Intelligence Testing

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Intelligence Testing
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A brief history of intelligence

• The concept of 'intelligence' is relatively new,
  unknown a century ago, though it comes from older
  Latin roots
• inter between, within legere to bring
  together, gather, pick out, choose, catch up,
  catch with the eye, read intellegere to see
  into, perceive, understand
• Francis Galton revived the term in the late 19th
  century, arguing for its innateness

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A brief history of intelligence

• Some objected to the innateness bias, and
  suggested the term be replaced with 'general
  scholastic ability' or 'general educational
  ability'
• However, this did not catch on most theorists
  today posit a construct of intelligence that is
  independent of education

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Defining intelligence

• Binet (1916) defined it as the capacity to judge
  well, to reason well, and to comprehend well
• Terman (1916) defined it as the capacity to form
  concepts and grasp their significance
• Pintner (1921) defined it as the ability of an
  individual to adapt well to new situations in
  life
• Thorndike (1921) defined it as the power of good
  responses from the point of view of truth or fact
• Thurstone (1921) defined it as the capacity to
  inhibit instinctive response, imagine a different
  response, and realize the response modification
  into behavior

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Defining intelligence

• Spearman (1923) defined it as a general ability
  involving mainly the ability to see relations and
  correlates
• Wechlser (1939) defined it as the global capacity
  of an individual to act purposefully, think
  rationally, and deal effectively with the
  environment
• Piaget (1972) defined it as referring to the
  superior forms of organization or equilibrium of
  cognitive structuring used for adaptation to the
  to the physical and social environment
• Sternberg (1985) defined it as the mental
  capacity to automatize information processing and
  to emit contextually appropriate behavior in
  response to novelty
• Gardner (1986) defined it as the ability to solve
  problems or fashion products valued within some
  setting.

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Defining intelligence

• You can take your pick of definitions but most
  agree that intelligence has to do with the
  related capacities of
• i.) Learning from experience
• ii.) Adapting to ones environment
• Think of a person lacking either of these, and
  you pick out people who seem to lack intelligence
• Note however that very few formal tests of
  intelligence really demand subjects to do either
  of these!

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Defining intelligence

• Factor analystic studies (Sternberg, 1981) of
  informal views of an 'ideally intelligent' person
  capture these characteristics
• They emphasize practical problem solving and
  social competence (the same thing?) as signs of
  intelligence, along with a factor loaded on
  verbal ability

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Early History on the Intellectually Impaired-Era
of Extermination

• prevailing attitude is one of extermination
• Individuals with disabilities were seldom allowed
  to live since physical prowess was valued and
  essential for the survival of the group

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Prehistoric Time

• abandonment
• murdered
• failure to survive (hard life style)

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Early Historic Time (1552 B.C.-300 A.D.)

• very few records
• first written reference found in Egyptian papyrus
  (Therapeutic Papyrus of Thebes)
• persons with the most severe disabilities allowed
  to survive if able
• many forced to beg for food and shelter
• occurrence of a disability viewed as sickness and
  as a punishment from God for wrongdoing by the
  parent

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Aristotle stated that man differs from animals by
intellect alone--there was no concept of
individual differences--and intellect was noted
by man's ability to speak.

• Therefore if an individual was unable to speak
  then s/he was no different than an animal.

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Era of Ridicule

• During this 1400 years most of the attitude of
  people concerning others with disabilities was
  that of ridicule or neglect.
• persons viewed with a mixture of fear and
  reverence.

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Middle Ages (300-1350 A.D.)

• emphasis was on "other" world--little concern for
  anything but religion and one's own soul
• All forms of deviance were seen in supernatural
  or superstitious terms
• Mental illness and mental retardation seen as
  same condition

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Renaissance (1350-1700 A.D.)

• During this time attention shifted from "other
  world" to man, his nature, dignity, and senses
• spirit of curiosity gave birth to medicine and
  attempts to improve man's condition on earth
• differences in disabilities were noted but
  recognized only the severest disabilities

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Era of Asylum

• lasted approximately 100 years
• concept of equality and the concept of humanism
  arose

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Age of Reason (1700-1800 A.D.)

