Intelligence

Intelligence• Wechsler defined it as the global capacity to think rationally, act purposefully, and

deal effectively with the environment• The ability to learn from experience, solve problems, and use knowledge to adapt to

a new situation• Intelligence is reflected in effective, rational, and goal-directed behavior.• Is intelligence one thing or are there multiple intelligences?• Play “Pros and Cons of Intelligence Tests” (6:29) Segment #17 from Psychology:

The Human Experience.– This is a good review of what you’ve read and highlights how IQ tests have been used in a

variety of ways by the government and other agencies.

Measuring Intelligence

Intelligence tests try to measure general mental abilities not “book smarts” or

knowledge in a specific area

Intelligence Testing:Alfred Binet

Binet’s “Mental Age”• Hired by the French government to develop a test to determine

students who had special needs. • His test focused on mental abilities like memory, attention, and

the ability to understand similarities and differences NOT math and reading.

• Arranged questions in order of difficulty with simplest first.• Compared student’s performance with those of other kids their

age.• Developed the term, “mental age” which meant the age of the

child’s mental abilities. A seven year old operating at a 9 year old’s level would have a mental age of 9.

• Binet never meant for his test to be used to measure intelligence. He only wanted to identify kids with special needs.

• He felt intelligence was too complex to capture in a test.

• Intelligence—collection of higher-order mental abilities loosely related to one another

• Assumed children’s intellectual abilities grew every year

• Intelligence is nurtured• Developer of the first test to classify

children’s abilities using the concept of mental age. Used to predict academic performance

• Did not rank “normal” students according to the scores

1859-1911

Alfred Binet

Intelligence Testing:Lewis Terman

(1877-1956)

Lewis Terman

Found that intelligence alone is not enough to be a success. Only those that had personality factors that were more goal-oriented,

greater perseverance and self-confidence. Essentially, those with a willingness to work hard were successful.

Intelligence is no guarantee of success in professional life.

•Terman believed that IQ was a fixed, inborn characteristic and would equate in to school success (this against what Binet believed).•Terman did a longitudinal study of children whose average IQ scores were 150 (140 is genius level).

Lewis Terman & William SternStanford-Binet IQ Test

Stanford-Binet Intelligence Test IQ=(MA/CA)*100 IQ=Intelligence Quotient MA=Mental Age CA=Chronological Age• A score of 100 would be considered average• Formula has been replaced with modern versions

•Intelligence Quotient - The number that results from Terman and Stern’s formula for computing the level of a person’s intelligence

Calculating Intelligence

For an average 7 yr old…MA=7CA=7IQ=(MA/CA)*100IQ=(7/7)*100IQ=1*100IQ=100 (average)

Calculating Intelligence

For an average 11 yr old…MA=11CA=11IQ=(MA/CA)*100IQ=(11/11)*100IQ=1*100IQ=100

Calculating Intelligence

For an above average 10 yr old…MA=12CA=10IQ=(MA/CA)*100IQ=(12/10)*100IQ=1.2*100IQ=120

Calculating Intelligence

For a below average 8 yr old…MA=6CA=8IQ=(MA/CA)*100IQ=(6/8)*100IQ=.75*100IQ=75

Calculating Intelligence

A glitch…MA levels off at about 18

Average 18 yr oldMA=18CA=18IQ=(18/18)*100IQ=(1/1)*100=100

Average 36 yr oldMA=18CA=36IQ=(18/36)*100IQ=(1/2)*100=50

Problems with Intelligence Testing

• Army Alpha written test and the Army Beta oral test used in WWI to test the IQ of recruits and draftees.

• These later used by immigration and resulted in certain nationalities being labeled as “unfit” resulting in quotas.

How Much Stock can we put into IQ Scores?

• Not too much.

• To regard an abstract concept as if it were a real, concrete thing is called reification.

Modern Intelligence Tests:

Weschsler Test

Group Tests

David Wechsler (1896-1981)

• Developed the Wechsler intelligence scales which included:

– Different tests for different age groups

– Separate verbal and nonverbal scores

– Subtests and subtest scores

The Wechsler tests• Modeled after Binet’s but improved it in two ways.1. Designed test for both adults and children.

– WISC-IV = Wechsler Intelligence Scale for children– WAIS-IV = Wechsler Adult Intelligence Scale

2. Provided scores in 11 different subtests for 11 abilities which were grouped to show a performance and verbal score. • It showed an individual’s strengths and weaknesses in a

variety of areas.

The Subtests of the Wechsler Test and how they’re used

• Verbal score – obtained from subtests in vocab, comprehension, knowledge and general info.

• Performance score – obtained by nonverbal subtests like identifying the missing part in a picture, arranging pictures into a story, arranging blocks to match a pattern.

• Discrepancies in certain scores (high score in one area with a low score in another area can indicate a learning disability). It can also mean there was a cultural disadvantage for the person taking the test.

• IQ Global score determined by comparing to the average score of others in your same general age group rather than by mental age. Average score is fixed for each age group at 100. Average or 2/3 of all scores fall between 85-115.

Subtests of Wechsler

Testing Spatial Reasoning

Test Construction:Reliability and

Validity

Types of Tests

• Achievement test—designed to measure level of knowledge, skill, or accomplishment in a particular area – classroom tests at the end of a unit

• Aptitude test—designed to measure capability to benefit from education or training– ACT and SAT

• Interest test—measures self-reported vocational interests and skills– PLAN Test

Qualities of Good Tests

• Standardized—administered to large groups of people under uniform conditions to establish norms

• Reliable—ability to produce consistent results when administered on repeated occasions under similar conditions

• Valid—ability to measure what the test is intended to measure

Standardized Scoring of Wechsler Tests

• All raw scores converted to standardized scores

• Normal distribution

• Mean of 100• Standard

deviation of 15

Types of Reliability

• Test-retest reliability - taking the same test and receiving a similar score

• Split-half - the score on one half of a test’s questions is similar to the score on the other half

• Scorer reliability – the score of the test should be similar no matter which scorer is scoring the test

What do IQ tests measure about your mind?

• Mental speed and span of working memory– typically use a digit span test to measure this– more recent studies find significant correlations

between reaction times and IQ scores

• Why is this important?– mental quickness may expand capacity of

working memory

Test Validity

• The extent to which a test measures or predicts what it is suppose to

• Does an achievement test accurately measure accomplishments?

• Does an aptitude test accurately measure the person’s future performance?

• One needs to know the purpose of the test