Intelligence and IQ Testing - Chapter 9
Page 364
• Karl Fredrich Gauss is a great German mathematician was the first to come up with
the concept of the "bell curve"
• Today, we sometimes refer to the bell curve as the "Gaussian distribution"
• This curve describes how people differ in their scores on intelligence tests
• Gauss was a genius, with an IQ ("Intelligence quotient") of 180+
• The average person's IQ is typically somewhere around 100
• Gauss was a child prodigy
• By the time he was 2 years old, he had taught himself reading and basic arithmetic
• At age 3, he caught a calculation error that his father had made when adding up his
family's finances
What is Intelligence: Definitional Confusion (Page 366)
• One of the problems that makes psychology so challenging is the lack of clear-cut
definitions for many of its concepts
• Even today, psychologists can't agree on the precise definition of intelligence
Special Considerations in Interpreting Intelligence Research
• Emotional reasoning: The tendency to judge the validity of an idea by our
emotional reactions to it
IntelligenceAs Sensory Capacity: Out of Sight, Out of Mind
• Sir Francis Galton was also a child prodigy, and learned to read at about age 2
• Galton invented techniques that are still in use today: the method of studying twins
to determine the genetic bases of traits, the correlation as a measure of statistical
association, and criminal fingerprinting
• Galton claimed that intelligence is the by-product of sensory capacity
• According to him, most knowledge first comes through the senses (especially vision and hearing)
• He assumed that people with superior sensory capacities (like better eyesight)
should acquire more knowledge than other people
IntelligenceAs Abstract Thinking
• Early in the last century, the French government wanted to find a way to identify
children in need of special educational assistance
• In 1904, the Minister of Public Instruction in Paris tapped two individuals (Alfred
Binet and Henri Simon) to develop a psychological test that would identify students
who might require additional instruction in certain scholastic abilities
• Abstract thinking: Capacity to understand hypothetical concepts
That Controversial Little Letter: G
• Developed by Charles Spearman - G, or general intelligence: hypothetical factor
that accounts for overall differences in intellect among people
• G implies that some people are smarter than others
• Spearman also proposed the existence of a factor called s or specific abilities that
refer to a particular ability level in a narrow domain
• Even if we're really smart (high in overall g), we might flunk an item because we
have a specific deficiency when it comes to spatial problems
• ^ That deficiency may mean that we're inherently not adept at spatial tasks or that
we haven't had much experience with them
Fluid and Crystallised Intelligence
• Later researchers found that Spearman's g wasn't as uniform as he'd believed
• They discovered that some intelligence test items relate more highly to each other
than do other items: These items form clumps of related abilities
• Among these investigators were Raymond Cattell and John Horn who distinguished
fluid from crystallised intelligence
• Fluid intelligence: The capacity to learn new ways of solving problems. For
example, we rely on fluid intelligence the first time we try to operate a type of
vehicle we've never driven • Crystallized intelligence: The accumulated knowledge of the world we acquire
over time. For example, we rely on our crystallised intelligence to answer questions
such as "what's the capital of Italy"
• According to Cattell and Horn, knowledge from newly learned tasks "flows" into
our long-term memories, "crystallizing" into lasting knowledge
• Fluid abilities are more likely to decline with age than are crystallized abilities
• Some researchers have found that crystallized abilities increase with age
• Fluid abilities ar emore highly related to g than crystallized abilities
Multiple Intelligences: Different Ways of Being Smart
• Since the 1930s, some psychologists have argued for the existence of multiple
intelligences: different domains of intellectual skill
• According to them, the concept of g is wrong, or at least incomplete
• These psychologists maintain that we can't simply say that Sally is smarter than
Bill, because there are many ways of being smart
• Howard Gardner's theory of multiple intelligences has been enormously influential
in educational practice and theory over the past two decades
• According to Gardner, there are numerous "frames of mind," or different ways of
thinking about the world
• Each frame of mind is a different and fully independent intelligence in it's own right
• Gardner outlined a number of criteria for determining whether a mental ability is a
seperate intelligence
• Gardner argued that different intelligences should be especially pronounced in
people with exceptional talents
• Gardner also suggested that different intelligences should make sense from an
evolutionary standpoint: They should help organisms survive or make it easier for
them to meet future mates
• Gardner proposed eight different intelligences ranging from linguistic and spatial to
musical and interpersonal
• He's also proposed the existence of a ninth intelligence, called existential
intelligence: the ability to grasp deep philosophical ideas, like the meaning of life
Howard Gardner's Multiple Intelligences:
1. Linguistic: Speaks and writes well (translator, editor) 2. Logico-mathematical: Uses logic and mathematical skills to solve problems
(engineer, scientist)
3. Spatial: Think and reason about objects in three-dimensional space (architects,
artists)
4. Musical: Perform, understand, and enjoy music (musician, teacher)
5. Bodily-kinesthetic: Manipulate the body in sports, dance, or otehr physical
endeavours (athletes, dancers)
6. Interpersonal: Understand and interact effectively with others (sales, teacher,
counsellor)
7. Intrapersonal: Understand and possess insight into self (philosopher, prophet)
8. Naturalistic: Recognise, identify, and understand animals, plants, and other living
things
• All researchers agree with Gardner that we vary in our intellectual strengths and
weaknesses
• However, much of Gardner's model is difficult and hard to test
• According to Gardner's criteria, there should probably also be "humour" and
