INTELLIGENCE INTELLIGENCE Chapter 8
What is IntelligenceWhat is Intelligence??Typical Definitions1.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 Is intelligence a single reasoning ability?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 ScoreOrigins 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 TestsIntelligence 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 IntelligenceAssessing 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 CurveThe Normal Curve
Ninety-five percent of all people fall within 30 points
of 100
Number of
scores
55 70 85 100 115 130 145 Wechsler intelligence score
Sixty-eight percentof people score within 15 points
above or below 100
Is intelligence inherited?Is intelligence inherited?• Partially – This is a nature-nurture
question.
• Are differences in ethnic group averages hereditary?– No. this is best explained culturally.
Early InterventionsEarly 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 IntelligenceTests 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 IntelligenceTests 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.
FaganFagan Test of Infant Intelligence Test of Infant Intelligence (1992)(1992)
• Encoding attributes
• Detecting similarities & differences among objects
• Forming mental representations
• Retrieving mental representations
FaganFagan Test of Infant Intelligence Test of Infant Intelligence (1992)(1992)
• Works well across cultures
• Predicts intelligence in childhood & adolescence
• Quicker habituation & more looking in dishabituation reflects more effective information processing.
Stability of IntelligenceStability of Intelligence
• Using groups of different ages (6, 8, 10, & 18), get high correlations (+.70 - +.90) 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 AdulthoodIntelligence 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 Changes in Mental Abilities in Adulthoodin 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 Changes in Mental Abilities in Adulthoodin 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 The Seattle Longitudinal StudyStudy
• 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 Changes in IQ Test Performance in AdulthoodPerformance 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 Changes in IQ Test PerformancePerformance
• 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.