History of IQ testing

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History of IQ testing
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History of IQ testing

• Before IQ Testing Began
• Francis Galton (1822-1911)
• The Early IQ
• Alfred Binet (1857-1911)
• Charles Spearman (1863-1945)
• Henry Goddard (1865-1957)
• Lewis Terman (1877-1956)

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History of IQ Testing

• Testing in the Military
• Terman, Goddard and Yates
• 1937 Revision
• Other Theories
• David Wechsler
• Howard Gardner and Multiple Intelligence

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History of IQ testing

• The Modern IQ test
• 1960 Revision
• 1972 Revision
• 1986 Revision

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What do the Scores Mean?

• Intelligence Interval
• 40-55
• 55-70
• 70-85
• 85-115
• 115-130
• 130-145
• 145-160
• 160

• Cognitive Designation
• Mentally Disabled (less than 1)
• Learning Difficulty (2.3)
• Below Average
• Average (68 )
• Gifted
• Genius (2.3 )
• Extraordinary Genius (less than 1)
• Unmeasurable Genius

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Reliability

• Intelligence tests are very controversial
• Reliability vs. Validity
• Modern Intelligence tests are quite reliable
• Reliability often measured by administering
  similar forms of a test on 2 occasions

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Reliability

• WAIS-III
• Internal Test-Retest reliabilities of the full
  scale verbal IQs average about .95 or higher
• The other 3 index scores the Performance IQ
  tend to have somewhat lower reliabilities,
  averaging about .90
• Generally, reliabilities for performance
• subtests are lower than for verbal subtests
• Stanford-Binet fourth edition
• Reliability of Composite score is very high
• Various estimates being in the mid- .90s
• Area scores are generally reliable, subtests have
  problematic reliabilities

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Valid Uses of Adult IQ Tests
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Validity Review

• Validity Defined Agreement between a test score
  and the quality it is believed to measure
• Does an IQ test actually give us a valid measure
  or prediction of a certain variable?

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Valid and Non-Valid Uses of IQ Testing in Adults

• When is IQ testing in Adults used correctly?
• When do we overstate the uses of IQ?

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Valid Uses of IQ Testing in Adults

• Recent Study
• IQ scores correlation to other Cognitive tests
• Entire Spectrum of Intelligence
• Scholastic Problems
• Has shown to predict job success better than
  random selection.
• 1939 New York City Police Force
• Follow up testing
• Individuals with Disabilities
• Research

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When do we Overstate the Uses of Adult IQ?

• What IQ really measures
• Certain Abilities
• Does it Predict Job or Economic Success?
• Higher IQ more Success
• Other variables held constant
• Same IQ score
• Different Socioeconomic background
• Different levels of schooling

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When do we Overstate the Uses of Adult IQ?

• Does it Predict Job or Economic Success?
  (continued)
• Manager Observations
• Higher IQ more advanced skills?
• Job Success
• First few months higher IQ outperforms
• 4 or 5 years

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Valid Uses of IQ Testing in Adults

• Be careful what we give IQ credit for.
• Do Not jump to conclusions
• IQ cannot predict beyond what it is actually
  testing

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Test Bias

• If the misery of our poor be caused not by the
  laws of nature, but by our institutions, great is
  our sin. Darwin

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Early Testing Bias

• Craniometry- Paul Broca
• Used in the 19th century to rank races by brain
  size.
• What craniometry was for the 19th century,
  intelligence testing is for the 20th century.
• It assumes that intelligence is a single, innate,
  heritable, and measurable thing.

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Stanford Binet

• Binet rejected the hereditarian interpretation
  and only wanted to use the test as a device to
  identify children in need of special help.
• Binet refused to define his scores as
  intellegence.
• Original test was too language dependent.

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H.H. Goddard

• H.H. Goddard- First to use and interpret Binets
  scale in America.
• Goddard misinterprets.
• Unilinear scale of intelligence.
• Feeble mindedness.
• High grade defectives.
• Morons

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What is Intelligence?

• No two definitions are the same
• Culture
• Stanford-Binet today

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Nurture vs Nature

• What causes variation in intelligence?
• Nurture camp
• Nature camp
• Zeitgeist Pendulum
• Herrstein and Murray
• Interaction between genetics and environment

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Further Reading

• Gould, S.J. The Mismeasure of Man.
• Ridley, M. Nature via Nurture

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Famous IQs

• Leonardo da Vinci 220 OR 190 OR 180 
• William Shakespeare 190 
• Albert Einstein 190 OR 160 
• Plato 180 OR 170 
• Napoleon 180 OR 145
• Pablo Picasso 175 
• Bill Gates 173 OR 160 

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Famous IQs

• Confucius 170 
• Norman Schwarzkopf 170 
• Marilyn Monroe 163 
• Mahatma Gandhi 160 
• Richard Nixon 143 
• Charlie Chaplin 140 
• Bill Clinton 140 

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Famous IQs

• Paul Hogan 140 
• Madonna 140 
• Shakira 140 
• Arnold Schwarzenegger 135 
• Nicole Kidman  132 
• Walt Disney 123 
• Average person 90 to 110
• Koko the trained gorilla 90 
• George Bush 91