Intelligence

Meredyth DanemanPSY100

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 = 150

12yr 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 --- .35 .45 .41

Weights --- --- .70 .52

Pullups --- --- --- .37

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

.