013368
Subject Lecturer: Bob Pithers
Paper 1
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Intelligence
and Metacognition · Spearman’s One
Factor Theory · Hons’ Theory of
Intelligence Developmental changes in intelligence in the middle
adult years |
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What is intelligence? Describe
one or two attempts to measure this concept. Discuss the contention that
intelligence significantly declines in the middle adult years?
intelligence
and metacognition
The concept of intelligence is easy to understand but hard
to define. In fact there are a lot of definitions by different experts, and
there are different interpretation in different culture. A more modern view of
intelligence is “Metacognition”, where “meta” means “after” and “cognition”
means “the ability to know”. (Shiu, 2004)
Metacognition, according to Shiu(2004), is
Intelligence seemed an ability, knowledge and skills, and
a mental process. Experts tried to understand intelligence, they developed
different theories to explain how intelligence is formed.
Spearman’s One Factor Theory (Spearman 1904, 1927 cited
in Fogart, 1999) suggested that there is a general factor “g” which is a
central pool of energy, and a specific factor which is a unique engine for each
task.
“g” is the knowledge about cognition (offline knowledge),
and specific factor is the ability to use it (online knowledge). Thus the “g”
here is the basic level of intelligence, however, which cannot be measured
directly but only through tests of comprehension, memory and reasoning.
Spearman used tests which required eduction of relation
and correlates as a predictor of academic ability. All the tests of cognitive
tasks he suggested were positively correlated. Although different tasks require
different specific factor, but they all depends on the same dominant single
factor “g”, that is why all cognitive tasks used by Spearman is positively
correlated. Therefore, after deducing the impact of the specific factor, the
cognitive tasks can still reveal the “g”.
Later Hunt (1980) modify the concept “g” by
interpretating it to reflect the ability of individual to organize processing
strategies to face new kinds of mental problem. The concept of “g” is now more
influenced by the concept of “metacognition”.
Godfrey Thompson further suggested that there should be a
large number of independent bonds in mind. He suggested different individual
possessed a subset of the universe of bonds, and that individuals differed in
the number of bonds of intelligence they possessed. This helped to explain
individual differences in intelligence.
Later researchers postulated the “Executive Functioning”
which is a process monitors and controls the use information processing
strategies, suggested that the primary difference between persons of normal
intelligence and the mentally retarded lies in the degree to which people are
able to develop and use information processing strategies.
It gains further support from research by Brody (1992)
cited in Fogart (1999), that there is a high negative correlation between
energy expenditure of the brain and score on a test of abstract reasoning. It
implies that intelligent people spend little energy on a task.
After all, the “g” is understood as basic source of
intelligence which comprise of a subset of bonds, different individual
possessed different subset of bonds, i.e. different “g”, and it marked the
individual difference in intelligence.
The One-Factor Theory undergone modifications as there
was challenges and influences from the Primary Mental Ability (PMA) theory
developed by Thurstone (1938). He used multiple factor analysis to sort out
seven independent primary mental abilities from numerous mental tests and
cognitive tasks, they are S (Space), P (Perceptual Speed), N (Number Facility),
V (Verbal Relations), W (Word Fluency), M (Memory) and I (Induction &
Reasoning).
It is no doubt that all mental tests and cognitive tasks
are positively correlated as stated by Spearman, however, Thurstone further
notice that some tasks or tests have higher correlation than the others. Based
on this, he disapproved the single general intellectual factors but a set of
independent primary mental abilities. However, the positive correlation among
different categories of tests and tasks also suggested that the common factor
among them is the “g”.
Based on the general intelligence factor, Cattell (1963)
has develop another branch of idea. He raised the idea of General Fluid (Gf)
intelligence which is the biological capacity and process for an individual to
acquire knowledge and skills, and General Crystallized (Gc) intelligence which
is the store of knowledge and skills which is influenced by schooling and
acculturation. And that Gf shapes Gc in the early life, and when people grows
older Gf would shows a decline too. (Fogart, 1999)
John Horn (1985), as a student of Cattell reinterpreted
the Gf/Gc model. Gf is the pure ability to perceive, remember, and think about
a wide variety of basic ideas, and it is not affected by cultural background.
