Fluid and crystallized intelligence
Encyclopedia
In psychology
, fluid and crystallized intelligence (abbreviated Gf and Gc, respectively) are factors of general intelligence
originally identified by Raymond Cattell
. Concepts of fluid and crystallized intelligence were further developed by John L. Horn, the primary student of Raymond Cattell.
Fluid intelligence or fluid reasoning is the capacity to think logically and solve problems in novel situations, independent of acquired knowledge. It is the ability to analyze novel problems, identify patterns and relationships that underpin these problems and the extrapolation of these using logic. It is necessary for all logical problem solving, especially scientific, mathematical and technical problem solving. Fluid reasoning includes inductive reasoning
and deductive reasoning
.
Crystallized intelligence is the ability to use skills, knowledge, and experience. It should not be equated with memory or knowledge, but it does rely on accessing information from long-term memory.
Crystallized intelligence is one’s lifetime or intellectual achievement, as demonstrated largely through one's vocabulary and general knowledge
. This improves somewhat with age, as experiences tend to expand one's knowledge.
The terms are somewhat misleading because one is not a "crystallized" form of the other. Rather, they are believed to be separate neural and mental systems. Crystallized intelligence is indicated by a person's depth and breadth of general knowledge, vocabulary, and the ability to reason
using words and numbers. It is the product of educational and cultural experience in interaction with fluid intelligence.
Fluid and crystallized intelligence are thus correlated with each other, and most IQ tests attempt to measure both varieties. For example, the Wechsler Adult Intelligence Scale
(WAIS) measures fluid intelligence on the performance scale and crystallized intelligence on the verbal scale. The overall IQ score is based on a combination of these two scales.
, or g. Although formally recognized by Cattell, the distinction was foreshadowed by Charles Spearman
who originally developed the theory of g and made a similar observation regarding the difference between eductive and reproductive mental ability.
According to Cattell, "...it is apparent that one of these powers… has the 'fluid' quality of being directable to almost any problem. By contrast, the other is invested in particular areas of crystallized skills which can be upset individually without affecting the others." Thus, his claim was that each type, or factor, was independent of the other, though many authors have noted an apparent interdependence of the two.
Fluid intelligence is predominant in individuals with Autism spectrum
disorders, including Asperger syndrome
.
Crystallized intelligence is possibly more amenable to change as it relies on specific, acquired knowledge. For example, a child who has just learned to add numbers now owns a new piece of crystallized intelligence; but his or her general ability to learn and understand, Gf, has not been altered. An example of the flexibility of, or ability to revise, crystallized intelligence can be seen in beliefs about Santa Claus. A five year-old child may believe that Santa Claus lives at the North Pole. Later, when the child is eight years old, he learns there is no Santa Claus. His belief that Santa lives at the North Pole was then invalidated and new knowledge is gained: there is no Santa Claus. The prior belief was revised in order to accommodate the new learning. Vocabulary tests and the verbal subscale of the Wechsler Adult Intelligence Scale
are considered good measures of Gc.
Not surprisingly, people with a high capacity of Gf tend to acquire more Gc knowledge and at faster rates. This is sometimes called investment. Researchers have found that criminals have disproportionately low levels of crystallized intelligence. This may be a result of these people investing their ability into skills that are not measured on IQ tests.
Some researchers have linked the theory of fluid and crystallized intelligence to Piaget
's conception of operative intelligence and learning. Fluid ability and Piaget's operative intelligence both concern logical thinking and the education of relations. Crystallized ability and Piaget's treatment of everyday learning reflect the impress of experience. Like fluid ability's relation to crystallized intelligence, Piaget's operativity is considered to be prior to, and ultimately provides the foundation for, everyday learning.
