Unit 11-Testing & Individual Differences (Intelligence)

Does each of us have an inborn general mental capacity (intelligence), and can we quantify this capacity as a mental number (IQ—intelligence quotient?)
School boards, courts and scientists debate the use and fairness of tests that attempt to assess people’s mental abilities and assign them a score
There are a variety of mental gifts and the recipe for high achievement in any field blends talent and hard work. –intelligence can be defined in many ways and is socially constructed by its meaning to different cultures

What is intelligence?
Intelligence is the ability to learn from experience, solve problems and use knowledge to adapt to new situations
Intelligence tests are a method for assessing an individual’s mental aptitudes and comparing them with others using numerical scores
Intelligence is a concept, not a thing. When we refer to someone’s IQ as if it were fixed (like someone’s height or shoe size), we commit a reasoning errors called reification (viewing an abstract, immaterial concept as if it were a concrete thing)

Is Intelligence one general ability or several spatial abilities?
Charles Spearman believed we have one general intelligence (g)—people often have special abilities that stand out over others
He helped develop factor analysis (a statistical procedure that identifies clusters of related items)
Those who score high in one area (verbal intelligence) typically score higher than average in other areas (spatial or reasoning ability)

Controversies of general mental intelligence
One of Spearman’s early opponents was L.L. Thurstone:
Is intelligence a single ranking ability or several combined?
Thurstone gave 56 different tests to people and mathematically identified seven clusters of primary mental abilities
Thurstone did not rank people on a single scale of general aptitude, but other investigators who studied the profiles of people who Thurstone tested, there was some evidence of a g factor
Several distinct abilities tend to cluster together and correlate enough to define a small general intelligence factor
With modern neuroscience techniques, can we locate and measure intelligence within the brain?
Intelligence: Ability or Abilities?
Can we define intelligence by one primary factor?
Can a body builder who is elite in lifting be a competitive figure skater?--NO
You may speculate that diverse abilities represent different kinds of intelligences. How can you test this idea?
Measure different types of intelligence—multiple intelligences (creative, emotional, spatial, etc…)

Theories of Multiple Intelligence
Howard Gardner views intelligence as multiple abilities that come in packages—views this in people with diminished or exceptional abilities
Brain damage may destroy one ability of intelligence, but leave others intact
People with savant syndrome (a condition in which a person otherwise limited in mental ability has an exceptional specific skill—computing or drawing)
Some will score low on intelligence tests, but have other brilliant areas
4 in 5 people with savant syndrome are males, and many have autism
Kim Peek (a savant, but did not have autism) inspired the movie Rain Man
He learned maps from the front of phone books and could give GPS like directions within any major US city
But he could not button his clothes and control his voice in formal places

Gardner’s Eight Intelligences

Gardner argues that we do not have an intelligence, but multiple intelligences (8)—see chart
Gardner (1998) has speculated a 9th possible intelligence—existential intelligence (the ability to “ponder large questions about life, death, and existence)
People with high intelligence scores are predicted to have graduate school and career success, but not will not always predict success once a person gets there
It takes hard work and talent (multiple skills and abilities)
Anders Ericsson—10 year rule---it takes 10 years of intense, daily practice to be an expert in a field or ability
Gardener’s theory of multiple intelligences is largely based on case study research—the results have been criticized to not be generalizable to the population at large—some say his theory borders on philosophy rather than science
Unable to produce a valid and reliable test to assess whether people have multiple intelligences or which type of intelligence people might have

Robert Sternberg’s Three Intelligences

Agreed there is more to success than traditional general intelligence—agreed with Gardner’s theory of multiple intelligences—he just proposed three instead of 8
Analytical (academic problem-solving) intelligence
Assessed by intelligence tests—have a single right answer
Creative Intelligence
Is demonstrated in reacting to novel (new) situations and generating novel (new/fresh) ideas
Practice Intelligence
Required for everyday tasks with multiple solutions
“Street smarts”—multiple skills in a profession to be successful

Comparing the theories of intelligence

Emotional Intelligence

Edward Thorndike proposed another distinction from academic intelligence is social intelligence in 1920
Social intelligence = the knowledge involved in interpreting social situations and managing oneself successfully
Some have explored the difficulty that some rationally smart people have in processing and managing social information = emotional intelligence –John Mayer, Peter Salovey and David Caruso are the main researchers
Developed a test to assess the four emotional intelligence components:
The ability to perceive emotion (to recognize emotion in faces, music, and stories)
The ability to understand emotions (to predict them and how they change and blend)
The ability to manage emotions (to know how to express them in varied situations)
The ability to use emotions to enable adaptive or creative thinking
Suggest people who are emotionally in tune with others often succeed in career, marriage and parenting situations where academically smarter, but emotionally less intelligent people often fail
EQ Criticisms:
Howard Gardner (1999) is concerned that emotional intelligence stretches the concept of intelligence too far
We need to respect emotional sensitivity, creativity and motivation as important, but different

Creativity & Intelligence

Creativity is the ability to produce ideas that are both novel and valuable. It correlates somewhat with intelligence.
Expertise: A well-developed knowledge base.
Imaginative Thinking: The ability to see things in novel ways.
Adventuresome Personality: A personality that seeks new experiences rather than following the pack.
Intrinsic Motivation: A motivation to be creative from within.
A Creative Environment: A creative and supportive environment allows creativity to bloom.