Mental ability like spatial reasoning and perceptual speed are best examples of
Gf.
Gc, on the other hand, is the extend to which individuals
have incorporated the vlued knowledge of their culture. It involves
communication, judgement and understanding about everyday affair which are all
culturally valued. Primary mental ability like verbal comprehension, concept
formation logical reasoning, and induction are examples of Gc.
To measure the intelligence of an individual, it involves
testing both the Gf and Gc. Tests about matrices, letter series and figure relations
can be used to test Gf, tests about vocabulary and analogies, remote
associations and social judgment can be used to test Gc. (Fogart, 1999)
Theories of intelligence were developed, however, such
theories are only hypothetical construct. Intelligence is an intangible concept
which cannot be measured directly. Therefore, psychometric test can only
measure the intelligence indirectly by examining the performance on tasks that
depends on the use of intelligence. (Hoyer et al, 2003)
On the other hand, development and use of intelligence is
usually affected by the schemata, which “are generalized knowledge about objects,
situations, and events”. (McCormick and Pressley, 1997, cited in Shiu 2004) The
development of this depends on the cultural background, which is vary from
cultural to cultural, if the same tasks are used universally, it might reveal
the cultural difference rather to reflect the intelligence of an individual.
Other personal factor might also affect the measure of intelligence, like
personality characteristics, motivation, anxiety, fatigue.
Thirdly, there lots of theories regarding intelligence,
some suggest intelligence is a factor, some suggest it is a number of
independent abilities. Therefore, intelligence test should provide individuals
with a wide variety of tasks. One of the most commonly used tests to measure
adult intelligence is the Wechsler Adult Intelligence Scale (WAIS-R), which
consists of 11 subsets with six composing a verbal scale, five to make up a
performance scale. The six verbal subtests include general information, digit
span, vocabulary arithmetic, comprehension, and similarities. The five
performance subtests include picture completion, picture arrangement, block
design, object assembly and digit symbol substitution. (Hoyer et al, 2003)
All tests are positively correlated according to
Spearman, however, the tasks under the same subtest could be more highly
correlated. It is because it is designed to measure the same factor or ability
in a different.
The calculation of IQ is another important issue. There
is a slightly difference in the calculation of children and young adolescents
and the adult. However, it basically sampled a large population to see the
average number of passes for different age groups to form a mental age. The
actual number of passes for an individual forms the chronological age. The
score of a child or a young adolescent is calculated by multiplying the ratio
of mental age to chronological age by 100. Thus regardless the age of the
person tested, the average IQ is always 100. (Hoyer et al, 2003)
It is easy to classify the mental age of children,
however, researchers found that it is difficult to classify the mental age for
the older adult, say 66 and 67. Therefore, for the adults, the score is
obtained by comparing the actual number of passes of an individual to the
average number of passes of the age group. The person passes the same as the
average would be assessed as 100, while passes more or less than the average
would be assessed as above-average or below-average IQ. (Hoyer et al, 2003)
developmental changes in
intelligence in the middle adult years
Traditional thinking about
developmental changes in intelligence thought it an obvious decline as an
individual age. And it is not surprising to find that in a lots of cross
sectional studies, the IQ score decline starting at the late adolescence and
early adulthood, i.e. 20 years old.
However, there were steeper rates of decline
in the speeded WAIS performance subtests. It implies that the slower processing
of the elder brain underlies the poor performance in the nonverbal tests.
Schaie and Willis (1993) (cited in
Hoyer et al, 2003) conducted a study measuring the primary mental abilities of
inductive reasoning, space, number, verbal ability, speed perception,
associative memory to 1,628 community-dwelling adults between 20 and 90 years
of age. The result illustrated
that generally all primary mental abilities declines, however various
components of intelligence decline at different rates with perceptual speed
shows a quick decline and verbal ability shows a gentlest decline. More
importantly, after midlife, performance on the different mental abilities
varies more. Verbal ability and numeric ability is rather constant with a
slight growth at the age around 40.
Despite the general decline of the
overall intelligence, using factor analysis to discern the fluid intelligence
and crystallized intelligence, it shows a continue growth for crystallized
intelligence from adolescence to older adulthood and reached the peak at the
age group of 40-50. However, the fluid intelligence shows a peak at the
adolescence then keeps declining until old adulthood.