• Humanism stressed dignity of person
• Phrases were heard such as "all men are created
  equal" and "equality, brotherhood and liberty"
• Individualism instead of Group stressed
• Scientific approach was first used with problems
  relating to disabilities (e.g., MR)

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1800's

• Era of Education
• Time when mass education became emphasis instead
  of education of the few--grew out of 1700's
  concern for enlightenment and individual worth
• During the movement for training
  industrialization shifted man's work to machines
  education became very important

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Movement for Training (1800-1890)

• society became aware of the "slow learner"
• period of optimism-education seen as a "cure"
• significant people
• Louis Braille
• Edouard Seguin
• Guggenbuhl (1940's)

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Era of Indictment

• late 1800's is period of disillusionment and
  pessimism
• recognize the fact that there is no "cure" for
  mental retardation
• research of time indicated that MR and other
  behavior disorders were prime factors in crime
  and degradation in country

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1900's

• time of Measurement (1890-1919 A.D.)
• first mental test was devised (Cattell)
• first special class was founded in the U.S. in
  Providence, RI in 1896
• first program to prepare special education
  teachers developed at NY University (1906)
• Significant people
• Maria Montessori
• Lewis Terman

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Time of Social Control (1900-1930)

• publication of 1912 research study of the
  Kallikak family by Goddard States
• era overlapped the Era of Measurement and Social
  Control

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History of Intelligence Testing

• Head Circumference (Francis Galton 1880) first
  attempts to measure intelligence
• Binet-Simon (Alfred Binet 1909) first
  intelligence test
• comissioned by French gov to separate children
  into vocational vs academic schooling
• did not design test to measure intelligence
• created concept of mental age (MA)

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Psychological Measurement in the 19th Century

• Interest in science and measurement
• Emergence of psychology as an experimental and
  quantitative science
• Interest in hereditary and neurological
  (measurable) basis of cognitive abilities
  (Galton)

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History of Psychological Testing

• Basis of psychological testing
• The significance of individual differences
• Why?
• Interest in performance of professionals
• Chinese system (2200 BC)
• 19th century Europe

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Psychological Measurement in the 20th Century

• Public education and availability of limited
  funds
• Needs of the military for allocating personnel
  (WW I)

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The History of IQ testing

• First IQ tests developed by Alfred Binet
• Alfred Binet and Theodore Simon
• 30 items of increasing difficulty - 1905
• Revision 1908 age specific versions
• These were developed to identify children who
  needed special education -
• Binet believed that IQ could be increased by
  education

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The history of IQ testing

• Early IQ tests gave estimate of childrens MENTAL
  age by comparing their performance on various
  tasks with performance of children at various
  ages

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The history of IQ testing

• calculated as
• IQ Mental Age
• Chronological age x 100
• Nowadays NORM referenced.. that is the average
  performance of a group is calculated, then
  individual comparison

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Henry Herbert Goddard

• Definition of Intelligence
• "our thesis is that the chief determiner of
  human conduct is a unitary mental process which
  we call intelligence that this process is
  conditioned by a nervous mechanism which is
  inborn that the degree of efficiency to be
  attained by that nervous mechanism and the
  consequent grade of intelligence or mental level
  for each individual is determined by the kind of
  chromosomes that come together with the union of
  the germ cells That it is but little affected by
  any later influences except such serious
  accidents as may destroy part of the mechanism"
  (Goddard, 1920, p. 1).

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Henry Herbert Goddard (1866-1957)

• Major Contributions
• Translated the Binet-Simon intelligence scale
  into English (1908)
• Distributed 22,000 copies of the translated Binet
  scale and 88,000 answer blanks across the United
  States (1908-1915)
• Established the first laboratory for the
  psychological study of mentally retarded persons
  (1910)
• Helped to draft the first American law mandating
  special education (1911)
• Strongly argued the hereditarian position

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Henry Herbert Goddard
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Stanford-Binet Intelligence Scale

• Lewis Terman (1916-72) first U.S. intelligence
  test
• Interested in gifted children
• translated and modified Binets scale
• Heavy reliance on vocabulary/language skills
• incorporated old items from the Binet scale, plus
  some new items
• poorly standardized on 1000 children and 400
  adults who were not selected with care

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Lewis Terman (1916-72)

• Developed Intelligence Quotient
• IQ (MA/CA)100
• MA Mental Age CA Chronological Age

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1916 Stanford-BinetSample Items for 12 yr olds
Practical Problem Solving
Vocabulary
Grammar

• Orange.
• 45. Sportive.
• 80. Exaltation.
• 92. Theosophy

• FOR THE STARTED AN WE COUNTRY EARLY AT HOUR
• TO ASKED PAPER MY TEACHER CORRECT I MY
• A DEFENDS DOG GOOD HIS BRAVELY MASTER

Interpretation
Similarities
Memory

• Snake, cow, sparrow
• Book, teacher, newspaper
• Wool, cotton, leather

3-1-8-7-9 6-9-4-8-2 5-2-9-6-1
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A brief history of intelligence testing

