INTELLIGENCE
It is proven to be very di cult to de ne the exact meaning of intelligence, since it’s a mental
construct that can't be directly observed. There are di erent theories on intelligence:
• Implicit theories = theories from non experts, can not be empirically tested
• Explicit theories = theories from experts, can be empirically tested
Experts determined 6 essential components in intelligence: abstract reasoning, problem-solving
abilities, capacity to acquire knowledge, memory, adaptation to the environment and mental
speed. De nitions of intelligence are proven to be culturally speci c. Implicit theories of
intelligence state the theories formed by how regular people view intelligence.
• Incremental theory = intelligence is malleable
• Entity theory = intelligence is innate and can’t be changed
These implicit theories can also a ect emotions and self-regulations. Research showed that
students who believed in the entity theory experience more negative emotions and self-
handicaps, while students who believe in the incremental theory experience more positive
emotions and self-regulate more. Three types of approaches to intelligence are important: the
psychometric approach (measurement of psychological functions and processes), the cognitive
experiential approach (associated cognitive processes), and the biological approach (causes of
intelligence from the biological eld).
PSYCHOMETRIC APPROACHES
= measuring psychological functions and processes
• Galton (late 1800)
➡Galton was interested in measuring individual di erences in physical and complex mental
attributes. He proposed that individuals who can detect very subtle changes have better
mental ability tan those who can only detect changes that are more obvious or less subtle.
according to Galton, intelligence is inheritable, everyone is born with a certain ability.
• James McKeen Cattell
➡Catell was the rst to use the term ‘mental test’. He contributed to the measurements of
individual di erences by concentrating on improving measurements of sensory functions
such as reaction speed. He also used a ranking system to make statements about an
individuals psychological functions.
• Binet (1904)
➡Binet is credited as the founder of intelligence testing. Together with Theodore Simon he
developed the Binet-Simon scale of intelligence that consisted of 30 tasks which were
related to everyday life and ranked in order of increasing di culty. The level at which the
task was completed gave an indication of the mental age of the child, which could then be
compared to the performance of other similar aged children.
➡Criticism = according to the test, the mental age no longer increases after a certain age,
which would indicate that intelligence decreases when you get older, which is not true.
• Herderschee (1919)
➡Dirk Herderschee standardized and broadened the Binet-Simon test, which he called the
Binet-Herderschee test. It consisted of tasks and questions such as naming objects and
repeating numbers. This test was used to identify mentally retarded children.
➡Criticism = the test created a bias towards verbal and scholastic knowledge, and the order
of presenting items of increasing di culty was imperfect.
• Terman (1916)
➡Lewis Terman uses the Binet-scale on Californian children; the Stanford-Binet scale. This
scale has proven to be a success, due to the methodological approach of Terman. He
compared children’s presentations to those of other children in the same age group, which
we call standardized testing.
• Stern (1912) = founder of IQ
➡Wilhelm Stern introduced the Intelligence Quotiënt (IQ). The IQ is calculated by the
following formula: mental age / chronological age X 100 . The average IQ is 100.
Measuring intelligence in this way was usable with children but not with adults, because the
cognitive development in adults doesn’t increase at the same speed as with children.
• Yerkes
➡Robert Yerkes was asked to develop a test that can be executed in a group setting, to
recruit people for the US army. He came up with the Army Alpha test for English speaking
participants, and the Army Beta test for not English speakers and illeterates.
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, • Spearman = general intelligence
➡Charles Spearman proposed the theory of general intelligence, g. He used factor analysis
to assess interrelationships between intellectual task performance. Factor analysis is a
statistical method that summarizes or reduces the complexities in a group of variables, or in
this case, a group of intellectual tasks. Tasks that are highly intercorrelated are grouped
together statistically to form broader but fewer elements called factors. Spearman labeled
the largest factor as g. He proposed that underlying all of the intercorrelated human
intelligent behaviors is g; the mental energy possessed by each person, which can be
transferred from one mental task to another. He noted that a person’s scores on a range of
intellectual tasks tended to be intercorrelated (high on several tasks means high on other
tasks), which he called positive manifold.
➡In addition to g, Spearman stated that there are also several speci c skills, s, which can be
responsible for an individual’s performance on a speci c task. Summarized, an individual’s
performance is determined by g, but also by a speci c skill s.
➡Criticism = the concept of g is controversial > some researchers think that it’s the result of
the statistical method used and that therefore the theory is more statistically driven than
psychologically driven.
