Intelligence Meredyth Daneman PSY100

What is Intelligence? abstract reasoning, problem solving, capacity to acquire knowledge memory, mental speed, linguistic competence, mathematical competence, general knowledge, creativity sensory acuity, goal-directedness, creativity what intelligence tests measure

Overview Nature of intelligence Methods to measure intelligence Theoretical approaches Heredity and intelligence

Nature of Intelligence Functional Multi-faceted Culturally Defined

Nature of Intelligence Provisionally define intelligence as: the application of cognitive skills and knowledge to learn, solve problems, and obtain ends that are valued by an individual culture

Intelligence Testing Intelligence tests are measures designed to assess an individual’s level of cognitive capabilities compared to other people in the population

Intelligence Testing (Galton) Sir Francis Galton believed building blocks of intelligence are simple sensory, perceptual, and motor abilities found that these elementary tasks did not correlate with much of anything pioneering statistician – correlation

Intelligence Testing (Binet) Binet believed that a true measure of intelligence is an individual’s performance on complex tasks of memory, reasoning, and comprehension developed the concept of “mental age” or “mental level”

Intelligence Testing A child’s mental age (MA) indicates that he/she displays the mental abilities of a child of that chronological age (CA) a child with a CA of 5 who can answer questions a typical 7-yr old answers, has a MA of 7 a 5-yr old who can answer the questions expected for his/her age but no older, has a MA of 5

Intelligence Testing (Terman) Terman revised the scales: Stanford-Binet intelligence quotient (IQ), a score meant to quantify intellectual functioning to allow comparison among individuals

IQ = (MA/CA) X 100 8yr old performs at level of 12yr old (12/8) X 100 = yr old performs at level of 8yr old (8/12) X 100 = 66 12yr old performs at level of 12yr old (12/12) X 100 = 100

Intelligence Testing (Wechsler) Wechsler developed test that could be used for adults WAIS (adults) WPPSI (children) verbal and performance subtests frequency distribution of IQ scores

Wechsler Intelligence Scales: Verbal IQ

Wechsler Intelligence Scales: Performance IQ

Frequency Distribution of IQ Scores Original IQ formula was useful for assessing children’s test performance, but not adults’ test performance Wechsler remedied the problem by abandoning concept of MA and calculating IQ as an individual’s position relative to peers of the same age on a frequency distribution

The scores on an IQ test form an approximately bell-shaped curve. The curve shown here represents scores on the Wechsler IQ test, with a standard deviation of 15 (15 points above and below the mean, which is 100).

The Extremes of Intelligence Mental retardation: IQ less than 70 about 2% of population 75-90% are in mild to moderate range (IQ 50-70) 10% in severe to profound range (IQ below 50)

The Extremes of Intelligence Giftedness: IQs exceeding 130

Validity & Reliability of IQ Tests Validity: the ability to assess the construct it was designed to measure Reliability: the ability to produce consistent results

IQ Testing: Criticism & Controversy Lack of theoretical basis Are IQ tests culturally biased? Are IQ tests valid?

Approaches to Intelligence psychometric approach information-processing approach multi-component approach

Psychometric Approach The psychometric approach tries to identify groups of items in a test that correlate with one another in order to discover underlying skills or abilities Factor analysis: a statistical procedure for finding patterns of correlations among measures in order to identify underlying factors or mental abilities

Identifying a Common Factor Sprint Weights Pullups Situps Sprint Weights Pullups Situps

Spearman’s Two-Factor Theory general factor or g-factor specific factors or s-factors

Cattell’s Theory Fluid intelligence speed and accuracy for abstract reasoning, especially for novel problems (drawing inferences, finding analogies, recognizing patterns) Crystallized intelligence accumulated knowledge and vocabulary

Thurstone: seven primary abilities word fluency comprehension numerical computation spatial skills associative memory reasoning perceptual speed

Information-Processing Approach tries to understand the processes that underlie intelligent behaviour; e.g., what is general intelligence or “g”? various proposals: working memory capacity retrieving information from long-term memory speed of processing (inspection time)

Theory of Multiple Intelligences (Gardner) Seven intelligences musical bodily/kinesthetic spatial linguistic or verbal logical/mathematical intrapersonal interpersonal

Gardner Savants one island of brilliance Prodigies extraordinary and generally early developing genius in one area, but normal abilities in others

Heredity and Intelligence Evidence for Hereditary Influences twin studies adoption studies

Heredity and Intelligence Evidence for Environmental Influences adoption studies environmental deprivation & enrichment generational change (the Flynn effect)

Flynn Effect IQ has been rising steadily over the industrialized world since 1930s Has to be attributed to environmental factors Hypotheses: reductions in severe malnutrition advances in technology (TV, computers, video games) improved schools, smaller families, better educated and informed parents

Heredity vs. Environment individual differences vs. group differences

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