Applying Horn’s theory, fluid
intelligence is the biological capacity for a person to obtain knowledge. When
the brain grows older and becomes deteriorate, fluid intelligence declines
accordingly. Crystallized intelligence is influenced and shaped by the external
environment, it is not surprising to find that when a person grows and
experiences more, the crystallized intelligence increases. However, the general
intelligence is measured by the combination of two, the increment in the
crystallized intelligence is offset by the decrement in fluid intelligence.
From the cross-sectional manner, it is
easy to conclude that the general intelligence of an individual decline with
age. But part of the abilities are still active especially when the adult reach
it midlife and have cumulated various experience, education and acculturation.
However, if the longitudinal study is used, it shows a different picture. It
shows a continual growth of intelligence in the midlife, and a slight decline
after 50. (Owen, 1966; Cunningham & Owen, 1983, cited in Hoyer et al, 2003)
The difference is due to the
methodology used, the methodology of cross-sectional studies is to examine
separate age groups of people at the same time, because of the cohort effect,
this can only measure the developmental difference rather than the real change
of a person. It tends to show different peak time in studies conducted in
different chronological years.
However, longitudinal studies examine
a group of person in a long time. It can reflect how a person develops in his
life. Schwartzman and his colleagues (1987) examined a group of 260 men with
similar educational background. They first took tests during the World War II,
and retested 40 years later. Presumably the comparison of the two tests can
really show the developmental change of the individuals.
It reflected that the verbal abilities
were undergoing improvements, while the non-verbal ones were declining. It also
showed that the men in the later years can still have high score with double
time allowed. And it is only a slight decline under the normal time condition.
It suggested that the slow response of older adult might performance in older
adult but not as a big influence as it was thought to be.
The study also suggested that
individual difference is stable over the 40 years, high score is more related
to the education level rather than affected by the age factor, self-reported
activity levels and personal lifestyle differences were related to test scores
at both time of testing.
The result can be explained by Horn’s
theory, that part of intelligence is affected by accumulated educational level
and experiences. While daily lifestyle and habits varies from person to person,
yet it is largely influenced by the environment that brought the person up.
A large scale study Deattle
Longitudinal Study (SLS) began in 1956, consisted of 6 cross-sectional studies
and 1 longitudinal study covering 35 years, which is conducted by Schaie and
his associates (2001) use the sequential research design to examine 500
participants aged between 22 and 70 with primary mental ability tests. Along
with new groups of individual, they were retested at 7-years intervals until
1998. A total of more than 5,000 individual were tested in the SLS.
The independent cross-sectional data
shows a general decline of intelligence level, however, when comparing the data
in different time intervals, it shows a shifting tendency with later data shows
peaks at a later age and the poorest performance also at a later age.
This can be explained by its own
longitudinal study, which suggested that individual has gained higher or stable
scores in their mid-adult years, and only a slight decline after 60.
Of course, there would be factors
affecting the adequacy and accuracy of the longitudinal studies, like cohort
effects, selective dropout, health problem… etc. However, it is clear that
individual could be more intelligent in their old age with acculturation and
accumulated education and experience. For the later generation, they have more
opportunities to receive better education, and that would affect them to have a
higher score than their previous generation at the same age. That is why
cross-sectional studies at different years show a different level of
intelligence.
One thing that we have to bear in
mind, is that the crystallized intelligence which tends to reach its peak at
the midlife, is more likely to be the practical intelligence, because it
reflects the everyday affair. But still there are lots of other practical
intelligences that would seriously affect job performance were not
investigated.
Psychometric intelligence test could
be an indicator to the intelligence level, however it is useless to define
unusual word that only appears in an IQ test. Also the IQ tests are putting
elderly in disadvantages, for examples, the time limits is obviously
influential to older adult in doing a test, they would be less motivated and
more anxious in taking test. Besides, the original goal of intelligence tests
was for academic use in schools, but not the real-world functioning.
(Sternberg, 1995) Thus, the discussion about developmental changes in the
middle adult years to the older adult years based on the intelligence tests
designed for children to adolescence can only reflects parts of the reality.
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