, the Raven Progressive Matrices
(RPM), and the performance subscale of the WAIS
are measures of Gf. The RPM is one of the most commonly used measures of fluid abilities. It is a non-verbal multiple choice test. Participants have to complete a series of drawings by identifying relevant features based on the spatial organization of an array of objects, and choosing one object that matches one or more of the identified features.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2695390/figure/F1/ This task assesses the ability to consider one or more relationships between mental representations or relational reasoning. Propositional analogies and semantic decision tasks are also used to assess relational reasoning.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2525981/figure/F1/
Standardized IQ tests such as those used in psychoeducational assessment also include tests of fluid intelligence. In the Woodcock-Johnson Tests of Cognitive Abilities
Gf is assessed by two tests: Concept Formation (Test 5) in the Standard Battery and Analysis Synthesis (Test 15) in the Extended Battery. On Concept Formation tasks,the individual has to apply concepts by inferring the underlying “rules” for solving visual puzzles that are presented in increasing levels of difficulty. Individuals at the preschool level have to point to a shape that is different from others in a set. As the level of difficulty increases, individuals increasingly demonstrate an understanding of what constitutes a key difference (or the “rule”) for solving puzzles involving one to one comparisons, and on later items identifying common differences among a set of items. For more difficult items, individuals need to understand the concept of “and” (e.g. solution must have some of this and some of that) and the concept of “or” (e.g. to be inside a box, the item must be either this or that). The most difficult items require fluid transformations and cognitive shifting between the various types of concept puzzles that the examinee has worked with previously.
Concept Formation tasks assess inductive reasoning ability. In the Analysis-Synthesis test, the individual has to learn and orally state the solutions to incomplete logic puzzles that mimic a miniature mathematics system. The test also contains some of the features involved in using symbolic formulations in other fields such as chemistry and logic. The individual is presented with a set of logic rules, a “key” that is used to solve the puzzles. The individual has to determine the missing colors within each of the puzzles using the key. Complex items present puzzles that require two or more sequential mental manipulations of the key to derive a final solution. Increasingly difficult items involve a mix of puzzles that require fluid shifts in deduction, logic, and inference. Analysis Synthesis tasks assess general sequential reasoning.
In the Wechsler Intelligence Scale for Children
-IV (WISC IV) the Perceptual Reasoning Index contains two subtests that assess Gf: Matrix Reasoning, which involves induction and deduction, and Picture Concepts, which involves induction. In the Picture Concepts task, children are presented a series of pictures on two or three rows and asked which pictures (one from each row) belong together based on some common characteristic. This task assesses the child's ability to discover the underlying characteristic (e.g. rule, concept, trend, class membership) that governs a set of materials. Matrix Reasoning also tests this ability as well as the ability to start with stated rules, premises, or conditions and to engage in one or more steps to reach a solution to a novel problem (deduction). In the Matrix Reasoning test, children are presented a series or sequence of pictures with one picture missing. Their task is to choose the picture that fits the series or sequence from an array of five options. Since Matrix Reasoning and Picture Concepts involve the use of visual stimuli and do not require expressive language they are considered to be non-verbal tests of Gf.
Within the corporate environment fluid intelligence is a predictor of a person's capacity to work well in environments charactrerised by complexity, uncertainty, and ambiguity. The Cognitive Process Profile (CPP) measures a person's fluid intelligence and cognitive processes. It maps these against suitable work environments according to Elliott Jacques Stratified Systems Theory.
Working memory
capacity is closely related to fluid intelligence, and has been proposed to account for individual differences in Gf. Furthermore, recent research suggests that cognitive exercise can increase working memory and also improve Gf.
, the anterior cingulate cortex
, and other systems related to attention and short-term memory. Crystallized intelligence appears to be a function of brain regions that involve the storage and usage of long-term memories, such as the hippocampus
.