Is Intelligence Neurologically Measurable?

Studies have revealed correlations of about +.33 between brain size (adjusted for body size) and intelligence scores—especially in the frontal and parietal lobes
Einstein’s brain was 15% larger in the parietal lobe’s lower region---a center for processing mathematical and spatial information
Highly educated people die with more synapses (17% more in one study) than less-educated people
As adults age, brain size and nonverbal intelligence test scores fall
Cause could be differing genes, environment, nutrition and a combination of these or something else
Psychologist Richard Haier and his team correlated intelligence scores with scans that measure the volume of gray matter (neural cell bodies) and white matter (axons and dendrites) of 47 adult volunteers
Higher intelligence scores were linked with more gray matter in areas known to be involved in memory, attention and language

Brain Function

As people contemplate a variety of questions (from an IQ test), a frontal lobe area just above the outer edge of the eyebrows becomes especially active—left brain for verbal questions, both sides for spatial questions
Earl Hunt (1983) found that verbal intelligence scores are predictable from the speed with which people retrieve information from memory (recognizing the sink and wink are different words)
The correlation between intelligence scores and the speed of taking in perceptual information are between +.3 to +.5
A typical experiment flashes an in complete stimulus—like the image—then a masking image (another image that overrides the lingering afterimage of the incomplete stimulus)
Researchers then ask whether the long side appeared on the right or left
Those who perceive very quickly—tend to have higher intelligence scores
Neurological Speed
Highly intelligent people register a simple stimulus more quickly and with greater complexity as noted in repeated studies
Others suggest faster cognitive processing may allow more information to be acquired = higher IQ scores

Assessing Intelligence

Francis Galton measured “natural ability”—attempted to measure intelligence through the inheritance of reputation and genius
Psychologists define intelligence testing as a method for assessing an individual’s mental aptitudes and comparing them with others using numerical scores.

Alfred Binet: Predicting School Achievement

Modern intelligence testing began in early 1900s in France when they required by law that all children attend school—this test allowed for students with special needs to be identified
To minimize bias, in 1904 Alfred Binet and Theodore Simon researched how to construct such a test
Their goal was to measure each child’s mental age—the level of performance typically associated with a certain chronological age
Average 9 year old has a mental age of 9
They theorized that mental aptitude, like athletic aptitude, is a general capacity that shows up in a variety of ways
Binet & Simon made no assumptions concerning why a particular child was slow, average or intelligent—feared this would lead to labeling children and limit their opportunities

Lewis Terman: The Innate IQ

Stanford University professor Lewis Terman adapted Binet’s test for use as a numerical measure of inherited intelligence
Stanford-Binet test—widely used American revision by Lewis Terman of Binet’s original intelligence test
German psychologist William Stern derived the intelligence quotient (IQ)formula
Lewis Terman then used the formula with his Stanford-Binet intelligence test
A person’s mental age divided by chronological age and multiplied by 100
IQ = 17/17 x 100 (IQ =100) or 19/17 x 100 (IQ = 112)
A 8 year old has a mental age of 10, what is her IQ? --125
A 12 year old has the mental age of 9, what is his IQ? --75
A boy has the mental age of 10 and an IQ of 200, how old is he?--- 5

Problems with IQ--

Worked well for children, but not for adults—a 60 year old who does as well on a test as a 20 year old would only have an IQ of 33
Today current intelligence tests represent the test taker’s performance relative to the average performance of others the same age
Most fall between 85-115; normal = 100

Modern Tests of Mental Abilities

Achievement tests = intended to reflect what you have learned ( driver’s license exams, AP tests)
Assess current performance
Aptitude tests = intended to predict your ability to learn a new skills (SAT (Scholastic Aptitude Test/ACT (American College Test)
Assess future performance
Most tests whether labeled achievement or aptitude tests assess both ability and your development

David Wechsler

Psychologist David Wechsler created the most widely used intelligence test—the Wechsler Adult Intelligence Scale (WAIS)—with a version for school-aged children (the Wechsler Intelligence Scale for Children –WISC) and another for preschool children
WAIS = 11 subtests broken into verbal and performance areas (see visual)
The test produces an overall intelligence score and separate scores for verbal comprehension, perceptual organization, working memory and processing speed
Can provide clues to cognitive strengths & weaknesses that teachers, counselors, social workers or therapists can build upon

Principles of Test Construction

To be widely accepted, psychological tests must be standardized, reliable and valid—the Stanford-Binet & Wechsler tests meet these requirements

Standardization

To evaluate test performance, psychologists need a basis for comparing it with others’ performance—when you give the test to a representative sample of people, then the score can be compared with the sample’s scores to determine the tester’s position relative to others
This process of defining meaningful scores relative to a pretested group = standardization
Standardizing involves testing in conditions that are similar as possible (taking standardized tests in the same school, same time, same test, etc…)

Normal Curve

Group members’ scores typically are distributed in a bell-shaped pattern that forms the normal curve
Norming = taking the scores from the same test and graphing them. With a large sample of data, the normal curve usually results
On intelligence tests—the midpoint (average score) = 100
Moving out from 100—toward either extreme, we find fewer & fewer people

Flynn Effect

Intelligence test performance has been improving across the globe
In honor of New Zealand researcher James Flynn = Flynn effect
What has caused this?
Greater test sophistication? Better nutrition? More education? More stimulating environments? Less childhood disease? Smaller families and more parental involvement?

