of knowledge and experience to solve a problem
It grows during the young age, peaks around 20s, remains relatively stable till 60s and then gradually declinesIt grows continuously till old age and is usually low in young age
It does not depend on learning and education system It is highly dependent on the learning and education system
Involves the application of reasoning and logic Involves the application of learning and knowledge
Fluid Intelligence Graph as per Age
Fluid Intelligence Graph as per Age
Crystallized Intelligence Graph as per Age
Crystallized Intelligence Graph as per Age

Importance of Fluid Reasoning

Fluid reasoning abilities in children tend to be higher than in adults. However, we cannot undermine its importance at any stage in life. It plays a vital role in learning to process new information and deal with new situations.

Let us have a look at some of the reasons why fluid reasoning is important:

  1. It helps children to identify and observe new patterns and situations. They gain the ability to experiment and find solutions on their own. Thus, the reliance on other factors lessens with time.
  2. With a unique approach to analyzing things, children perform well in academics too. They deviate from the typical approach of cramming up the content. Instead, they focus on devising their own learning strategy.
  3. When a person performs better in challenging situations, their confidence level boosts up. We all know that confidence is the key to success. Who doesn’t like a good dose of healthy confidence to sail through this tough life?
  4. Fluid reasoning abilities help you connect dots between unrelated situations. What seems impossible and unrelated starts making sense now.
  5. It shapes innovation and independent thinking. When you encourage your children to think independently, they grow up to be innovators, inventors, and independent thinkers.

Measurement of Fluid Reasoning Index

Over the years, many psychologists have come up with various measures to determine human intelligence. Although each mindset works differently, such tests do provide some understanding of the human brain.

Some of the common tests to determine Fluid Intelligence are as follows:

  1. Raven’s Progressive Matrices (RPM) – The RPM test is one of the most popular tests used for assessing general intelligence in humans. It is non-verbal in nature and is usually composed of multiple-choice questions.

    The questions are usually in the form of progressive matrices. We see such questions in the reasoning aptitude tests used for various examinations.
  2. Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V) – Typically used for children between the age group of 6 to 16, WISC -V is also a commonly used IQ test. With these tests, a child’s cognitive abilities can be assessed quite effectively. They assess a child’s verbal as well as performance IQ.
  3. Wechsler Adult Intelligence Scale (WAIS-IV)– Just as the WISC-V assesses the cognitive abilities of children, the WAIS-IV is a test for adults. It consists of ten subtests that determine the core mental abilities of a person.
  4. Woodcock–Johnson Tests of Cognitive Abilities – This is a set of tests used to determine cognitive abilities in primarily nine broad areas like long and short-term memory, fluid reasoning, reading comprehension, etc. Also, it is a comprehensive test that includes almost 20 sub-tests.
  5. Cattell Culture Fair Intelligence Test (CFIT) – Founded by Raymond Cattell in the year 1949, CFIT is a test that measures one’s cognitive skills free from external factors. These include any kind of external influences, cultural, environmental and societal factors, etc.

    While testing, the participants performed various tests consisting of non-verbal visual puzzles divided among three scales of judgment. After that, the test was revised to suit the existing conditions.

The first WAIS test was published in 1955 by David Wechsler. With updated understanding and subsequent revisions, these tests were republished from time to time (WAIS-I, II, III, and so on).

The latest WAIS-IV test was released in 2008 by Pearson Group under their registered trademark. Similarly, all the other tests have been republished with suitable revisions from time to time.

How to Improve Fluid Reasoning Skills?

It is said that fluid intelligence is comparatively higher in children than in adults. However, it is not something that cannot be mastered. Training your brain using various techniques can definitely sharpen your cognitive development.

Let us look at some of the ways to sharpen your fluid intelligence levels:

1. Challenge Yourself

To hone your fluid intelligence levels, you should learn to accept new challenges. Do not step back the next time you face something new or difficult. Instead, take this opportunity to use your brain muscles and let your creative juices flow.

Were you never able to solve Rubik’s Cube? Or have you always feared that it is too much of a task? Try again this time. Engage in challenging puzzles and try your best to solve them. This will give your brain all the workouts it needs. Moreover, this will improve your fluid intelligence levels.

2. Ask Question

In this era of readily available information, never stop being curious. The more you question, the more your mind activates.

When you accept everything as it is, you do not give your brain a chance to learn something new. Consequently, this results in a sharp decline in your fluid intelligence levels.

The next time you attend a training session or a class, make sure you ask five new questions to the trainer. As a result, this practice will condition your brain to think out-of-the-box and form your own perspectives.

3. Break the Pattern

Do you always make the same moves in chess? Or, do you often depend on the same strategy to pass exams? If so, break that pattern and try something new! You may never know the possibility of other options until you try them.

In any event, take calculated risks, break the pattern, and free your mind from mediocrity.

4. Seek New Experiences

It is never too late to learn anything new in life. To improve fluid reasoning levels, the brain needs to feed on something new from time to time.

For example, indulge in any new activity that allows your brain to step outside its comfort zone. The concept formation function that arises from learning something new will contribute largely to IQ development.

5. Socialize

The more you expose yourself to new situations, the more your brain activates. For instance, why do you feel the most inspired after you meet highly energetic and positive people?

It is because they affect how you think. Therefore, always look forward to socializing and meeting new people. You never know who inspires or motivates you to think uniquely.

6. Exercise and Meditation

Researchers from all over the world have suggested that exercise is directly related to improved brain functioning. Exercise has proved to improve memory due to the growth of good hormones in the body.

Some of the studies have investigated the relationship between physical exercises combined with working memory training and fluid intelligence.

7. Improve your Lifestyle

We come across numerous lifestyle tips almost on a daily basis. Do you know that improving your way of living can positively impact your fluid intelligence?

Improved habits like adequate sleep, quitting drinking and smoking, healthy eating, etc. cause your brain to improve neural health. After all, a healthy way of life allows one to think more clearly and rationally.

8. Ditch the Easy

Going after the easy and known path is a sure-shot way to kill your intelligence. When you stop stepping out of your comfort zone, your brain starts getting redundant.

As a result, it relies mostly on what is known. To fuel your mind activity, keep feeding the brain with challenges out of your comfort zone.

In other words, ditch the easy way and challenge your brain to opt for the path. It will seem difficult at first, but the joy of accomplishment will be unreal.

Fluid Reasoning Examples

  • Problem-solving case studies and riddles
  • Games like Scrabble, Boggle, Jenga, Chess, etc.
  • Crossword Puzzles 
  • Rubik’s Cube
  • Memory Quizzes
  • Spontaneous writing on new topics
  • Reasoning games
  • Traveling to New Places (preferably with a new set of people)

While these activities do help in sharpening your IQ skills, they tend to lose their importance as and when you master them. Upon mastering the activities, your mind begins to use more of the stored knowledge.

Thus, this results in the application of crystallized intelligence more than fluid intelligence. Hence, the purpose seems defeated in the long run.

Closing Thoughts

We now know that fluid reasoning abilities tend to decline with age. Nonetheless, keeping it consistent is not rocket science. To sum up:

  • keep challenging your brain constantly to keep your fluid intelligence high
  • do not fear to venture out of your comfort zone, and
  • flex your brain muscles by keeping in mind the tips we shared

Article Sources


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