CHAPTER 11: INTELLIGENCE

• Introduction• Intelligence testing• Theories of intelligence• Heredity and environment• Size does matter!

Introduction

• According to Sternberg (2004, p. 472), intelligence involves “the capacity to learn from experience and adaptation to one’s environment.” • We need to pay attention to cultural differences.• What is needed to adapt successfully in one

environment may be very different from what is required in another environment.

• Individualistic vs. collectivistic.

In Zimbabwe, the word for intelligence is ngware. What does this mean?

• a) Be able to find your way in a new environment

• b) Do well in school• c) Be able to play a musical instrument• d) Be careful and prudent in social

relationships• e) Be independent

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Emotional Intelligence

• Defined as “the ability to monitor one’s own and others’ emotions, to discriminate among them, and to use the information to guide one’s thinking and actions.”

• Most early research on emotional intelligence made use of self-report questionnaire measures.• Emotional Intelligence Inventory

• Davies, Stankov, and Roberts (1998) carried out several studies to find out what is being measured by questionnaire measures of emotional intelligence.• They found that measures of emotional intelligence were

unrelated to intelligence assessed by IQ tests.

Emotional Intelligence• Mayer, Salovey, and Caruso (2002) developed an

Emotional Intelligence Test (MSCEIT) based on the notion that that four main abilities underlie emotional intelligence:• Perceiving emotions: identification of emotion in oneself and in

others (e.g., identifying facial emotions).• Using emotions: facilitating thought and action through

experiencing the optimal emotion. • Understanding emotions: the ability to comprehend the

language of emotion and to make sense of complicated relationships among emotions.

• Managing emotions: regulation of emotion in oneself and others.

Emotional Intelligence

• Findings from use of the MSCEIT:• Small to moderate correlations with intelligence and

personality factors.• It predicted deviant behavior in male adolescents.• High scores were rated as more positive for

personality qualities.• Heterosexual couples with high scores were happier

than those with low scores.• Employees with high scores were rated as being

better (easy to deal with, sociable, leaders, more promotions).

Evaluation

• Emotional intelligence is of real importance and deserves to be the focus of research.

• Traditional approaches to intelligence are somewhat narrow, and an emphasis on emotional intelligence serves to broaden intelligence research.

• The MSCEIT is a reasonably promising measure of emotional intelligence.

• Most self-report questionnaire measures of emotional intelligence are seriously deficient, and assess mainly well-established personality dimensions.

• There is little evidence that any measures of emotional intelligence predict job performance or success over and above that predicted by pre-existing ability and personality measures.

• More research is needed to establish that emotional intelligence is actually an important type of intelligence.

Practical Importance

• There is convincing evidence that intelligence is very important in everyday life.

• For example, job performance and academic achievement among students are both moderately well predicted by intelligence or IQ (Mackintosh, 1998).

• Hunter and Hunter (1984) considered over 32,000 workers performing 515 different jobs. • They identified five levels of job complexity.• The average correlations between intelligence and job performance

were as follows: +.58 for professional jobs, +.56 for complex technical jobs, +.51 for medium-complexity jobs, +.40 for semi-skilled jobs, and +.23 for unskilled jobs.

Practical Importance• Hunter (1983) studied four very large samples of military

personnel undergoing job training programs.• In all samples, intelligence strongly predicted training

performance and specific aptitude or ability scores.• Why is there is a strong association between intelligence and

job performance?• There is a moderate correlation between intelligence and

socioeconomic status (Mackintosh, 1998).• Murray (1998): siblings with higher intelligence had more

prestigious jobs and higher incomes. • Hunter and Schmidt (e.g., 1996) argued that the ability to learn

rapidly is of crucial importance in most jobs, and learning ability is determined by intelligence.

Health and Longevity

• Individual differences in intelligence also predict health and longevity (Gottfredson & Deary, 2004).

• Whalley and Deary (2001) found that individuals at a 15-point disadvantage in IQ relative to other individuals were only 79% as likely to live to age 76.

• Among the women, the less intelligent ones had a 40% increase in cancer deaths compared to the more intelligent ones, and the comparable figure for men was 27%.

• More intelligent individuals have greater health literacy than less intelligent ones.

Intelligence Testing

• Alfred Binet and Theodore Simon (1905):• The first proper intelligence test.• Measured comprehension, memory, and various

other psychological processes. • Other tests that followed are the Stanford-Binet test,

the Wechsler Intelligence Scale for Children, and the British Ability Scales.

Calculating IQ

• Tests are often used to calculate the person’s IQ, which means that the individual’s score is compared to scores obtained by other people taken from a standardized sample.

• Most IQ tests are designed to produce scores that are normally distributed—a bell-shaped curve, with the mean IQ being 100 and the standard deviation being about 16.

