Module 13

Intelligence

DEFINING INTELLIGENCE• Two-factor theory

– Psychometric approach• measures or quantifies cognitive abilities or factors that

are thought to be involved in intellectual performance– Two-factor theory

• by Charles Spearman • says that intelligence has two factors:• general mental ability factor “g”• represents what different cognitive tasks have in

common• specific factors which include specific mental abilities

such as mathematical, mechanical, or verbal skills “s”

DEFINING INTELLIGENCE (CONT.)• Multiple-intelligence theory

– Gardner’s multiple-intelligence theory• Howard Gardner• instead of one kind of general intelligence, there

are at least seven different kinds which include:• verbal intelligence• musical intelligence• logical mathematical intelligence• spatial intelligence• body movement intelligence (to understand

oneself)• intelligence to understand others

DEFINING INTELLIGENCE (CONT.)

• Triarchic theory– Robert Sternberg

• says that intelligence can be divided into three different kinds of reasoning processes

1.uses analytical or logical thinking skills that are measured by traditional intelligence tests

2.uses problem-solving skills that require creative thinking and the ability to learn from experience

3.uses practical thinking skills that help a person adjust to, and cope with, his or her sociocultural environment

MEASURING INTELLIGENCE

• Earlier attempts to measure intelligence– head size and intelligence

• Francis Galton– noticed that intelligent people often had intelligent

relatives and concluded that intelligence was, to a large extent, biological or inherited

– low correlation between head size and intelligence– using head size as a measure of intelligence was

abandoned in favor of using skull or brain size

MEASURING INTELLIGENCE (CONT.)

MEASURING INTELLIGENCE (CONT.)

• Earlier attempts to measure intelligence– Brain size and intelligence

• Paul Broca• claimed there was a relationship between size of

brain and intelligence• larger brains indicating more intelligence• later reanalysis of Broca’s data indicted that

measures of brain size proved to be unreliable and poorly correlated with intelligence

MEASURING INTELLIGENCE (CONT.)

• Earlier attempts to measure intelligence– brain size and achievement– enormous variation in brain size and achievement– brain size, sex differences, and intelligence– women’s brains weigh about 10% less than men’s– little or no difference in intelligence between men and

women– larger size of men’s brains does not result in higher

IQs

MEASURING INTELLIGENCE (CONT.)

• Binet’s breakthrough– Alfred Binet

• believed that intelligence was a collection of mental abilities and that the best way to assess intelligence was to measure a person’s ability to perform cognitive tasks, such as understanding the meanings of words or being able to follow directions

• Binet-Simon Intelligence Scale• contained items arranged in order of increasing

difficulty• measured vocabulary, memory, common knowledge,

and other cognitive abilities

MEASURING INTELLIGENCE (CONT.)

• Binet’s breakthrough– mental age: measure of intelligence– Binet and Simon revised their intelligence scale to

solve several problems in their original scale– mental age– method of estimating a child’s intellectual progress by

comparing the child’s score on an intelligence test to the scores of average children of the same age

MEASURING INTELLIGENCE (CONT.)

• Formula for IQ– intelligence quotient

• computed by dividing a child’s mental age (MA), as measured in an intelligence test, by the child’s chronological age (CA) and multiplying the result by 100

MEASURING INTELLIGENCE (CONT.)

MEASURING INTELLIGENCE (CONT.)

• Wechsler Intelligence Scale– most widely used IQ tests– Wechsler Adult Intelligence Scale (WAIS-III), ages 16

and older– Wechsler Intelligence Scale for Children (WISC-III) for

children ages 3-16– both have items that are organized into various

subtests– verbal section– performance section– verbal and performance combined give a single IQ

MEASURING INTELLIGENCE (CONT.)

• Two characteristics of tests– Validity

• means that the test measures what it is supposed to measure

– Reliability• refers to consistency: score on a test at one point

in time should be similar to the score obtained by the same person on a similar test at a later point in time

DISTRIBUTION & USE OF IQ SCORES

• Normal distribution of IQ scores– Normal distribution

• refers to a statistical arrangement of scores so that they resemble the shape of a bell and, thus, is said to be a bell-shaped curve

DISTRIBUTION & USE OF IQ SCORES (CONT.)

DISTRIBUTION & USE OF IQ SCORES (CONT.)

• Mental retardation: IQ scores– Mental retardation

• refers to a substantial limitation in present functioning that is characterized by significantly subaverage intellectual functioning, along with related limitations in two of ten areas, including communication, self-care, home living, social skills, and safety

• borderline mentally retarded: IQs from 50 to 75• mildly/moderately mentally retarded: IQs from 35 to 50• severely/profound mentally retarded: IQs from 20 to 40

DISTRIBUTION & USE OF IQ SCORES (CONT.)

• Mental retardation: IQ scores– Causes

• Organic retardation– results from genetic problems or brain damage

• Cultural-familial retardation– results from a greatly impoverished

environment.

DISTRIBUTION & USE OF IQ SCORES (CONT.)

• Vast majority: IQ scores – about 95%, have scores that fall between 70 and 130

• Gifted: IQ scores• Moderately gifted

– usually defined by an IQ score between 130 and 150

• Profoundly gifted – usually defined by an IQ score around 180 or

above

POTENTIAL PROBLEMS OF IQ TESTING

• Binet’s Warnings

– intelligence tests do not measure innate abilities or natural intelligence

– intelligence tests, by themselves, should not be used to label people

POTENTIAL PROBLEMS OF IQ TESTING

• Cultural Bias– The wording of the questions and the experiences on

which the questions are used• Nonintellectual Factors

– refer to noncognitive factors, such as attitude, experience, and emotional functioning, that may help or hinder performance on tests

NATURE-NURTURE QUESTION

• Definitions – asks how nature-hereditary or genetic factors-

interacts with nurture-environmental factors-in the development of a person’s intellectual, emotional, personal, and social abilities

• Twin studies– Fraternal twins

• like siblings (brothers and sisters), develop from separate eggs and 50% of their genes in common

NATURE-NURTURE QUESTION (CONT.)

• Twin studies– Identical twins

• develop from a single egg and thus have identical genes, which means that they have 100% of their genes in common

– Interaction of nature and nurture• when researchers report that genetic factors

influence intelligence (IQ scores)• mean that genetic factors influence cognitive

abilities to varying degrees, depending on the environment

NATURE-NURTURE QUESTION (CONT.)

• Adoption studies– children with limited social-educational opportunities

and low IQs were adopted by parents who could provide increased social-educational opportunities

– studies show that children with poor educational opportunities and low IQ scores can show an increase in IQ scores when they are adopted into families that provide increased educational opportunities

NATURE-NURTURE QUESTION (CONT.)

• Interaction: nature and nurture– Heritability

• number that indicates the amount or proportion of some ability, characteristic, or trait that can be attributed to genetic factors (nature)

– Reaction range• indicates the extent to which traits, abilities, or IQ

scores may increase or decrease as a result of interaction with environmental factors