Susanne M. Jaeggi, from the University of Michigan, found that healthy young adults, who practiced a demanding working memory task (dual n-back) approximately 25 minutes per day for between 8 and 19 days, had statistically significant increases in their scores on a matrix test of fluid intelligence taken before and after the training than a control group who did not do any training at all. [Jaeggi, Susanne M.; Buschkuehl, Martin; Jonides, John; and Perrig, Walter J. (2008). "Improving fluid intelligence with training on working memory." PNAS- Proceedings of the National Academy of Sciences]
More recently, a study conducted at the University of Technology in Hangzhou, China supports Jaeggi's results independently. After student subjects were given a 10 day training regime based on the dual-n back working memory theory, the students were tested on Raven's Standard Progressive Matrices. Their scores were found to have increased significantly. [Qiu Feiyue; Wei Qinqin (2010). "Study on Improving Fluid Intelligence through Cognitive Training System Based on Gabor Stimulus" Information Science and Engineering]
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
, fluid and crystallized intelligence (abbreviated Gf and Gc, respectively) are factors of general intelligence
General intelligence
General intelligence may refer to:* general intelligence factor in psychology* Intelligence* strong AI, an artificial intelligence that matches or exceeds human intelligence...
originally identified by Raymond Cattell
Raymond Cattell
Raymond Bernard Cattell was a British and American psychologist, known for his exploration of many areas in psychology...
. Concepts of fluid and crystallized intelligence were further developed by John L. Horn, the primary student of Raymond Cattell.
Fluid intelligence or fluid reasoning is the capacity to think logically and solve problems in novel situations, independent of acquired knowledge. It is the ability to analyze novel problems, identify patterns and relationships that underpin these problems and the extrapolation of these using logic. It is necessary for all logical problem solving, especially scientific, mathematical and technical problem solving. Fluid reasoning includes inductive reasoning
Inductive reasoning
Inductive reasoning, also known as induction or inductive logic, is a kind of reasoning that constructs or evaluates propositions that are abstractions of observations. It is commonly construed as a form of reasoning that makes generalizations based on individual instances...
and deductive reasoning
Deductive reasoning
Deductive reasoning, also called deductive logic, is reasoning which constructs or evaluates deductive arguments. Deductive arguments are attempts to show that a conclusion necessarily follows from a set of premises or hypothesis...
.
Crystallized intelligence is the ability to use skills, knowledge, and experience. It should not be equated with memory or knowledge, but it does rely on accessing information from long-term memory.
Crystallized intelligence is one’s lifetime or intellectual achievement, as demonstrated largely through one's vocabulary and general knowledge
General knowledge
General knowledge has been defined by differential psychologists as referring to 'culturally valued knowledge communicated by a range of non-specialist media' General knowledge therefore encompasses a wide range of knowledge domains...
. This improves somewhat with age, as experiences tend to expand one's knowledge.
The terms are somewhat misleading because one is not a "crystallized" form of the other. Rather, they are believed to be separate neural and mental systems. Crystallized intelligence is indicated by a person's depth and breadth of general knowledge, vocabulary, and the ability to reason
Reason
Reason is a term that refers to the capacity human beings have to make sense of things, to establish and verify facts, and to change or justify practices, institutions, and beliefs. It is closely associated with such characteristically human activities as philosophy, science, language, ...
using words and numbers. It is the product of educational and cultural experience in interaction with fluid intelligence.
Fluid and crystallized intelligence are thus correlated with each other, and most IQ tests attempt to measure both varieties. For example, the Wechsler Adult Intelligence Scale
Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale intelligence quotient tests are the primary clinical instruments used to measure adult and adolescent intelligence. The original WAIS was published in February 1955 by David Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale...
(WAIS) measures fluid intelligence on the performance scale and crystallized intelligence on the verbal scale. The overall IQ score is based on a combination of these two scales.
Theoretical development
Fluid and crystallized intelligence are discrete factors of general intelligenceGeneral intelligence
General intelligence may refer to:* general intelligence factor in psychology* Intelligence* strong AI, an artificial intelligence that matches or exceeds human intelligence...
, or g. Although formally recognized by Cattell, the distinction was foreshadowed by Charles Spearman
Charles Spearman
Charles Edward Spearman, FRS was an English psychologist known for work in statistics, as a pioneer of factor analysis, and for Spearman's rank correlation coefficient...
who originally developed the theory of g and made a similar observation regarding the difference between eductive and reproductive mental ability.