"memory" intelligences
The Triarchic Model
• Robert Sternberg has argued thatt here's more to intelligence than g
• Sternberg's triarchic model posits the existence of three largely distinct
intelligences:
1. Analytical intelligence: The ability to reason logically, also called "book smarts"
and is closely related to g
2. Practical intelligence: Also called "tacit intelligence"; the ability to solve real-
world problems, especially those involving other people. It's the kind of smarts we
need to figure out how to get ahead on the job. Practical intelligence also relates to
what some researchers call "social intelligence," or the capacity to understand
others
3. Creative intelligence: Also called "creativity"; our ability to come up with novel
and effective answers to questions. It's the kind of intelligence we need tovfind new
and effective solutions to problems, like composing an emotionall moving poem or
exquisite piece of music. • Sternberg argues that practical and creative intelligences predict outcomes, like job
performance, and analytical intelligence doesn't
How AwareAre We of Our Intellectual Limitations
• Recent evidence suggests that people with poor cognitive skills are especially likely
to overestimate their intellectual abilities, a phenomenon called the double curse of
incompetence
• This curse may explain why some people perform poorly in school and on the job,
even though they're convinced they're performing well
• Not knowing our intellectual limitations may render us overconfident in our
knowledge
• We shouldn't necessarily trust our intuitions about how well we've performed
• If our abilities in a domain are weak, we're often the last to know about it
• Metacognition: knowledge of our own knowledge
• People with poor metacognitive skills in a given domain may overestimate their
performance because they don't know what they don't know
Brain Size and Intelligence in Humans
• Several studies demonstrate that brain size is linked to intelligence
• Intelligent brains take longer to mature than others
Intelligence and Memory
• Intelligence also bears an intimate connection to memory capacity
The Location of Intelligence
• Intelligence is more localized to certain areas of the cortex than others
• One group of investigators administered a number of reasoning tasks that are highly
"g-loaded" - they're substantially related to general intelligence
• These tasks all activated the same area: the prefrontal cortex Pulling ItAll Together
• Intelligence is related to efficiency or speed of information processing
• People who are quick thinkers tend to be especially intelligent
• Intelligence is more than quickness of thinking
• The capacity to recall short-term information is related to intelligence
Two More Controversial Letters: IQ
• German psychologist Wilhelm Stern invented the formula for the intelligence
quotient, which is known as IQ
• Stern's formula for calculating IQ was simple: Divide mental age by chronological
age and multiply that number by 100
• Mental age is the age corresponding to the average person's performance on an
intelligence test. For example:A girl who takes an IQ test and does as well as the
average 6-year-old has a mental age of 6
Deviation IQ: Rescuing Adults from Declining Intelligence
• Stern's formula contains a critical flaw: Mental age scores increase progressively in
childhood, but start to level out at around age 16
• Once we hit 16 or so, our performance on IQ test items doesn't increase by much
• Because our mental age levels off but our chronological age increases with time,
Stern's formula would result in everyone's IQ getting lower and lower as they get
older
• That's why almost all modern intelligence researchers rely on a statistic called
deviation IQ when calculating for adults
• The deviation IQ expresses each person's IQ relative to his or her same-aged peers
• An average IQ of 100 means that a person's IQ is exactly typical of people his age
• The deviation IQ gets rid of the problem posed by Stern's formula, because it
doesn't result in IQ decreasing after age 16
The Eugenics Movement: Misuses andAbuses of IQ Testing
• Eugenics: Movement in the early twentieth century to improve a population's genetic stock by encouraging those with good genes to reproduce, preventing those
with bad genes from reproducing
• Eugenics came to be associated with at least two disturbing practices
• Beginning in the 1920s, both the U.S. Congress and Canadian House of Commons
passed laws designed to restrict immigration from other countries supposedly
marked by low intelligence, especially those in eastern and southern Europe
• In fact, a hierachy of immigration status was constructed to encourage those of
higher status into the countries
• Many provinces in Canada passed laws requiring the sterilization of low-IQ
individuals
• The surgeons performing these sterilizations tricked their patients into believing
they were undergoing emergency appendectomies (removal of the appendix)
• The assumption behind mandatory sterilization was that IQ was genetically
influenced, so preventing low-IQ individuals from reproducing would halt the
supposed deterioration of the population's intelligence
• Avariety of other troubling practices were perpetrated on individuals in the U.S and
Europe as a result of early IQ testing
• In 1917, psychologist Robert Yerkes joined forces with the U.S.Army to launch an
IQ testing program that helped determine who would serve as officers and who
would serve on the front lines in battle during the First World War
• Not surprisingly, recent immigrants and underprivledged minorities were the most
frequently relegated to hazardous duty
IQ Testing Today
Commonly Used Adult IQ Tests
• The Wechsler Adult Intelligence Scale (WAIS) is the most widely used IQ test to
assess intellignece in adults
• WAIS is now in it's 4th version
• Developed by David Wechsler
• The WAIS-IV consists of 15 "subtests," or specific tasks, designed to assess mental
abilities such as vocabulary, arithmetic, spatial ability, reasoning about proverbs,
and general knowledge about the world
• The WAIS-IV yields several major scores: (1) an overall IQ score; and specific
subscale scores for (2) verbal comprehension, (3) perceptual reasoning, (4) working memory, and (5) processing speed
Commonly Used Childhood IQ Tests
• Two widely used IQ tests for children
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