IntelligenceIntelligence

Evolution of the Concept of Evolution of the Concept of IntelligenceIntelligence

Chinese tests for civil service.Chinese tests for civil service. Galton (mid 1800s)—speed of sensory Galton (mid 1800s)—speed of sensory

discrimination reflected intelligence.discrimination reflected intelligence. Binet’s work (late 1800s) in France.Binet’s work (late 1800s) in France. Stanford University—the Stanford-Binet Stanford University—the Stanford-Binet

Test of Intelligence (early 1900s).Test of Intelligence (early 1900s).

What did IQ mean What did IQ mean originally?originally?

Chronological AgeChronological Age ( (CACA): Child’s ): Child’s actual age in years.actual age in years.

Mental AgeMental Age ( (MAMA): The age, in years, ): The age, in years, of the average child who could solve of the average child who could solve these same problems.these same problems.

Intelligence QuotientIntelligence Quotient ( (IQIQ): Measures ): Measures the proportion that the mental age is the proportion that the mental age is of the chronological age.of the chronological age.

IQ = MA / CA times 100IQ = MA / CA times 100

Calculating IQ originallyCalculating IQ originally If a child is 10 years old and does If a child is 10 years old and does

questions like the average 7 year old, i.e., questions like the average 7 year old, i.e., has a mental age of 7 years,has a mental age of 7 years,

IQ = 7/10 times 100 = 70IQ = 7/10 times 100 = 70 If a child is 10 years old and does If a child is 10 years old and does

questions at the level of the average 12 questions at the level of the average 12 year old, i.e., has a mental age of 12, year old, i.e., has a mental age of 12,

IQ = 12/10 times 100 = 120IQ = 12/10 times 100 = 120

If the MA = CA, IQ will be 100.If the MA = CA, IQ will be 100. If the MA < CA, IQ will be below 100.If the MA < CA, IQ will be below 100. If the MA > CA, IQ will be above 100.If the MA > CA, IQ will be above 100.

IQ TestsIQ Tests Originally based on questions that were Originally based on questions that were

thought to represent tasks thatthought to represent tasks that childrenchildren would have to be able to accomplish to be would have to be able to accomplish to be successful in school.successful in school.

Developed to predict success in school.Developed to predict success in school. Still do that very well—an excellent Still do that very well—an excellent

predictor of academic success.predictor of academic success. Many forms of modern IQ tests do Many forms of modern IQ tests do notnot

predict success in life. IQ scores now are predict success in life. IQ scores now are thought to reflect the amount of thought to reflect the amount of ‘intelligence’ an individual has.‘intelligence’ an individual has.

Many Perspectives on Many Perspectives on IntelligenceIntelligence

Now accepted that no one IQ test will Now accepted that no one IQ test will measure all aspects of what we call measure all aspects of what we call intelligence.intelligence.

Any IQ test will reflect the definition of Any IQ test will reflect the definition of intelligence and the culture of the designer, intelligence and the culture of the designer, e.g.,e.g.,– Cattell’s two factors: Fluid and crystallized Cattell’s two factors: Fluid and crystallized

intelligence.intelligence.– Multiple factors: Multiple factors:

General and specific intelligences—Spearman’s ‘g’.General and specific intelligences—Spearman’s ‘g’. Sternberg’s analytic, creative, and practical Sternberg’s analytic, creative, and practical

intelligences.intelligences. Gardner’s Theory of Multiple IntelligencesGardner’s Theory of Multiple Intelligences

Cattell’s Two FactorsCattell’s Two Factors Fluid intelligenceFluid intelligence

– Ability to deal with what are essentially new Ability to deal with what are essentially new problems. problems.

– Requires fluency, speed, and flexibility.Requires fluency, speed, and flexibility. What comes next ? 3, 8, 12, 15, 17, ?What comes next ? 3, 8, 12, 15, 17, ?

– Seems to drop off with age, starting in middle Seems to drop off with age, starting in middle adulthood.adulthood.

Crystallized intelligenceCrystallized intelligence– Based on stored knowledgeBased on stored knowledge

6 x 7 – 4 x 5 = ? 6 x 7 – 4 x 5 = ?

– Continues to increase as long as environment Continues to increase as long as environment in stimulating. in stimulating.

