Intelligence

Evolution of the Concept of Intelligence Chinese tests for civil service. Chinese tests for civil service. Galton (mid 1800s)—speed of sensory discrimination reflected intelligence. Galton (mid 1800s)—speed of sensory discrimination reflected intelligence. Binet’s work (late 1800s) in France. Binet’s work (late 1800s) in France. Stanford University—the Stanford-Binet Test of Intelligence (early 1900s). Stanford University—the Stanford-Binet Test of Intelligence (early 1900s).

What did IQ mean originally? Chronological Age (CA): Child’s actual age in years. Chronological Age (CA): Child’s actual age in years. Mental Age (MA): The age, in years, of the average child who could solve these same problems. Mental Age (MA): The age, in years, of the average child who could solve these same problems. Intelligence Quotient (IQ): Measures the proportion that the mental age is of the chronological age. Intelligence Quotient (IQ): Measures the proportion that the mental age is of the chronological age. IQ = MA / CA times 100

Calculating IQ originally If a child is 10 years old and does questions like the average 7 year old, i.e., has a mental age of 7 years, If a child is 10 years old and does questions like the average 7 year old, i.e., has a mental age of 7 years, IQ = 7/10 times 100 = 70 If a child is 10 years old and does questions at the level of the average 12 year old, i.e., has a mental age of 12, If a child is 10 years old and does questions at the level of the average 12 year old, i.e., has a mental age of 12, IQ = 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 Tests Originally based on questions that were thought to represent tasks that children would have to be able to accomplish to be successful in school. Originally based on questions that were thought to represent tasks that children would have to be able to accomplish to be successful in school. Developed to predict success in school. Developed to predict success in school. Still do that very well—an excellent predictor of academic success. Still do that very well—an excellent predictor of academic success. Many forms of modern IQ tests do not predict success in life. IQ scores now are thought to reflect the amount of ‘intelligence’ an individual has. Many forms of modern IQ tests do not predict success in life. IQ scores now are thought to reflect the amount of ‘intelligence’ an individual has.

Many Perspectives on Intelligence Now accepted that no one IQ test will measure all aspects of what we call intelligence. Now accepted that no one IQ test will measure all aspects of what we call intelligence. Any IQ test will reflect the definition of intelligence and the culture of the designer, e.g., Any IQ test will reflect the definition of intelligence and the culture of the designer, e.g., –Cattell’s two factors: Fluid and crystallized intelligence. –Multiple factors:  General and specific intelligences—Spearman’s ‘g’.  Sternberg’s analytic, creative, and practical intelligences.  Gardner’s Theory of Multiple Intelligences

Cattell’s Two Factors Fluid intelligence Fluid intelligence –Ability to deal with what are essentially new problems. –Requires fluency, speed, and flexibility.  What comes next ? 3, 8, 12, 15, 17, ? –Seems to drop off with age, starting in middle adulthood. Crystallized intelligence Crystallized intelligence –Based on stored knowledge  6 x 7 – 4 x 5 = ? –Continues to increase as long as environment in stimulating.

Spearman and General Intelligence All tests that are used to measure intelligence are correlated to some degree. All tests that are used to measure intelligence are correlated to some degree. This provides evidence for an underlying general intelligence ‘g’, required for every mental task. This provides evidence for an underlying general intelligence ‘g’, required for every mental task. Higher ‘g’ means an advantage on all intellectual tasks, lower ‘g’ means doing poorly on many of these tasks. Higher ‘g’ means an advantage on all intellectual tasks, lower ‘g’ means doing poorly on many of these tasks. However, the correlations are not perfect so there must be other specific intelligences being measured: s 1, s 2, s 3,... However, the correlations are not perfect so there must be other specific intelligences being measured: s 1, s 2, s 3,...

Gardner’s Theory of Multiple Intelligences Musical Recognize & compose musical pitch, tone, & rhythm Verbal Language mastery, self-expressing rhetorically & poetically Mathematical/ Logical Detecting patterns, deductive reasoning, logical thinking Spatial Using mental images to solve problems Kinesthetic Coordinate own bodily movements Intrapersonal Understanding self, recognizing strengths & weaknesses Interpersonal Understanding people, leading, communicating

IQ Tests What Does IQ Mean for Adults? Cannot develop a set of questions that will discriminate the one age of adult from another. Cannot develop a set of questions that will discriminate the one age of adult from another. Instead, questions are developed based on some theoretical position. Instead, questions are developed based on some theoretical position. When many normal adults are tested (standardization sample) the scores form a normal distribution. When many normal adults are tested (standardization sample) the scores form a normal distribution. The mean of the test is considered to represent an IQ of 100. Above will be higher than 100, below will be lower than 100. The mean of the test is considered to represent an IQ of 100. Above will be higher than 100, below will be lower than 100.

Is Intelligence Inherited? Twin Studies Twin Studies –Identical (monozygotic) twins—identical genes. –Fraternal twins (dizygotic)—no more alike than siblings, share about 50% of their genes. –Would expect identical twins to be more alike than fraternal twins on any inherited characteristic. –If intelligence is inherited, there should be higher correlations between scores of pairs of identical twins than for pairs of fraternal twins.

Is Intelligence Inherited? Adoption Studies Adoption Studies –If genes are an important determinant in characteristics such as IQ:  Children who are raised apart from their biological parents should still be more like their parents. The correlations between IQ scores should be higher than for children and their adopted parents.  Identical twins adopted into different homes should still show fairly high correlations between their IQ scores.

Is Intelligence Inherited?

Conclusion Genes are an important contributor to level of intelligence. Genes are an important contributor to level of intelligence. Environment is also an important contributor to level of intelligence. Environment is also an important contributor to level of intelligence. Within a culture, genes are probably more important to explain intellectual differences. Within a culture, genes are probably more important to explain intellectual differences. Between cultures, environment is probably more important to explain these differences. Between cultures, environment is probably more important to explain these differences.