According to Cattell, "...it is apparent that one of these powers… has the 'fluid' quality of being directable to almost any problem. By contrast, the other is invested in particular areas of crystallized skills which can be upset individually without affecting the others." Thus, his claim was that each type, or factor, was independent of the other, though many authors have noted an apparent interdependence of the two.
Fluid versus crystallized
Fluid intelligence includes such abilities as problem-solving, learning, and pattern recognition. Evidence is consistent with the view that Gf is more affected by brain injury.Fluid intelligence is predominant in individuals with Autism spectrum
Autism spectrum
The term "autism spectrum" is often used to describe disorders that are currently classified as pervasive developmental disorders. Pervasive developmental disorders include autism, Asperger syndrome, Childhood disintegrative disorder, Rett syndrome and Pervasive Developmental Disorder Not Otherwise...
disorders, including Asperger syndrome
Asperger syndrome
Asperger's syndrome that is characterized by significant difficulties in social interaction, alongside restricted and repetitive patterns of behavior and interests. It differs from other autism spectrum disorders by its relative preservation of linguistic and cognitive development...
.
Crystallized intelligence is possibly more amenable to change as it relies on specific, acquired knowledge. For example, a child who has just learned to add numbers now owns a new piece of crystallized intelligence; but his or her general ability to learn and understand, Gf, has not been altered. An example of the flexibility of, or ability to revise, crystallized intelligence can be seen in beliefs about Santa Claus. A five year-old child may believe that Santa Claus lives at the North Pole. Later, when the child is eight years old, he learns there is no Santa Claus. His belief that Santa lives at the North Pole was then invalidated and new knowledge is gained: there is no Santa Claus. The prior belief was revised in order to accommodate the new learning. Vocabulary tests and the verbal subscale of the Wechsler Adult Intelligence Scale
Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale intelligence quotient tests are the primary clinical instruments used to measure adult and adolescent intelligence. The original WAIS was published in February 1955 by David Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale...
are considered good measures of Gc.
Not surprisingly, people with a high capacity of Gf tend to acquire more Gc knowledge and at faster rates. This is sometimes called investment. Researchers have found that criminals have disproportionately low levels of crystallized intelligence. This may be a result of these people investing their ability into skills that are not measured on IQ tests.
Some researchers have linked the theory of fluid and crystallized intelligence to Piaget
Jean Piaget
Jean Piaget was a French-speaking Swiss developmental psychologist and philosopher known for his epistemological studies with children. His theory of cognitive development and epistemological view are together called "genetic epistemology"....
's conception of operative intelligence and learning. Fluid ability and Piaget's operative intelligence both concern logical thinking and the education of relations. Crystallized ability and Piaget's treatment of everyday learning reflect the impress of experience. Like fluid ability's relation to crystallized intelligence, Piaget's operativity is considered to be prior to, and ultimately provides the foundation for, everyday learning.
Factor structure
Fluid intelligence generally correlates with measures of abstract reasoning and puzzle solving. Crystallized intelligence correlates with abilities that depend on knowledge and experience, such as vocabulary, general information, and analogies. Paul Kline identified a number of factors that shared a correlation of at least r=.60 with Gf and Gc. Factors with median loadings of greater than 0.6 on Gf included induction, visualization, quantitative reasoning, and ideational fluency. Factors with median loadings of greater than 0.6 on Gc included verbal ability, language development, reading comprehension, sequential reasoning, and general information. It may be suggested that tests of intelligence may not be able to truly reflect levels of fluid intelligence. Some authors have suggested that unless an individual was truly interested in the problem presented, the cognitive work required may not be performed because of a lack of interest. These authors contend that a low score on tests which are intended to measure fluid intelligence may reflect more a lack of interest in the tasks rather than inability to complete the tasks successfully.Measurement of fluid intelligence
There are various measures that assess fluid intelligence. The Cattell Culture Fair IQ testCattell Culture Fair III
In seeking to develop a culture-fair intelligence or IQ test that separated environmental and genetic factors, Raymond B. Cattell created the CFIT or Culture Fair Intelligence Test. Cattell argued that general intelligence exists and that it consists of fluid intelligence and crystallized...
