Intelligence

Brian J. Piper, Ph.D.

Assessing Intelligence The Origins of Intelligence Testing

Modern Tests of Mental Abilities

Principles of Test Construction

The Dynamics of Intelligence Extremes of Intelligence

Assessing Intelligence

Psychologists define intelligence testing as a method for assessing an individual’s mental aptitudes and comparing them with others

using numerical scores.

Alfred Binet

Alfred Binet and his colleague Théodore Simon practiced a

more modern form of intelligence testing by developing questions

that would predict children’s future

progress in the Paris school system.

1857-1911

Definition of Intelligence

• "It seems to us that in intelligence there is a fundamental faculty, the alteration or the lack of which, is of the utmost importance for practical life. This faculty is judgment, otherwise called good sense, practical sense, initiative, the faculty of adapting one's self to circumstances. A person may be a moron or an imbecile if he is lacking in judgment; but with good judgment he can never be either. Indeed the rest of the intellectual faculties seem of little importance in comparison with judgment" (Binet & Simon, 1916, 1973, pp.42-43)

Alfred Binet

Normal versus Abnormal

Environmentalist

1857-1911

Lewis TermanIn the US, Lewis Terman adapted Binet’s test for

American school children and named

the test the Stanford-Binet Test. The following is the

formula of Intelligence Quotient (IQ), introduced by

William Stern: 1857-1936

Lewis Terman

1857-1936

• Eugenics

• Quantitative

Eugenics (9.5 min, 1st 2 best):http://www.youtube.com/watch?v=ufqOe0_pres

David Wechsler

Wechsler developed the:

Wechsler Adult Intelligence Scale (WAIS): 1939, 16+ Wechsler Intelligence Scale for Children (WISC)1949, 6-16

Wechsler Preschool & Primary School Scale of Intelligence, 1967, Ages: 2.5 - 7

1896 – 1981

Intelligence

• the global capacity to act purposefully, to think rationally, and to deal effectively with [one's] environment

WAISWAIS measures overall intelligence and 11 other aspects related to intelligence that

are designed to assess clinical and educational problems.

WASI Exercise

Principles of Test Construction

For a psychological test to be acceptable it must fulfill the following three criteria:

1. Standardization

2. Reliability3. Validity

Standardization

Standardizing a test involves administering the test to a representative sample of future test takers in order to establish a basis for

meaningful comparison.

Representative: Age, Ethnicity, Sex

Normal Curve

Standardized tests establish a normal distribution of scores on a tested

population in a bell-shaped pattern called the normal curve.

Flynn Effect

In the past 60 years, intelligence scores have risen steadily by an average of 27

points. This phenomenon is known as the Flynn effect.

Reliability

A test is reliable when it yields consistent results. To establish reliability researchers

establish different procedures:

1. Split-half Reliability: Dividing the test into two equal halves and assessing how consistent the scores are.

2. Test-Retest Reliability: Using the same test on two occasions to measure consistency.

Validity

Validity of a test refers to what the test is supposed to measure or predict.

1. Content Validity: Refers to the extent a test measures a particular behavior or trait.

2. Predictive Validity: Refers to the function of a test in predicting a particular behavior or trait.

GRE & GPA

Extremes of Intelligence

A valid intelligence test divides two groups of people into two extremes: the mentally retarded (IQ 70) and individuals with high

intelligence (IQ 135). These two groups are significantly different.

High Intelligence

Contrary to popular belief, people with high intelligence test scores tend to be healthy,

well adjusted, and unusually successful academically.

Mental Retardation

Mentally retarded individuals required constant supervision a few decades ago, but with a supportive family environment and special education they can now care for

themselves.

Mental Retardation: High dose Fetal Alcohol

Autism

• Neurodevelopmental disorder

• Prevalence: 0.2%• Symptoms

– Social– Communication– Self-stimulation

Savant

• Steven Wiltshire• http://www.youtube.com/watch?v=ckqDX2XpdyY

1974 -

Summary

• Intelligence tests have a long history (Binet versus Terman)

• Test Characteristics– Reliability– Validity