• This allows psychologists to determine the percentage of the population above or below an individual’s IQ score.

Standardized Tests

• Given to a large representative sample.• Age groups.• Compare an individual’s score against the

scores of other people.• Intelligence quotient (see next slide).

• Various abilities:• Numerical• Spatial• Reasoning• Perceptual speed

Reliability

• The extent to which a test provides consistent findings.

• Reliability is generally assessed by the test–retest method:• People take the same test on two separate occasions.• The scores of all the participants on the two

occasions are then correlated with each other.• The higher the correlation, the greater the reliability of

the test.

Validity

• The extent to which a test measures what it is supposed to be measuring:• Concurrent validity• Predictive validity

• IQ scores typically correlate:• +.5 with academic achievement and occupational status.• Job performance with complex jobs.

What term is used to describe an individual's test score correlating highly with their academic achievements?

a) Predictive validityb) Face validityc) Concurrent validityd) Construct validitye) Reliability

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Theories of Intelligence

• Factor analysis:• Giving people a range of tests to see whether the

results of each test correlate. • Technique enables psychologists to decide whether

the test is measuring one factor or several. • Can take several forms and this might explain why

psychologists have come up with different factor theories of intelligence.

Factor Theories• Spearman (1923):

• The first factor theory of intelligence.• General factor of intelligence, called g.• Specific factors associated with each test, which he called “s.”

• Thurstone (1938):• Seven factors (primary mental abilities):

– Inductive reasoning, verbal meaning, numerical ability, spatial ability, perceptual speed, memory, and verbal fluency.

• Carroll (1993): Hierarchical approach combined the above into three levels:

• Top: general factor.• Middle: general factors including fluid ability (nonverbal reasoning),

crystallized ability (knowledge).• Bottom: specific factors.

Which one of the following is NOT one of Thurstone’s primary mental abilities?

a) Verbal meaningb) Numerical abilityc) Spatial abilityd) Bodily-kinesthetic abilitye) Perceptual speed

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Hierarchical Approach

Carroll’s (1986) three-level hierarchical model of intelligence.

Gardner (1983): Multiple Intelligences

• Seven intelligences:• Logical-mathematical intelligence• Spatial intelligence• Musical intelligence• Bodily kinesthetic intelligence• Linguistic intelligence• Intrapersonal intelligence• Interpersonal intelligence(Naturalist intelligence, spiritual intelligence, existential

intelligence)?

Gardner (1983): Multiple Intelligences

• Suggested that there might be several other intelligences. • There were six criteria that he thought were needed to identify

intelligences, including the idea that the intelligence should depend on identifiable brain structures.

• In an attempt to gain evidence to support his theory Gardner (1993) undertook a study of geniuses (Freud, Einstein, Picasso, etc.).

• He found that there were some similarities in the background of his choice of creative individuals such as being ambitious, having childlike qualities, and having come from families that imposed high moral values.

Evaluation• Gardner’s approach to intelligence is broader in scope than most

others.• There is some supporting evidence (e.g., from geniuses; from brain-

damaged patients) for all seven intelligences originally proposed by Gardner.

• The seven intelligences correlate positively with each other, whereas Gardner (1983) assumed they were independent. That means that Gardner was wrong to disregard the general factor of intelligence.

• Musical and bodily kinesthetic intelligences are less important than the other intelligences in Western cultures, with many very successful people being tone-deaf and poorly coordinated.

• The criteria for an intelligence are too lenient.• The theory is descriptive rather than explanatory—it fails to explain

how each intelligence works.

Heredity and Environment

• Heredity consists of a person’s genetic endowment.

• Environment consists of the situations and experiences encountered by people in the course of their lives.

• Our makeup influences the types of environmental experiences we have.

Heredity and Environment

• Plomin (1990) identified three types of interdependence between genetic endowment and environment:• Active covariation• Passive covariation • Reactive covariation

• Genotype is an individual’s genetic potential.• Phenotype is observable characteristics.

Why is it difficult to give weightings to both the genetic and environmental components of intelligence?

a) It is exceptionally difficult to control all environmental factors

b) It would be unethical to institute a breeding program on humans

c) Genetic and environmental factors interactd) It is difficult to measure intelligencee) All of these

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Twin Studies

• Monozygotic twins• Identical twins• Identical genotypes

• Dizygotic twins• Fraternal twins• 50% shared genes

• The degree of similarity in intelligence shown by pairs of twins is usually reported in the form of correlations.

Twin Studies

• Bouchard and McGue (1981)• Reviewed 111 studies• Identical twins +.86• Fraternal twins +.6.

• McCartney et al. (1990)• Identical twins +.81• Fraternal twins +.59.

• Identical twins are treated in a more similar fashion than fraternal twins:

• Prenatal, parental treatment, playing together, dressing in a similar style, and being taught by the same teachers.