, the Raven Progressive Matrices
Raven's Progressive Matrices
Raven's Progressive Matrices are non-verbal multiple choice measures of the reasoning component of Spearman's g , which is often referred to as general intelligence. The tests were originally developed by John C. Raven in 1936...
(RPM), and the performance subscale of the WAIS
Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale intelligence quotient tests are the primary clinical instruments used to measure adult and adolescent intelligence. The original WAIS was published in February 1955 by David Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale...
are measures of Gf. The RPM is one of the most commonly used measures of fluid abilities. It is a non-verbal multiple choice test. Participants have to complete a series of drawings by identifying relevant features based on the spatial organization of an array of objects, and choosing one object that matches one or more of the identified features.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2695390/figure/F1/ This task assesses the ability to consider one or more relationships between mental representations or relational reasoning. Propositional analogies and semantic decision tasks are also used to assess relational reasoning.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2525981/figure/F1/
Standardized IQ tests such as those used in psychoeducational assessment also include tests of fluid intelligence. In the Woodcock-Johnson Tests of Cognitive Abilities
Woodcock-Johnson Tests of Cognitive Abilities
The Woodcock-Johnson Tests of Cognitive Abilities is a set of intelligence tests first developed in 1977 by Woodcock and Johnson. It was revised in 1989 and again in 2001; this last version is commonly referred to as WJ-III. They may be administered to children from age two right up to the oldest...
Gf is assessed by two tests: Concept Formation (Test 5) in the Standard Battery and Analysis Synthesis (Test 15) in the Extended Battery. On Concept Formation tasks,the individual has to apply concepts by inferring the underlying “rules” for solving visual puzzles that are presented in increasing levels of difficulty. Individuals at the preschool level have to point to a shape that is different from others in a set. As the level of difficulty increases, individuals increasingly demonstrate an understanding of what constitutes a key difference (or the “rule”) for solving puzzles involving one to one comparisons, and on later items identifying common differences among a set of items. For more difficult items, individuals need to understand the concept of “and” (e.g. solution must have some of this and some of that) and the concept of “or” (e.g. to be inside a box, the item must be either this or that). The most difficult items require fluid transformations and cognitive shifting between the various types of concept puzzles that the examinee has worked with previously.
Concept Formation tasks assess inductive reasoning ability. In the Analysis-Synthesis test, the individual has to learn and orally state the solutions to incomplete logic puzzles that mimic a miniature mathematics system. The test also contains some of the features involved in using symbolic formulations in other fields such as chemistry and logic. The individual is presented with a set of logic rules, a “key” that is used to solve the puzzles. The individual has to determine the missing colors within each of the puzzles using the key. Complex items present puzzles that require two or more sequential mental manipulations of the key to derive a final solution. Increasingly difficult items involve a mix of puzzles that require fluid shifts in deduction, logic, and inference. Analysis Synthesis tasks assess general sequential reasoning.
In the Wechsler Intelligence Scale for Children
Wechsler Intelligence Scale for Children
The Wechsler Intelligence Scale for Children , developed by Dr. David Wechsler, is an individually administered intelligence test for children between the ages of 6 and 16 inclusive that can be completed without reading or writing...
-IV (WISC IV) the Perceptual Reasoning Index contains two subtests that assess Gf: Matrix Reasoning, which involves induction and deduction, and Picture Concepts, which involves induction. In the Picture Concepts task, children are presented a series of pictures on two or three rows and asked which pictures (one from each row) belong together based on some common characteristic. This task assesses the child's ability to discover the underlying characteristic (e.g. rule, concept, trend, class membership) that governs a set of materials. Matrix Reasoning also tests this ability as well as the ability to start with stated rules, premises, or conditions and to engage in one or more steps to reach a solution to a novel problem (deduction). In the Matrix Reasoning test, children are presented a series or sequence of pictures with one picture missing. Their task is to choose the picture that fits the series or sequence from an array of five options. Since Matrix Reasoning and Picture Concepts involve the use of visual stimuli and do not require expressive language they are considered to be non-verbal tests of Gf.