• The 1937 revision of the scale was improved
• It had wider range (more room on the floor floor
  and ceiling)
• It had two parallel forms to permit re-testing
• It was standardized on a carefully selected
  population, of 100 children in each six-month
  interval from 6 to 14 years, and 100 in each year
  from 15 to 18, with control of sex, selected from
  17 different communities
• Alas, they were all white and (therefore) above
  average SES
• The test was re-normed in 1960 and 1972, and
  revised completely in 1986 (SB-IV)

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IQ testing in the USA

• In the USA strong supporters of IQ testing were
  scientists who believed that IQ is MAINLY
  genetic, and that society should breed a superior
  group of people
• (This is called eugenics)

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• Army Alpha/Beta IQ Test (1917) designed for WWI
  recruits
• Assumed to be testing native intelligence
• Assumed intelligence and literacy independent
• Alpha for literates Beta for illiterates and
  non-English speakers
• Alpha subtests Oral Directions Arithmetic
  Practical Judgment Analogies Disarranged
  Sentences Number Series Information
• Beta subtests Memory Matching Picture
  Completion Geometric Construction

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Army Alpha Results by Years of Education
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Army Alpha Results by Years of Education
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Army Beta Results by Years of Education
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S J Gould - A Nation of Morons

• YERKES said that
• These tests measure
• NATIVE INTELLECTUAL ABILITY
• in other words intelligence which was unaffected
  by culture or educational opportunities

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S J Gould - A Nation of Morons

• Gould reports many problems in the administration
  of the tests
• Illiterate men were allocated to the Alpha
• The queues for the Beta became so long that some
  men were reallocated to the Alpha
• Many who failed the Alpha were never recalled

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S J Gould - A Nation of Morons

• The BETA test still required men to use pencils
  and paper - and many had never been educated at
  all
• Gould suggests that all the results should be
  viewed with scepticism

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S J Gould - A Nation of Morons

• However the results were used by the army and had
  great impact - mental testing became..
• scientifically established
• by 1921 commercial and educational establishments
  were using the tests

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Test conclusions

• The average mental age of white American adults
  stood at 13
• It was possible to grade European immigrants by
  their country of origin.
• People of Northern Western Europe higher than
  the Slavs who were higher than people of southern
  Europe
• Black people scored lowest of all
• These facts were used to provide a genetic
  explanation for the differences

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S J Gould - A Nation of Morons

• Carl Brigham (Yerkes colleague)
• Explained the differences in terms of racial
  superiority
• we notice the Einsteins of the world BECAUSE
  they are exceptional for their Jewish race

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S J Gould - A Nation of Morons

• Why is this not true?
• Immigration from different parts of Europe took
  place at different times
• The most recent immigrants scored worse on the
  written tests .. If native IQ was being measured
  written English should have NO effect
• Test scores rose with length of stay in the USA
• Those who had been in the USA longer were more
  familiar with American customs products

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S J Gould - A Nation of Morons

• Brigham
• argued that it was a sign of intelligence to
  emigrate to the USA and that the brightest came
  sooner!!
• Later immigrants were progressively more stupid

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S J Gould - A Nation of Morons

• Brigham
• argued that it was a sign of intelligence to
  emigrate to the USA and that the brightest came
  sooner!!
• Later immigrants were progressively more stupid

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S J Gould - A Nation of Morons

• Despite the evidence IQ tests took hold
• 1924 US Congress passed the Immigration
  Restriction Act
• The Act set quotas for immigration to the US
  based on figures 30 years earlier when
  immigration from Southern Eastern Europe was low

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S J Gould - A Nation of Morons

• Gould called this -
• A victory for scientific racism
• During the next 20 years conditions in eastern
  Europe worsened for Slavs and Jews
• (The Nazi years)

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S J Gould - A Nation of Morons

• Gould estimates that
• Immigration quotas barred up to 6 million people
  from entering the USA

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S J Gould - A Nation of Morons

• There is still no good evidence to suggest that
  IQ differences are the result of genetic
  differences

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S J Gould - A Nation of Morons

• There is still no clear operational definition of
  intelligence
• Both race and IQ are political rather than
  biological facts
• (Socially constructed)

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• Weschler Intelligence Scale (David Weschler,
  1939-81) designed to show subtest scores
• Less reliant on language/vocabulary skills
• Contains Verbal and Performance subtests
• Performance compared to same age peers raw
  score has different interpretation depending on
  age
• Designed widely used test for adults (WAIS),
  children (WISC), and preschoolers (WPPSI)

