Testing and Individual Differences

Chapter, 11

How do we measure individual differences?

Core Concept:• Measuring individual differences is an

essential component of psychology, but strict guidelines and ethical standards must be followed to ensure results and conclusions are valid and appropriate

Validity

• Validity is the term use when asking whether a test measures what it purports to measure.– For example: if you were to take a psychology test on which all the

questions were related to chemistry, it would have a very low validity score.

• Types:• Face validity: whether a test looks like it tests what its supposed to.• Content validity: representative of a larger body of knowledge (AP

EXAM)• Item analysis: each question examined to see if it relates back to the

objective.• Criterion validity: measures performance of the test taker against a

specific learning goal.

Reliability

• Reliability reflects whether a test yields the same results over time.– Example: If you were to take a test twice and get 70%

right the first time and 30% right the second time, that test would be revealed to have very low reliability.

• Types:• Test-retest reliability: compare the scores of the same

test, same taker.• Split-half reliability: Test is split into two, the halves of

the test are compared.

Standardization and Norms

• How can tests be used to compare individuals?– 1) the administration of and scoring guidelines are

the same for each student.– 2) the results of the test of the test can be used to

draw conclusions about the test takers in regard to the objective of the tests.

• Norms: How can results be compared?– Statistics! Statistics are used to establish what is

called a normal curve or bell curve.• Normal range –

Scores falling near the middle of a normal distribution

The Normal Distribution of IQ Scores

Types of Test

• There are two types of test: objective and subjective.

• Objective tests: generally multiple choice and can be scored easily by a machine and the results presented and interpreted quickly.– Meyers Briggs, MMPI

Types of Test

• Subjective:– Individuals are given an ambiguous figure and

asked to describe what they see or are given open ended situations and asked to finish a story.• TAT Test, Rorschach Inkblot test

– An issue: Inter-Rater Reliability: a measure of how similarly two different test scorers would score on the test.

Ethics

• Ethical concerns related to testing involve:– The confidentiality of the test results– How to report the results– How to use the test to compare individuals– The impact of tests on society as a whole

How is IntelligenceMeasured?

Core Concept:• Intelligence testing has a history of

controversy, but most psychologists now view intelligence as a normally distributed trait that can be measured by performance on a variety of tasks

Binet and Simon

• In 1904, France passed a law that required all French children to attend school and the government needed a means of identifying those who needed remedial help.

• Binet and Simon were asked to design a test for this purpose. They responded with 30 problems sampling a variety of abilities.

• This test successfully predicted which children could, or could not, handle normal school work.

Binet and Simon

• Binet-Simon Test calculated a child’s mental age and compared it to his or her chronological age.

• 4 Important features:– 1. Estimate of current performance, not a measure of

innate intelligence.– 2. Test scores were used to identify children who

needed special help, not to label them.– 3.They emphasized that training and opportunity could

affect intelligence.– 4. They constructed their test empirically.

American Psychologist Borrow the Test

• American psychologist borrow Binet-Simon test and change it in these ways:– 1. Changed it to the IQ Test.– 2. Modified the scoring procedure, expanded the

test’s content, and obtained scores from a large normative group of people, including adults.

• Thoughts?

Why?

• Why did IQ tests become quickly so popular in the US. 3 Reasons:

• 1.Immigration ( causing global economic, social, and political crisis’)

• 2. New laws requiring Universal Education.• 3. WW1—and the military needed a way of

accessing and classifying recruits.

New Form

• The Stanford-Binet Intelligence Scale is the most respected of the new American tests of intelligence.

• Lewis Terman adapted the original test for U.S. children by standardizing its administration and age level norms.

• Better suited for spotting learning problems.• He introduced the concept of the Intelligence

Quotient (IQ)

Stanford-Binet

• Intelligence quotient –A numerical score on an intelligence test, original computed by dividing a person’s mental age by chronological age and multiplying by 100.

• IQ= Mental Age x100_____________________Chronological Age

Today

• Wide choice of intelligence tests.• Most prominent: Wechsler Adult Intelligence

Scale (WAIS) (WAIC) children (WPPSI) Pre school.