Reliability

Reliability=yielding dependent consistent scores
To check a test’s reliability, researchers retest people—they may use the same test or split the test in half and see whether odd-question scores and even-question scores agree (are similar)
If the two scores generally agree/correlate, the test is reliable
The higher the correlation between the test-retest or split-half scores, the higher the test’s reliability
The Stanford-Binet, WAIS, WISC—all have reliability of about +.9 (really high)

Validity

High test reliability does not ensure a test’s validity—the extent to which the test actually measures or predicts what it promises
Some tests have content validity—the test measures the pertinent behavior (what they are supposed to measure)- (criterion)—a road test for a driver’s license—will test similar conditions a real-life driver would experience; unit tests in AP Psych—assesses your mastery of the unit’s material
We expect intelligence tests to have predictive validity—should predict the behavior/criterion of future performance (to some extent, they do)
Driver’s tests should predict good driving habits; the ACT/SAT should predict college performance
The predictive power of elementary age aptitude tests are fairly strong, but then weaken after middle school
The SAT predictive validity = less than +.5 to predict first-year college students’ grades

Dynamics of Intelligence

How stable are intelligence scores over the life span?
Are individuals on the two extremes of intelligence all that different?

Stability or Change?

Developmental researchers have observed everything about infants to try to detect indicators of infants’ later intelligence—none have determined any useful predictions of intelligence scores at later ages
Except for extremely impaired or very intelligent children, casual observation and intelligence tests before the age of 3 only modestly predict children’s future aptitudes
By age 4, children’s performance on intelligence tests begins to predict their adolescent and adult scores
By age 7, the scores stabilize—the consistency of the scores over time increases with the age of the child
When Ian Deary and his colleagues retest 80 year old Scottish citizens, using an intelligence test they had taken as 11 year olds, their score across seven decades correlated +.66 (scatterplot)
Those who remained mentally active were more likely to live longer and have a smaller incidence of Alzheimer’s disease

Extremes of Intelligence

One way to compare the validity/significance of any test is to compare people who score at the two extremes of a normal curve
Low Extreme
Those whose intelligence test scores fall at 70 or below
To be labeled as having an intellectual disability –formerly referred to as mental retardation—a child must have both a low test score and difficulty adapting to the normal demands of independent living (1% of the population meets both—males outnumber females by 50%
Most people with intellectual disabilities can, with support, live in mainstream society
Intellectual disabilities sometimes have a physical cause—Down syndrome—having an extra chromosome 21 in the person’s genetic makeup
Parents used to be told to separate themselves permanently from their impaired child before they became attached
Now times have changed and many encourage people to live in their own communities as normally as their functioning permits, some live in a group home and/or are mainstreamed into the classroom if they have a mild intellectual disability
High Extreme
Those whose intelligence test scores fall at 135 or above
Children with extraordinary academic gifts are sometimes more isolated, introverted and in their own worlds, but most thrive and live healthy, well-adjusted lives
Tracking “gifted children” into separate classrooms to challenge them in a different learning environment creates a self-fulfilling prophecy—those who are “ungifted” may be influenced to improve their skills and become gifted
We need to provide appropriate developmental placement suited to each child’s talents, we can promote equity and excellence for all

Genetic & Environmental Influences on Intelligence

We may inherit different traits from our parents, but not all traits will manifest itself into each child—about 50% of intelligence is heritable
Heritability pertains to why people differ from one another
Genetic influences
People who share the same genes also share comparable mental abilities (see chart)
Intelligence tests of identical twins raised together are virtually as similar as those of the same person taking the same test twice
Brain scans reveal identical twins have very similar gray matter volume, and their brains are virtually the same in areas associated with verbal and spatial intelligence
Intelligence appears to be polygenetic—many genes seem to be involved with each gene accounting for much less than 1% of intelligence variations
Adoption influences
Studies show that adoption enhances the intelligence scores of mistreated or neglected children
During childhood, intelligence scores of adoptive siblings correlate modestly
Over time, adoptive children accumulate experience in their differing adoptive families
Mental similarities between adopted children & their adoptive families wane with age—until the correlation reaches 0 by adulthood
Genetic influences—not environmental ones—become more apparent as we accumulate life experiences
Adopted children’s intelligence scores over time become more like those of their biological parents (see chart)
Environmental Influences
Genes and environment work together---genes shape the experiences that shape us

Early Intervention Effects