➡First theory with a hierarchic model
• Wechsler (1939 , 1958)
➡Wechsler rst developed the Wechsler-Bellevue scale and later the Wechsler Adult
Intelligence Test. He de ned intelligence as both ‘the global capacity of a person to act
purposefully, to think rationally, and to deal e ectively with his or her environment’ and an
aggregate of speci c abilities. There are two di erences between Wechsler’s test and other
tests. Firstly, he used the same test items to test all individuals. The point at which an item
was failed identi ed the upper limit of the individual’s ability. The second di erence is that he
used deviation IQ to replace the mental age IQ concept. Deviation IQ is calculated by the
following formula: actual test score / expected test score for age X 100 . These scores
form the norm for the test, which can di er from country to country. Everyone who scores
higher than the normative sample of the same age group, is deemed to be higher in
intelligence. The majority of the normal population has an IQ score between 85 and 115.
• Thurstone (1938)
➡Thurstone proposed that g is not the prominent factor of intelligence, but that
there are 7 more important factors that he called primary mental abilities.
He formed the rst multifactor theory of intelligence. The 7 mental
capacities are: verbal comprehension, word uency, number, space,
associate memory, perceptual speed and reasoning. This approach highlights
the importance of speci c abilities when describing a person’s ability.
• Raymond Catell (1963) = two-factor theory
➡Catell proposed the two-factor theory, in which he spliced g into two factors of intelligence:
➡Crystallized intelligence (Gc) = factual knowledge acquired by education and throughout
life. It is accumulative and therefore increases over time, and also less a ected by brain
damage. It can be measured with the Wechsler’s Vocabulary subtest or the Raven’s Mill
Hill Vocabulary tests.
➡Fluid intelligence (Gf) = the ability to see relationships between ideas and objects, and to
solve problems through reasoning. It decreases over time.
• Guilford (1960)
➡Guilford expanded the Thurstone theory and proposed a new multi-factor theory of
intelligence. He stated that there are 120 elementary abilities that can be organized or
described using three dimensions:
➡Operations = the type of mental processing that the individual uses (evaluation,
convergent production, memory, cognition)
➡Contents = the materials that are being processed (visual, auditory, symbolic, behavioral)
➡Products = how information is stored or processed (classes, relations, systems)
➡Criticism = the theory is very detailed and the practical applications are limited, not widely
accepted by psychologists and not very realistic
HIERARCHICAL THEORIES
= theories that contain components that are organized in a hierarchy
• Vernon
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It is proven to be very di cult to de ne the exact meaning of intelligence, since it’s a mental
construct that can't be directly observed. There are di erent theories on intelligence:
• Implicit theories = theories from non experts, can not be empirically tested
• Explicit theories = theories from experts, can be empirically tested
Experts determined 6 essential components in intelligence: abstract reasoning, problem-solving
abilities, capacity to acquire knowledge, memory, adaptation to the environment and mental
speed. De nitions of intelligence are proven to be culturally speci c. Implicit theories of
intelligence state the theories formed by how regular people view intelligence.
• Incremental theory = intelligence is malleable
• Entity theory = intelligence is innate and can’t be changed
These implicit theories can also a ect emotions and self-regulations. Research showed that
students who believed in the entity theory experience more negative emotions and self-
handicaps, while students who believe in the incremental theory experience more positive
emotions and self-regulate more. Three types of approaches to intelligence are important: the
psychometric approach (measurement of psychological functions and processes), the cognitive
experiential approach (associated cognitive processes), and the biological approach (causes of
intelligence from the biological eld).
PSYCHOMETRIC APPROACHES
= measuring psychological functions and processes
• Galton (late 1800)
➡Galton was interested in measuring individual di erences in physical and complex mental
attributes. He proposed that individuals who can detect very subtle changes have better
mental ability tan those who can only detect changes that are more obvious or less subtle.
according to Galton, intelligence is inheritable, everyone is born with a certain ability.
• James McKeen Cattell
➡Catell was the rst to use the term ‘mental test’. He contributed to the measurements of
individual di erences by concentrating on improving measurements of sensory functions
such as reaction speed. He also used a ranking system to make statements about an
individuals psychological functions.
• Binet (1904)
➡Binet is credited as the founder of intelligence testing. Together with Theodore Simon he
developed the Binet-Simon scale of intelligence that consisted of 30 tasks which were
related to everyday life and ranked in order of increasing di culty. The level at which the
task was completed gave an indication of the mental age of the child, which could then be
compared to the performance of other similar aged children.
➡Criticism = according to the test, the mental age no longer increases after a certain age,
which would indicate that intelligence decreases when you get older, which is not true.
• Herderschee (1919)
➡Dirk Herderschee standardized and broadened the Binet-Simon test, which he called the
Binet-Herderschee test. It consisted of tasks and questions such as naming objects and
repeating numbers. This test was used to identify mentally retarded children.
