Intelligence and the Assessment of Intelligence

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Intelligence and the Assessment of Intelligence
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Francis Galton

• Father of the study of individual differences

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Early History of Testing

• Father of IQ testing
• Intelligence test quantification of mental
  functioning
• Binet Scale first intelligence test
• Developed concept of mental age
• Viewed intelligence as malleable

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Testing Moves to the United States Henry Goddard

• Translated Binet scales for Vineland residents
• Widely distributed the Binet Scale

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Testing in the United States Lewis Terman

• Revised Binets Scales
• Adapted items for U.S.
• Added new items
• Established new age norms
• Extended the upper age limit
• Adopted idea of IQ quotient
• Resulting Scale Stanford-Binet Scale

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Intelligence Quotient

• IQ Mental age/Chronological Age X 100
• IQ ratio enables direct comparison of children of
  different ages

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Changes in Conceptualizations of Intelligence
Binet - Terman

• Binet intelligence malleable
• Goddard and Terman intelligence is inherited and
  stable

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William Stern

• Developed the IQ quotient that was adopted by
  Terman

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Robert Yerkes

• Developed group intelligence test to assess army
  recruits
• Results used to screen, classify, and assign

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Members of the Committee on the Psychological
Examination of Recruits
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David Wechsler

• Designed Wechsler scales
• Measures of verbal and nonverbal abilities

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The Wechsler Scales

• Wechsler Intelligence Scale for Children
• (WISC-R)
• Wechsler Adult Intelligence Scale (WAIS)
• Wechsler Preschool and Primary Scale of
  Intelligence (WPPSI)

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Charles Spearman

• From emphasis on testing to emphasis on
  understanding intelligence
• G Factor (general ability)

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L.L. Thurstone

• Accepted the hypothesis of a general factor
• Disputed the importance of the g factor
• Identified 7 primary mental abilities

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Raymond Catell

• Suggested that G had two components fluid and
  crystallized intelligence
• Fluid primary reasonability ability
• Crystallized acquired knowledge

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Guildford

• Parted with the notion of a general factor
• Proposed that intelligence is comprised of many
  (120) separate abilities

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Gardner

• Proposed a theory of multiple intelligences
• Linguistic
• Musical
• Logical-mathematical
• Spatial
• Bodily kinesthetic
• Personal

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Sternberg

• Triarchic theory of intelligence
• Academic
• Practical
• Creative

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Developmental Conceptualization of IQ Jean Piaget

• Cognitive abilities develop through an
  interaction of developing brain and childs
  experiences

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Stages of Cognitive Development

• Sensorimotor (Birth to 2 years)
• Preoperational (2-7years)
• Concrete operations (7-11 years)
• Formal Operations (11 years to adulthood)

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Sensorimotor Period

• The Infants major cognitive tasks centers
  around
• Sensations seeing and hearing
• Motor activities kicking, sucking, and reaching
• Object permanence is acquired at the end of this
  stage

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Preoperational Period

• Development of language
• Egocentrism

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Concrete Operational Period

• Conservation
• Increased logical thinking

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Formal Operational Period

• Abstract reasoning
• Form and test hypotheses

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Cognitive Development

• See video demonstrating the four stages of
  cognitive development

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Current Intelligence Testing

• Despite changes in conceptualization of
  intelligence from one factor to multiple factors,
  current IQ tests have not outgrown the G factor
  of Spearman
• The IQ score, which is still widely used, implies
  an assessment of general ability.

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The Wechsler Scales

• Verbal Subtests
• Information
• Vocabulary
• Arithmetic
• Similarities
• Comprehension
• Digit Span

• Performance Subtests
• Picture Completion
• Picture Arrangement
• Block Design
• Object Assembly
• Digit Symbol

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Verbal Subtests

• Information culturally acquired info
• Vocabulary general verbal intell.
• Arithmetic numerical reasoning
• Similarities abstract reasoning
• Comprehension social norms
• Digit Span short term memory

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Performance Subtests

• Picture Completion visual concentration and
  nonverbal general information
• Picture Arrangement ability to plan, interpret
  and anticipate in social context
• Block Design perceptual organization, spatial
  visualization and abstract concentration
• Object Assembly visual motor organ., synthesis
• Digit Symbol visual memory

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Similarities

• In what way are an orange and a banana alike?

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Vocabulary

• Bed
• Ship
• Penny

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Digit Span

• Demonstrate

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Picture Completion
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Block Design
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Object Assembly
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Digit Symbol Coding
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Picture Arrangement
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Wechsler Scales Clinical Use

• Estimation of general intelligence (correlates
  with academic success and occupational status)
• Examine the discrepancy in performance between
  verbal and performance subtests
• Examine the variability among subtests

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Controversies Race and IQ

• Average IQ score differ for various racial and
  ethnic groups
• Asian Americans
• Whites
• Latina
• African Americans

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Race and IQ Controversy Key Figures

• Genetics
• Goddard
• Pearson
• Terman
• Jensen Harvard Educational Review
• Hernstein and Murray Under the Bell Curve
• Shockley

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Aruther Jensen
Those who would accord any treatment to
individuals solely by virtue of their race will
find no rational support in any of the scientific
findings from psychological testing or present
day theories of differential psychology.
William Shockely
Nature has color coded groups of individuals so
that statistically reliable predictions of their
adaptability to intellectually rewarding and
effective lives can easily be made and profitably
be used by the pragmatic man-in-the-street.
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Explanations of Ethnic Differences in IQ Scores

• Tests are not valid
• Economics
• Genetics
• Most controversial

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Genetics

• Genetics
• Heritability estimates for IQ is about .50 in a
  population

• Environment
• Like other traits, IQ is changeable (height for
  example).
• Educational experiences affect IQ
• IQ scores have increased over the years
  (nutritional factors, increasing access to
  information)

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