INTELLIGENCE Chapter 8

What is Intelligence? Typical Definitions 1.mental abilities needed to select, adapt to, and shape environments 2. abilities to: –profit from experience –solve problems –reason effectively –meet challenges and achieve goals –Formal definition proves elusive.

Is intelligence a single reasoning ability? Charles Spearman’s g-factor (general intelligence) –Speed of mental processing Separate reasoning skills – Robert Sternberg –Analytical, practical, creative (Triarchic) Multiple abilities – Howard Gardner –Linguistic, mathematical, musical, kinesthetic, intrapersonal, interpersonal, spatial, naturalist

Origins of IQ Score (MA/CA) x 100 MA = Mental Age –a measure of intelligence test performance devised by Binet where a given level of test performance is represented by the average age of children who perform at that level. –(For example, a child who does as well as the average 8-year-old is said to have a mental age of 8.) CA = Chronological Age, or the age of the test taker

Intelligence Tests Most popular – Wechsler 1939 WAIS-IV – adults –Wechsler Adult Intelligence Scale WISC-IV – children –Weschler Intelligence Scale for Children WPPSI-III - preschoolers –Wechsler Preschool & Primary Scale of Intelligence Stanford - Binet

Assessing Intelligence –Standardization –Today meaningful IQ scores are defined by comparison with the performance of a pretested “standardization group” –Normal Curve –the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes including IQ –most scores fall near the average; fewer and fewer scores lie near the extremes

The Normal Curve Ninety-five percent of all people fall within 30 points of 100 Number of scores Wechsler intelligence score Sixty-eight percent of people score within 15 points above or below 100

Is intelligence inherited? Partially – This is a nature-nurture question. Are differences in ethnic group averages hereditary? –No. this is best explained culturally.

Plant-Pot Analogy

Early Interventions High-quality center-based interventions improve intelligence & school achievement –Effects strongest for poor children with uneducated parents –Positive effects linger into adolescence, but get smaller –Effects best sustained where programs continue into middle school

Tests of Infant Intelligence Less verbal, more perceptual- motor Do not correlate well with later measures of IQ Often called DQ (Developmental Quotient)

Tests of Infant Intelligence Gesell (1934) detect abnormal infants for adoption agencies –Motor, language, adapative, personal- social Bayley Scales of Infant Development (1969) –Mental, motor & behavior measures –Diagnose developmental delays 1 to 42 mos.

Fagan Test of Infant Intelligence (1992) Encoding attributes Detecting similarities & differences among objects Forming mental representations Retrieving mental representations

Fagan Test of Infant Intelligence (1992) Works well across cultures Predicts intelligence in childhood & adolescence Quicker habituation & more looking in dishabituation reflects more effective information processing.

Stability of Intelligence Using groups of different ages (6, 8, 10, & 18), get high correlations ( ) across ages 2-18 One study testing the same children between the ages of 2 ½ & 17 found changes of up to 40 points in one-third of them (average range = 28 points)

Intelligence in Adulthood Horne (1980s) Cross sectional Groups differed in educational opportunities Problem of cohort effects Found fluid intelligence to decline; crystallized intelligence not to

Changes in Mental Abilities in Adulthood Crystallized intelligence: skills that use accumulated knowledge & experience, good judgment & mastery of social conventions. –IQ test: vocabulary, general information, logical reasoning, verbal analogy –These skills maintain or increase.

Changes in Mental Abilities in Adulthood Fluid intelligence: detecting relationships among stimuli, speed of processing, working memory; abstract reasoning –IQ test: number series, spatial visualization, picture sequencing –These skills decline from middle adulthood.

The Seattle Longitudinal Study Midlife is a period of peak performance on 5 abilities.. Vocabulary Verbal memory Number Spatial orientation Inductive reasoning Perceptual speed drops from the 20s K. Werner Schaie

Changes in IQ Test Performance in Adulthood Cognitive mechanics: neurological hardware of the brain; affected by biology & health; prone to decline with age Cognitive pragmatics: skills, comprehension; cultural experience; may improve with age Paul Baltes (1990s; 2000s)

Changes in IQ Test Performance Many studies show that crystallized intelligence increases, fluid processing speed declines. General Conclusion: Declines are due to a general slowing of the Central Nervous System. There are large individual differences.

Use It or Lose It Factors correlating with less decline, better performance on cognitive tests: above-average education highly complex occupations stimulating leisure pursuits better social situation absence of disease