The first intelligence test was developed by psychologist Alfred Binet, in 1905, in Paris, France. He was hired by the public school system to develop a test which would identify students who were in need of special education classes. He came up with measures of many mental abilities, and gave these tests to the children in the school system. He assigned scores to the test results, based on the ages of the children who took the test. He called the scores “mental ages”, based on the typical score earned by children of a specific age. A Mental Age of 8 was the average score achieved by the eight years olds. So a child who scored a Mental Age of 8 on the test scored the same as the average 8 year old. If a seven year old scores a Mental Age of 8, is he smart or stupid?

Alfred Binet

In 1916, psychologist Lewis Terman, of Stanford University, brought Binet’s test to the United States, standardized it on American children, and named the American version the Stanford-Binet Intelligence Scale. Terman introduced the concept of the Intelligence Quotient (I.Q.), which he calculated by dividing a child’s Chronological Age (actual age in years, months, and days) by his Mental Age score on the test, and multiplying the result by 100. So the formula was I.Q. = MA/CA x 100. So a 10 year old child with a Mental Age score of 12 years would have an I.Q. of what?

The child’s I.Q. is 120 Lewis Terman

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Two versions

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WAIS-III and WISC-III

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Each has two subscales

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Verbal skills subscale Performance skills subscale

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Produces verbal, performance, and overall scores

Verbal Items – Items that require the use of language.

Performance Items – Non-language items The Wechsler Scales are the major individual intelligence tests used in the USA today.

Administered by one examiner to many people at a time Advantages: Less bias Objective scoring Disadvantages: Examiner may miss problems Some are not used to taking group tests Learning disabilities do better on individual tests

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Heredity

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IQs of identical twins

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adoption studies

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Environment

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nutrition

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human interaction socioeconomic status (SES) of parents

What is your I.Q.?

What is the I.Q. of the average graduating college senior In the United States? What can a person with an I.Q. of 65 do?

What is a “genius?”

Classification

Very Superior Superior High Average Average Low Average Borderline Mental Retardation

IQ Score

130 and above 120-129 110-119 90-109 80-89 70-79 69 and below

Mental Retardation

Mild Mental Retardation Moderate Mental Retardation Severe Mental Retardation Profound Mental Retardation

Percent Included

2.2

6.7

16.1

50.00

16.1

6.7

2.2

IQ 50-55 to 70 I.Q. 35-40 to 50-55 I.Q. 20-25 to 35-40 I.Q. below 20 or 25

Psychologists today no longer use Terman’s formula to calculate IQ test scores. Instead, modern intelligence tests apply statistical methods to produce a score reflecting one's performance as compared to the average performance of his peers . The normal IQ score is still 100, meaning that the average score people get is 100. That happens because IQ test scores have a so-called “normal” distribution. In a normal distribution, most of the values cluster around the average with few values that differ significantly from it. That creates a bell shaped curve, known as the IQ bell curve, which is illustrated below.

 Genetic Conditions - Down Syndrome, Fragile X, PKU, Overexposure to X-Rays  Problems During Pregnancy - Use of alcohol or drugs by the pregnant mother can cause mental retardation. Malnutrition, rubella, glandular disorders and diabetes, cytomegalovirus, and many other illnesses of the mother during pregnancy may result in a child being born with mental retardation. Physical malformations of the brain and HIV infection originating in prenatal life may also result in mental retardation.  Problems at Birth - Although any birth condition of unusual stress may injure the infant’s brain, prematurity and low birth weight predict serious problems more often than any other conditions.  Problems after birth - Childhood diseases such as whooping cough, chicken pox, measles, and diseases which may lead to meningitis and encephalitis can damage the brain, as can accidents such as a blow to the head or near drowning. Substances such as lead and mercury can cause irreparable damage to the brain and nervous system.  Poverty and cultural deprivation - Children in poor families may become mentally retarded because of malnutrition, disease-producing conditions, inadequate medical care and environmental health hazards. Also, children in disadvantaged areas may be deprived of many common cultural and day- to-day experiences provided to other youngsters. Research suggests that such under-stimulation can result in irreversible damage and can serve as a cause of mental retardation.

