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What is intelligence?
Think of the smartest people you know. What makes you think they are intelligent?
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The World’s Smartest: Potential and Pitfalls
Child Genius
World’s Smartest Man
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Intelligence
What is intelligence? Are there different types of intelligence? If so, how many? Can intelligence be measured? Not all psychologists agree on the answers
to these important questions
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What Is IQ?
IQ: Intelligence QuotientScore on an intelligence testMeaning has changed over time; also, how
mutable it is and origins of between group differences.
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Intelligence Testing: History Alfred Binet and Theodore Simon
Developed first intelligence test (1904-1911)Identify students who need extra helpTest many normal children at each ageCompare individual’s score to “normal”
scoresMental ageChronological age
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Intelligence Testing: History Lewis Terman (Stanford University)
Developed American version of the Binet-Simon test, called the Stanford-Binet test, for ages 2 to adult
David WechslerWechsler Adult Intelligence Scale (WAIS)Wechsler Intelligence Scale for Children (WISC)Performance and verbal subtests
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Wechsler Adult Intelligence Scale
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Calculating IQ
William SternProblem: people don’t get stupider with age
Modern approachCompare individual to standardized sample
IQ =mental age
chronological agex 100
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The Normal Curve
Population Norming
Mean Standard deviation
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Reliability and Validity
A good test must be valid and reliable Reliability
Test produces consistent results
ValidityTest measures what it is supposed to
The WAIS-III is highly reliable, but is it a valid measure of intelligence?
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IQ and Achievement
IQ tends to be related to achievementHigh school and college gradesJob prestige and salaryMarital stability
However, IQ accounts for only a small amount of the variation in job success
Correlation is not causation Motivation, education, culture are important
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One Intelligence or Many? Charles Spearman
g: general factors: specific factorsIntelligence depends mostly on gFactor analysis
Louis ThurstoneSeparate primary mental abilitiesExamples: verbal comprehension and spatial
visualization
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One Intelligence or Many? Raymond Cattell and John Horn
Crystallized intelligenceFluid intelligence
AgingCrystallized intelligence doesn’t sufferFluid intelligence tends to decreaseDifferent aging effects support the distinction
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One Intelligence or Many? Carroll’s three-stratum model
Top strata is g, general intelligenceSecond strata includes fluid and crystallized
intelligence with 6 other broad abilitiesThird strata includes 69 specific abilities
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Emotional Intelligence (EI)
Knowing your emotions Managing your feelings Self-motivation Recognizing others’ emotions Handling relationships Women tend to have higher EI than men
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Multiple IntelligencesHoward Gardner (8 or 9 forms of intelligence) 1) Linguistic intelligence: The ability to use language
well. 2) Spatial intelligence: The ability to reason well about
spatial relations. 3) Musical intelligence: The ability to compose and
understand music. 4) Logical-mathematical intelligence: The ability to
manipulate abstract symbols. 5) Bodily-kinesthetic intelligence: The ability to plan
and understand sequences of movements. 6) Intrapersonal intelligence: The ability to understand
oneself. 7) Interpersonal intelligence: The ability to understand
other people and social interactions. 8) Naturalist intelligence: The ability to observe carefully. 9) Existential intelligence: The ability to address “the
big questions” about existence.
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Brain Size and Intelligence Is bigger always better?
Depends more on size of crucial brain areasFemales tend to have smaller brains but equal
IQsCorrelation between size and intelligence is
smallCorrelation is not causation
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IQ and Speed of Processing Is IQ correlated with speed of information
processing?Mixed resultsMany IQ subscales are time, so it is not
surprising that mental processing speed would be related to IQ
Measures of neural conduction are only weakly related to intelligence
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Working Memory and IQ
IQ is correlated with working memoryMany IQ subscales are involve memory, so
it is not surprising that mental processing speed would be related to IQ
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IQ: Genes and Environment Adoption studies
Correlation of IQs for identical twins raised apart is higher than that for fraternal twins and nontwin siblings raised together
An adopted child’s IQ correlates higher with the biological mother’s IQ than with the adoptive mother’s IQ
Strong evidence of the link between genes and IQ
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IQ: Genes and Environment Effects of environment
Stoolmiller (1999) estimated the effects of the environment on IQ to be 57%
MicroenvironmentReaction range
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Group Differences in IQ
Within-group versus between-group differencesGenetics accounts for 72% of IQ variation in
affluent environmentsGenetics accounts for 15% of IQ variation in
impoverished environments Race differences: Why? Test bias Environmental differences Microenvironments Sex differences
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Boosting IQ
The Flynn effectAverage IQ increases 3 points every 10
yearsExplanations?
○ Daily life is more challenging○ Nutrition is better○ Reasoning ability stressed by IQ tests has
gotten better, not IQ itself
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The Pygmalion Effect
Rosenthal & Jacobson“Harvard Test of Inflected Acquisition”Random selection of childrenSelf-fulfilling prophecy
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Educational Programs and IQ Head Start and similar projects
Most show only short-term IQ gainsMost gains evaporate over time
Abecedarian ProjectIntellectual, medical, and nutritional
enrichment5 years before kindergartenLong-term 5-point IQ boost
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Mental Retardation
IQ less than 70
4-7 million Americans
Islands of excellenceKim Peek
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Mental Retardation
Genetic influencesDown syndromeFragile X syndromeAutism
Environmental influencesFetal alcohol syndromeChildhood diseasesExposure to environmental toxinsInadequate medical care
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The Gifted
IQ of 150-180 Prodigies