• Measures: vocabulary, verbal comprehension, arithmetic ability, similarities.

• Individual tests, given to one person at a time.

Problems with IQ Formula

• Problems quickly arose when psychologist used this formula on adults.

• So an example now:IQ = Mental Age =15x 100 = 50 __________ ___

Chronological 30

Exceptional Children

• Mental retardation –Often conceived as representing the lower 2% of the IQ range

• Giftedness –Often conceived as representingthe upper 2% of the IQ range

Mental Retardation

• Involves “significantly sub average intellectual functioning” that becomes apparent before 18.

• Also involves limitations in at least two of the following areas: “communication, self-care, home living, social skills, community use, self direction, health and safety, academics, leisure, and work.”

Causes

• Many causes:– Genetic– Environmental (Fetal Alcohol Syndrome)– Postnatal accidents that damage the cognitive

regions of the brain.– Or deprivation and neglect.

Cures

• Although currently there are no cures, there are some preventative measures.

• PKU- a test preformed on newborn babies. Can detect early cases and by special diet some types can be prevented.

• But, mainly the ways to handle mental retardation center around: special ed programs, counseling, and life centered programs.

Giftedness

• Top 1 or 2 % of IQ tests.• They excel in most areas.• Terman’s Longitudinal Study.

Dealing:– Enroll child in special after school classes.– Hire a tutor– Send the child to a private school– Do nothing special

What Are the Componentsof Intelligence?

Core Concept:• Some psychologists believe that the essence

of intelligence is a single, general factor, while others believe intelligence is best described as a collection of distinct abilities

What Are the Componentsof Intelligence?

• Savant syndrome –Found in individuals who have a remarkable talent even though they are mentally slow in other domains

• Twins

Psychometric Theories

• Psychometric: field of “mental measurements”. Provided us with most of our IQ tests, achievement tests, and personality tests.

G Factor

• Developed by Charles Spearman in the 1920’s• g Factor –

A general ability, (innate) as the main factor underlying all intelligent mental activity

• Recent neuroscience has found some support for this theory. All various tests of g, use a portion of the brain’s frontal lobe.

Cattell Is back

• Using mathematical techniques, Cattell determined that general intelligence can be broken down into 2 components.

• Crystallized intelligence –The knowledge a person has acquired, plus the ability to access that knowledge

• Fluid intelligence –The ability to see complex relationships and solve problems

Cognitive Theories

• 20th century cognitive view said that intelligence involves cognitive processes that contribute to success in many areas of life—not just school.

• Sternberg’s Triarchic Theory • Gardner’s Multiple Intelligences

Sternberg’s Triarchic Theory

Gardner’s Multiple Intelligence

Gardner’s Three New Intelligences

• Naturalistic intelligence: classifying living things as members of diverse groups.

• Spiritual intelligence: abstract spiritual terms.• Existential intelligence: largest and smallest

components of the universe (death).Cultural western societies promote the first 2 types, while other societies value one or more other kinds.

Psychology in Your Life

How Do Psychologists Explain IQ Differences Among Groups?

• Intelligence can have different meanings in different cultures. – Pacifically, navigating a boat more important or

your SAT score?• Core concept: While most psychologists agree

that both heredity and environment affect intelligence, they disagree on the source of IQ differences among racial and social groups

Intelligence/ Immigration

• Congress passed the 1924 Immigration Restriction Act that restricted immigration for people who were proved to be “inferior intellect”.

Intelligence influenced by Heredity

• Hereditarian arguments maintain that intelligence is substantially influenced by genetics.

• Studies:

Intelligence influenced by Environment

• Environmental approaches argue that intelligence can be dramatically shaped by influences such as• Health• Economics• Education

Heritability and Group Differences

• Heritability – Amount of trait variation within a group, raised under the same conditions, that can be attributed to genetic differences

• Heritability says nothing about between-group differences

Heritability and Group Differences

• Research with twins and adopted children shows genetic influences on a wide range of attributes, including intelligence

• Research has also shown that racial and class differences in IQ scores can be eliminated by environmental changes

The Jensen Controversy

The Scarr and Weinberg Adoption Study

Social Class and IQ

Head Start

Test Biases

The Bell Curve