PSY1EFP Lecture Notes - Lecture 12: Wechsler Adult Intelligence Scale, David Wechsler, Flynn Effect
18 Jun 2018
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EFP Lecture 12 Session 1 – Memory, Thinking and Intelligence (5)
How do we understand intelligence? Ways to look smarter
Intelligence: the ability to use knowledge to reason, make
decisions, make sense of events, solve problems, understand
complex ideas, learn quickly, and adapt to environmental
challenges
Psychologists consider two questions when measuring
intelligence.
How do knowledge and its applications in everyday life
translate into intelligence?
How much is intelligence determined by genes and how much
by environment?
Intelligence is measured with standardized tests
The psychometric approach to measuring intelligence focuses on how people perform on standardized tests.
Some psychometric tests focus on achievement; other psychometric tests focus on aptitude.
Binet proposed that intelligence is best understood as a collection of high-level mental processes.
Psychometric tests of general intelligence include the Stanford-Binet test, which measures intelligence using the
intelligence quotient, or IQ score.
Intelligence Is Measured with Standardized Tests
In 1939, the psychologist David Wechsler developed an intelligence test for adults.
Wechsler was dissatisfied with various features of the Stanford-Binet scale, including its reliance on verbal information
and its assessment of intelligence by a single score.
The Wechsler Adult Intelligence Scale has four indices. Verbal Comprehension Perceptual Reasoning Working
Memory Processing Speed
Intelligence Quotient
Intelligence quotient (IQ): an index of intelligence computed by dividing a child’s estimated mental age by the child’s
chronological age, then multiplying this number by 100, developed by Wilhelm Stern
IQ in the adult range is measured in comparison with the average adult and not with adults at different ages.
Across large groups of people, the distribution of IQ scores forms a bell curve, or normal distribution; most people are
close to the average.
Extremes of Intelligence
A valid intelligence test divides two groups of people into two extremes: the intellectually disabled (IQ 70) and
individuals with high intelligence (i.e. the gifted) (IQ 135). These two groups are significantly different.
High Intelligence
• Contrary to popular belief, people with high intelligence test scores tend to be healthy, well adjusted, and unusually
successful academically
The spectrum of intellectual disability
• Intellectually disabled individuals required constant supervision a few decades ago, but with a supportive family
environment and special education they can now care for themselves.
The Flynn Effect & Why does the Flynn effect occur?
In the past 60 years, intelligence scores have risen steadily by an average of 27 points. This phenomenon is known as
the Flynn effect
Flynn (1994, 1999) favours environmental explanations for the increase in test scores. In some cases IQ gains are
highly correlated to increased years spent in formal education. Again, several scholars point at the increase in culture-
free tests as evidence against an educational cause.
The Brand hypothesis: Societal changes causing IQ gains? Better nutrition a cause of IQ gains?
Still a mystery, but it seems to be slowing if not stopping altogether.
General intelligence involves multiple components
An early line of research examined the correlations among intelligence test items using factor analysis. In this
statistical technique, items similar to one another are clustered, and the clusters are referred to as factors.
Charles Spearman found that most intelligence test items tended to cluster as one factor.
Spearman viewed general intelligence, or g, as a factor that contributes to performance on any intellectual task.
find more resources at oneclass.com
find more resources at oneclass.com
General intelligence (g): the idea that one general factor underlies intelligence
Fluid versus crystallized intelligence
Cattell (1971) proposed that g consists of two types of intelligence.
Fluid intelligence: intelligence that reflects the ability to process information, particularly in novel or complex
circumstances
Crystallized intelligence: intelligence that reflects both the knowledge one acquires through experience and the ability
to use that knowledge
Distinguishing between fluid intelligence and crystallized intelligence is somewhat analogous to distinguishing
between working memory (more like fluid intelligence) and long-term memory (more like crystallized intelligence).
Crystallized intelligence grows steadily throughout the adult years, while fluid intelligence declines steadily
The importance of g
Research has shown that g influences important life outcomes by, for example, predicting performance in school and
at work. Low g is related to early death from causes including heart disease, diabetes, stroke, Alzheimer’s disease,
traffic accidents, and drownings. Although most psychologists agree that some form of g exists, they also recognize
that intelligence comes in various forms.
Intelligence is related to cognitive performance
Galton believed that intelligence was related to the speed of neural responses and the sensitivity of the
sensory/perceptual systems, and he speculated that intelligent people have larger, more efficient brains.
Other psychologists believe intelligence is supported by low level cognitive processes, such as mental processing,
working memory, and attention.
People who score higher on intelligence tests respond more quickly and consistently on reaction time tests.
A test of simple reaction time might require a person to press a computer key as quickly as possible whenever a
stimulus appears on the screen.
Scores on intelligence tests are related even more strongly to this test of choice reaction time.
Working memory
General intelligence scores are closely related to working memory but not identical.
Studies differentiate between simple tests of memory span and memory tests that require some form of secondary
processing.
Memory tests that have dual components show a strong relation between working memory and general intelligence.
The link between working memory and general intelligence may be attention, or the ability to pay attention
Genes and environment influence intelligence
Even if intelligence has a genetic component, the way intelligence becomes expressed is affected by various
situational circumstances. For example, the capacity for having a large vocabulary is considerably heritable, but every
word in a person’s vocabulary is learned in an environment. Instead of seeking to demonstrate whether nature or
nurture is the more important factor, psychologists try to identify how each of these crucial factors contributes to
intelligence.
Genetics Factors
Numerous behavioural genetics studies have made clear that genes help determine intelligence—but the extent to
which genes do so is difficult to determine.
Behavioural geneticists study the genetic basis of behaviours and traits such as intelligence; they use twin and
adoption studies to estimate the extent to which particular traits are heritable.
Even when raised apart, twins who have inherited an advantage might receive some social multiplier, an
environmental factor or an entire environment, that increases what might have started as a small advantage.
Suppose the twins have inherited a higher than average verbal ability? Adults who notice this ability might read to
them more often and give them more books.
Environmental Factors
Many environmental influences affect human intelligence.
Prenatal factors - Parents’ nutrition and intake of substances, including toxins
Postnatal factors - Family, social class, education, nutrition, cultural beliefs about the value of education, and the
person’s intake of substances, including toxins
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Efp lecture 12 session 1 memory, thinking and intelligence (5) Intelligence: the ability to use knowledge to reason, make decisions, make sense of events, solve problems, understand complex ideas, learn quickly, and adapt to environmental challenges. The psychometric approach to measuring intelligence focuses on how people perform on standardized tests. Some psychometric tests focus on achievement; other psychometric tests focus on aptitude. Binet proposed that intelligence is best understood as a collection of high-level mental processes. Psychometric tests of general intelligence include the stanford-binet test, which measures intelligence using the intelligence quotient, or iq score. In 1939, the psychologist david wechsler developed an intelligence test for adults. Wechsler was dissatisfied with various features of the stanford-binet scale, including its reliance on verbal information and its assessment of intelligence by a single score. The wechsler adult intelligence scale has four indices.