Spearman and General Spearman and General IntelligenceIntelligence

All tests that are used to measure All tests that are used to measure intelligence are correlated to some degree.intelligence are correlated to some degree.

This provides evidence for an underlying This provides evidence for an underlying general intelligence ‘g’, required for every general intelligence ‘g’, required for every mental task.mental task.

Higher ‘g’ means an advantage on all Higher ‘g’ means an advantage on all intellectual tasks, lower ‘g’ means doing intellectual tasks, lower ‘g’ means doing poorly on many of these tasks.poorly on many of these tasks.

However, the correlations are not perfect so However, the correlations are not perfect so there must be other specific intelligences there must be other specific intelligences being measured: sbeing measured: s11, s, s22, s, s33, . . ., . . .

Gardner’s Theory of Multiple Gardner’s Theory of Multiple IntelligencesIntelligences

MusicalMusical Recognize & compose musical pitch, tone, & Recognize & compose musical pitch, tone, & rhythm rhythm

VerbalVerbal Language mastery, self-expressing rhetorically & Language mastery, self-expressing rhetorically & poeticallypoetically

MathematicalMathematical/Logical/Logical

Detecting patterns, deductive reasoning, Detecting patterns, deductive reasoning, logical thinking logical thinking

SpatialSpatial Using mental images to solve problems Using mental images to solve problems

KinestheticKinesthetic Coordinate own bodily movements Coordinate own bodily movements

IntrapersonalIntrapersonal Understanding self, recognizing strengths & Understanding self, recognizing strengths & weaknesses weaknesses

InterpersonalInterpersonal Understanding people, leading, Understanding people, leading, communicating communicating

IQ TestsIQ TestsWhat Does IQ Mean for Adults?What Does IQ Mean for Adults? Cannot develop a set of questions that will Cannot develop a set of questions that will

discriminate the one age of adult from discriminate the one age of adult from another.another.

Instead, questions are developed based on Instead, questions are developed based on some theoretical position.some theoretical position.

When many normal adults are tested When many normal adults are tested (standardization sample) the scores form a (standardization sample) the scores form a normal distribution.normal distribution.

The mean of the test is considered to The mean of the test is considered to represent an IQ of 100. Above will be higher represent an IQ of 100. Above will be higher than 100, below will be lower than 100.than 100, below will be lower than 100.

Is Intelligence Inherited?Is Intelligence Inherited? Twin StudiesTwin Studies

– Identical (monozygotic) twins—identical Identical (monozygotic) twins—identical genes.genes.

– Fraternal twins (dizygotic)—no more alike Fraternal twins (dizygotic)—no more alike than siblings, share about 50% of their than siblings, share about 50% of their genes.genes.

– Would expect identical twins to be more Would expect identical twins to be more alike than fraternal twins on any inherited alike than fraternal twins on any inherited characteristic.characteristic.

– If intelligence is inherited, there should be If intelligence is inherited, there should be higher correlations between scores of higher correlations between scores of pairs of identical twins than for pairs of pairs of identical twins than for pairs of fraternal twins.fraternal twins.

Is Intelligence Inherited?Is Intelligence Inherited? Adoption StudiesAdoption Studies

– If genes are an important determinant in If genes are an important determinant in characteristics such as IQ:characteristics such as IQ: Children who are raised apart from their Children who are raised apart from their

biological parents should still be more like biological parents should still be more like their parents. The correlations between IQ their parents. The correlations between IQ scores should be higher than for children scores should be higher than for children and their adopted parents. and their adopted parents.

Identical twins adopted into different homes Identical twins adopted into different homes should still show fairly high correlations should still show fairly high correlations between their IQ scores. between their IQ scores.

Is Intelligence Inherited?Is Intelligence Inherited?

ConclusionConclusion

Genes are an important contributor Genes are an important contributor to level of intelligence.to level of intelligence.

Environment is also an important Environment is also an important contributor to level of intelligence.contributor to level of intelligence.

Within a culture, genes are probably Within a culture, genes are probably more important to explain more important to explain intellectual differences.intellectual differences.

Between cultures, environment is Between cultures, environment is probably more important to explain probably more important to explain these differences.these differences.