 Mild Mental Retardation - Approximately 85% of the mentally retarded population is in the mildly retarded category. Their IQ score ranges from 50-75, and they can often acquire academic skills up to the 6th grade level. They can become fairly self sufficient and in some cases live independently, with community and social support.

 Moderate Mental Retardation - About 10% of the mentally retarded population is considered moderately retarded. Moderately retarded individuals have IQ scores ranging from 35-55. They can carry out work and self-care tasks with moderate supervision. They typically acquire communication skills in childhood and are able to live and function successfully within the community in a supervised environment such as a group home.

 Severe Mental Retardation - About 3-4% of the mentally retarded population is severely retarded. Severely retarded individuals have IQ scores of 20-40. They may master very basic self-care skills and some communication skills. Many severely retarded individuals are able to live in a group home.

 Profound Mental Retardation - Only 1-2% of the mentally retarded population is classified as profoundly retarded. Profoundly retarded individuals have IQ scores under 20-25. They may be able to develop basic self-care and communication skills with appropriate support and training. Their retardation is often caused by an accompanying neurological disorder. The profoundly retarded need a high level of structure and supervision.

 The term “gifted” has no precise definition. Many schools or programs for the gifted require an I.Q. of 130 or above.

 Gifted children are far above average in at least one ability, but may be much closer to average in other abilities. That being said, people who are far above average in one ability are usually above average in other abilities.

 The term “genius” has no technical definition, but it implies an extreme degree of ability in at least one area. The brightest of children, to whom this term may be fairly applied, often teach themselves to read at a very early age. For example a three year old child may be reading at the second grade level, without any training, other than being read to while sitting in an adult’s lap. These children develop very large vocabularies and use their words correctly (and with correct grammar.) They may go to college at age 10 or 12, and be in graduate school a couple of years later.  Most gifted children are well adjusted socially.

Here is an eight year old college student.

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I.Q. Tests Do Measure:

    Analytical Intelligence Ability to learn how to do things, acquire new knowledge, solve problems, carry out tasks effectively. (Sternberg) Logical-Mathematical Intelligence (Gardner) Linguistic Intelligence (Gardner) Spatial Intelligence (Gardner)        

I.Q. Tests Do Not Measure:

Creativity (Sternberg) Musical Intelligence Gardner) Bodily-Kinesthetic Intelligence (Gardner) Interpersonal Intelligence (Gardner) Intrapersonal Intelligence (Gardner) Naturalistic Intelligence Gardner) Emotional Intelligence – Knowing one’s own emotions, managing one’s emotions, recognizing the emotions of other people, and managing relationships. (Goleman)

All good tests must be valid and reliable.

Validity

means that the test measures what it claims to measure.

If I make up a test and call it an I.Q. test but the test consists of measuring your shoe size, is my new test valid?

If I make up a test of knowledge of American History, and it has only one question on it, that being “Which explorer discovered the Pacific Ocean”, is this a valid test? Why or why not?

Reliability

means that the test produces consistent results. If I give you an I.Q. test on January 5, and then test you again on July 7, the results of the two tests should be very similar to each other. If the results are not consistent, the test is not reliable.

By the way, the explorer who is credited with discovering the Pacific Ocean is Vasco Núñez de Balboa.

Balboa was a Spanish conquistador and explorer. He was the first European to see (and stand in the waters of) the eastern shore of the Pacific Ocean, on September 13, 1513.

King Ferdinand of Spain appointed Balboa to serve under Dévila as governor of Panama. Unfortunately for Balboa, Dávila was a jealous man who did not like seeing the growing popularity and influence which Balboa was developing. In 1518, Governor Pedro Arias Dávila falsely accused Balboa of treason, had him arrested, ordered a speedy trial and sentenced Balboa to death. In January 1519, Balboa and four friends were beheaded.