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WAIS-R Testing kit
Testing Booklet
Puzzle Pieces
Story Cards
Block Design
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Other intelligence tests

• There are myriad of other tests of intelligence
  including
• British Ability Scale / Differential Ability
  Scale (DAS)
• Peabody Picture Vocabulary Test (PPVT-R)
• Columbia Mental Maturity Scale (CMMS)
• Ravens Progressive Matrices
• many more
• - Some allow group testing, by using
  closed-choice formats, allowing for mass screening

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Matrices Example Item
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The IQ Controversy

• On average, African-Americans score 10-15 points
  lower on IQ tests than Whites

Used by some to argue for superiority of Whites
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Conclusion to IQ Controversy

• Difference in scores is not due to bias in test
  construction or administration
• Difference in scores is not due to between group
  genetic differences
• Difference in scores is partly due to
  socio-economic class differences
• Differences may be due to cultural and caste
  type factors (racism, societal expectations) -
  still being investigated

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Are all intelligence tests the same?

• Ideally IQ scores obtained with different
  instruments should be identical
• In reality, the instrument makes a difference A
  Wechsler IQ may not be identical to a
  Stanford-Binet IQ
• It is important to specify the instrument

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Can't we make intelligence tests the same?

• Distributional characteristics should make
  interchanging IQ scores easy
• Alas, intelligence is not perfectly normal
• there is a hump at the bottom due to many factors
  which impinge on intelligence in early
  development
• Some have argued that assortative mating has
  flattened the distribution ( more very low and
  high scores than normal)

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Does IQ matter?

• Terman Oden (1959) followed ultra-high IQ
  children (IQ gt 140) for 40 years
• The gifted children were heavier at birth
  walked, talked, and matured earlier their
  general health was better they earned more
  degrees and more money
• However, none went on to become super-successful
  Einstein-types
• Some suggested the positive findings might be due
  to selection bias, since the initial selection
  was based on teacher ratings
• Esquire magazine's "the smartest people in
  America"
• Marilyn Von Savant and her mistakes

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Is IQ innate?

• The literature on IQ heritability is huge and
  controversial
• Heritability in IQ has been estimated between
  0.50 and 0.72 ( 50 - 72 of variability is due
  to genes)
• The best evidence comes from twin studies (ie.
  Bouchard, 1984)
• IQ of identical twins reared apart (even in very
  different circumstances) correlate almost as high
  as those of identical twins reared together
• Honzik (1957) showed almost no correlation
  between IQ of adopted children and IQ of their
  adoptive parents

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Is IQ due to environment?

• However, children reared under conditions of
  little human contact can show huge improvements
  (30-50 IQ points) after being placed in normal
  environments
• Jensen (1977) tested the hypothesis of cumulative
  effects of environmental disadvantage,
  hypothesizing that older deprived children should
  do worse on IQ tests than their younger siblings
• He found some support for this hypothesis- about
  1 point per year for ten years between 5 and 16
  years of age, estimated to be higher if earlier
  years were included
• Disadvantaged adoptees into advantaged homes
  often out-perform their pre-adoptive peers (Scarr
  Weinberg, 1983)

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Is IQ due to environment?

• A purely innate general intelligence should be
  stable over generations
• Intelligence is not stable
• Standardization samples major IQ tests between
  1932 and 1981 tended to be higher than their
  predecessors
• Overall, humankind appears to have picked up
  nearly 14 IQ points in the last century
• Similar observations have been made in other
  countries using other tests
• However, I note that this does not seem to have
  stopped humankind from engaging on a huge scale
  this century in some dangerously stupid
  behaviors

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Is IQ due to environment?

• "psychologists should stop saying that IQ tests
  measure intelligence. They should say that IQ
  tests measure abstract problem-solving ability
  (APSA), a term that accurately conveys our
  ignorance. We know that people solve problems on
  IQ tests we suspect that those problems are so
  detached, or so abstracted from reality, that the
  ability to solve them can diverge over time from
  the real-world problem solving ability called
  intelligence thus far we now little else."
• Flynn, J.R. (1987). Massive IQ gains in 14
  nations What IQ tests really measure,
  Psychological Bulletin, 101, 88, 171-191.

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• Modern IQ Test Design
• Reliability (over time)
• Test-retest
• Internal consistency (items hang together)
• Validity (what it measures)
• Content (face validity)
• Criterion (relationship with other knowns)
• Construct (ability to differentiate)

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Want to learn more about intelligence? A
comprehensive exploration of intelligence
theories throughout history - from Plato to
Jensen - is available at http//www.indiana.edu/
intell/map.html