Twin Studies: Reared Apart

• Bouchard et al. (1990):• Identical twins +.75• This figure is higher than would be expected on an

environmentalist position.• Environmental factors are also important.

• Identical twins reared apart:• Brought up in different branches of the same family.• Separated at age 5.

Heritability • The technical definition of heritability is the ratio of

genetically caused variation to total variation (genetic + environmental variation) within any given population.

• Heritability is a population measure, and varies considerably from one population to another.

• Brace (1996) found that the heritability of intelligence was much higher among people living in affluent white American suburbs than among people living in American urban ghettos.

• In essence, the heritability measure combines two kinds of genetic influence:• Direct genetic influence • Indirect genetic influence

Heritability

• Mackintosh (1998) reviewed the evidence based on heritability measures:• He concluded that between 30% and 75% of

individual differences in intelligence in modern industrialized societies are due to genetic factors.

• Plomin (1988): the genetic influence on individual differences in IQ “increases from infancy (20%) to childhood (40% to adulthood (60%).”

Adoption Studies

• Another way of assessing the relative importance of heredity and environment in determining differences in intelligence.

• If heredity is more important than environment, adopted children’s IQs will be more similar to those of their biological parents than their adoptive parents.

• IQs of adopted children typically resemble those of their biological parents more than those of their adoptive parents.

Adoption Studies

• Selective placement:• Adoption agencies often have a policy of trying to

place infants in homes with similar educational and social backgrounds to those of their biological parents.

• Capron and Duyne (1989)• Study on adopted children, with no evidence of

selected placement.• Genetic and environmental factors of about equal

importance in determining the intelligence of the adopted children.

Environmental Studies

• Shared environment:• The common influences within a family.• Such as parental attitudes to education and parental income.

• Nonshared environment:• All those influences that are unique to any given child.

• Twin and adoption studies suggest that about 20% of individual differences in intelligence are due to nonshared environment.

Flynn Effect

• Flynn (1987, 1994)• Evidence from 20 Western countries.• A rapid rise in average IQ in most Western countries in

recent decades.• An increase of 2.9 points per decade in nonverbal IQ.• An increase of 3.7 points per decade in verbal IQ.• Factors:

• Increases in the number of years of education.

• Greater access to information.

• The increased cognitive complexity of the average person’s job.

• A large increase in the number of middle-class families.

Sameroff et al. (1993)• Ten risk factors that accounted for individual differences in IQ:

• Mother has a history of mental illness.• Mother did not go to high school.• Mother has severe anxiety.• Mother has rigid attitudes and values about her child’s development.• Few positive interactions between mother and child during infancy.• Head of household has a semi-skilled job.• Four or more children in the family.• Father does not live with the family.• Child belongs to a minority group.• Family suffered twenty or more stressful events in last 4 years.

• See next slide.

Which of the following was NOT one of the risk factors identified by Sameroff et al (1993) in the Rochester longitudinal study?

a) Mother has a history of mental illnessb) Father does not live with the familyc) Mother has a full-time jobd) Family suffered 20 or more stressful events during the child's first yeare) Mother has rigid attitudes about her child's development

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Size Does Matter!

• When psychologists first studied the link between brain size and intelligence, they found practically no relationship.

• These early studies were limited because findings were based on imprecise estimates of brain size (skull size, measuring the sizes of the shrunken brains of people who had recently died).

• Today we can obtain good measures of brain size in living people by using brain-imaging techniques such as magnetic resonance imaging (MRI).

Size Does Matter!

• McDaniel (2005) found the average correlation between brain size or volume and intelligence was +.33, indicating that people with larger brains do tend to be more intelligent.

• The average correlation between brain volume and intelligence between the sexes was +.40 for females and +.34 for males.

• There is also evidence from studies on children that nutritionally enhanced diets produce increases in IQ (Benton, 2001).

Size Does Matter!

• Males vs. females:• Females have smaller brains than males.• Possible inference that men are more intelligent than

women does NOT follow—in fact, the two sexes have essentially the same mean IQ (Mackintosh, 1998).

• Females tend to have greater verbal abilities than males.

• Males have greater spatial abilities.

Size Does Matter!

• There is recent evidence that there may be important sex differences in brain structures underlying intelligence.

• Haier et al. (2005) considered two kinds of nerve tissue in the brain: gray matter and white matter. • Women had more white matter and fewer gray matter

brain areas related to intelligence than did men.

Research has found that females tend to have ______ abilities than males, and males have ______ abilities. [Fill in the blanks.]

a) Greater verbal; greater spatialb) Greater spatial; greater verbalc) Lower verbal; lower speciald) Inadequate spatial; no spatiale) e) Greater verbal; no verbal

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The End