Within the corporate environment fluid intelligence is a predictor of a person's capacity to work well in environments charactrerised by complexity, uncertainty, and ambiguity. The Cognitive Process Profile (CPP) measures a person's fluid intelligence and cognitive processes. It maps these against suitable work environments according to Elliott Jacques Stratified Systems Theory.
Development and physiology
Fluid intelligence, like reaction time, typically peaks in young adulthood and then steadily declines. This decline may be related to local atrophy of the brain in the right cerebellum. Other researchers have suggested that a lack of practice, along with age-related changes in the brain may contribute to the decline. Crystallized intelligence typically increases gradually, stays relatively stable across most of adulthood, and then begins to decline after age 65.Working memory
Working memory
Working memory has been defined as the system which actively holds information in the mind to do verbal and nonverbal tasks such as reasoning and comprehension, and to make it available for further information processing...
capacity is closely related to fluid intelligence, and has been proposed to account for individual differences in Gf. Furthermore, recent research suggests that cognitive exercise can increase working memory and also improve Gf.
Improving fluid intelligence with training on working memory
According to David Geary, Gf and Gc can be traced to two separate brain systems. Fluid intelligence involves the dorsolateral prefrontal cortexDorsolateral prefrontal cortex
The dorsolateral prefrontal cortex , according to a more restricted definition, is roughly equivalent to Brodmann areas 9 and 46. According to a broader definition DL-PFC consists of the lateral portions of Brodmann areas 9 – 12, of areas 45, 46, and the superior part of area 47. These regions...
, the anterior cingulate cortex
Anterior cingulate cortex
The anterior cingulate cortex is the frontal part of the cingulate cortex, that resembles a "collar" form around the corpus callosum, the fibrous bundle that relays neural signals between the right and left cerebral hemispheres of the brain...
, and other systems related to attention and short-term memory. Crystallized intelligence appears to be a function of brain regions that involve the storage and usage of long-term memories, such as the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
.
Susanne M. Jaeggi, from the University of Michigan, found that healthy young adults, who practiced a demanding working memory task (dual n-back) approximately 25 minutes per day for between 8 and 19 days, had statistically significant increases in their scores on a matrix test of fluid intelligence taken before and after the training than a control group who did not do any training at all. [Jaeggi, Susanne M.; Buschkuehl, Martin; Jonides, John; and Perrig, Walter J. (2008). "Improving fluid intelligence with training on working memory." PNAS- Proceedings of the National Academy of Sciences]
More recently, a study conducted at the University of Technology in Hangzhou, China supports Jaeggi's results independently. After student subjects were given a 10 day training regime based on the dual-n back working memory theory, the students were tested on Raven's Standard Progressive Matrices. Their scores were found to have increased significantly. [Qiu Feiyue; Wei Qinqin (2010). "Study on Improving Fluid Intelligence through Cognitive Training System Based on Gabor Stimulus" Information Science and Engineering]
See also
- Raymond CattellRaymond CattellRaymond Bernard Cattell was a British and American psychologist, known for his exploration of many areas in psychology...
- CHC theoryCHC TheoryRecent advances in current theory and research on the structure of human cognitive abilities have resulted in a new empirically derived model commonly referred to as the Cattell–Horn–Carroll theory of cognitive abilities . CHC theory of cognitive abilities is an amalgamation of two similar theories...
- General intelligence factorGeneral intelligence factorThe g factor, where g stands for general intelligence, is a statistic used in psychometrics to model the mental ability underlying results of various tests of cognitive ability...
- IntelligenceIntelligenceIntelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....
- Three stratum theoryThree Stratum TheoryIn 1993 John Carroll published "Human cognitive abilities: A survey of factor-analytic studies", which outlined his hierarchical, Three-Stratum Theory of cognitive abilities....