➡Criticism = the test created a bias towards verbal and scholastic knowledge, and the order
of presenting items of increasing di culty was imperfect.
• Terman (1916)
➡Lewis Terman uses the Binet-scale on Californian children; the Stanford-Binet scale. This
scale has proven to be a success, due to the methodological approach of Terman. He
compared children’s presentations to those of other children in the same age group, which
we call standardized testing.
• Stern (1912) = founder of IQ
➡Wilhelm Stern introduced the Intelligence Quotiënt (IQ). The IQ is calculated by the
following formula: mental age / chronological age X 100 . The average IQ is 100.
Measuring intelligence in this way was usable with children but not with adults, because the
cognitive development in adults doesn’t increase at the same speed as with children.
• Yerkes
➡Robert Yerkes was asked to develop a test that can be executed in a group setting, to
recruit people for the US army. He came up with the Army Alpha test for English speaking
participants, and the Army Beta test for not English speakers and illeterates.
fi ff fi ffi fi ff ffi
fi ff ff ffi fi
, • Spearman = general intelligence
➡Charles Spearman proposed the theory of general intelligence, g. He used factor analysis
to assess interrelationships between intellectual task performance. Factor analysis is a
statistical method that summarizes or reduces the complexities in a group of variables, or in
this case, a group of intellectual tasks. Tasks that are highly intercorrelated are grouped
together statistically to form broader but fewer elements called factors. Spearman labeled
the largest factor as g. He proposed that underlying all of the intercorrelated human
intelligent behaviors is g; the mental energy possessed by each person, which can be
transferred from one mental task to another. He noted that a person’s scores on a range of
intellectual tasks tended to be intercorrelated (high on several tasks means high on other
tasks), which he called positive manifold.
➡In addition to g, Spearman stated that there are also several speci c skills, s, which can be
responsible for an individual’s performance on a speci c task. Summarized, an individual’s
performance is determined by g, but also by a speci c skill s.
➡Criticism = the concept of g is controversial > some researchers think that it’s the result of
the statistical method used and that therefore the theory is more statistically driven than
psychologically driven.
➡First theory with a hierarchic model
• Wechsler (1939 , 1958)
➡Wechsler rst developed the Wechsler-Bellevue scale and later the Wechsler Adult
Intelligence Test. He de ned intelligence as both ‘the global capacity of a person to act
purposefully, to think rationally, and to deal e ectively with his or her environment’ and an
aggregate of speci c abilities. There are two di erences between Wechsler’s test and other
tests. Firstly, he used the same test items to test all individuals. The point at which an item
was failed identi ed the upper limit of the individual’s ability. The second di erence is that he
used deviation IQ to replace the mental age IQ concept. Deviation IQ is calculated by the
following formula: actual test score / expected test score for age X 100 . These scores
form the norm for the test, which can di er from country to country. Everyone who scores
higher than the normative sample of the same age group, is deemed to be higher in
intelligence. The majority of the normal population has an IQ score between 85 and 115.
• Thurstone (1938)
➡Thurstone proposed that g is not the prominent factor of intelligence, but that
there are 7 more important factors that he called primary mental abilities.
He formed the rst multifactor theory of intelligence. The 7 mental
capacities are: verbal comprehension, word uency, number, space,
associate memory, perceptual speed and reasoning. This approach highlights
the importance of speci c abilities when describing a person’s ability.
• Raymond Catell (1963) = two-factor theory
➡Catell proposed the two-factor theory, in which he spliced g into two factors of intelligence:
➡Crystallized intelligence (Gc) = factual knowledge acquired by education and throughout
life. It is accumulative and therefore increases over time, and also less a ected by brain
damage. It can be measured with the Wechsler’s Vocabulary subtest or the Raven’s Mill
Hill Vocabulary tests.
➡Fluid intelligence (Gf) = the ability to see relationships between ideas and objects, and to
solve problems through reasoning. It decreases over time.
• Guilford (1960)
➡Guilford expanded the Thurstone theory and proposed a new multi-factor theory of
intelligence. He stated that there are 120 elementary abilities that can be organized or
described using three dimensions:
➡Operations = the type of mental processing that the individual uses (evaluation,
convergent production, memory, cognition)
➡Contents = the materials that are being processed (visual, auditory, symbolic, behavioral)
➡Products = how information is stored or processed (classes, relations, systems)
➡Criticism = the theory is very detailed and the practical applications are limited, not widely
accepted by psychologists and not very realistic
HIERARCHICAL THEORIES
= theories that contain components that are organized in a hierarchy
• Vernon
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