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Chapter 9. Intelligence. Defining Intelligence. Intelligence: global capacity to act purposefully, think rationally, and deal effectively with the environment
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Chapter 9 Intelligence
Defining Intelligence • Intelligence: global capacity to act purposefully, think rationally, and deal effectively with the environment • g-factor:general ability factor, or core of general intelligence that involves reasoning, problem-solving ability, knowledge, memory, and successful adaptation to one’s surroundings • Operational definition: operations used to measure a concept; in the case of intelligence, creating an intelligence test
Aptitudes • Aptitude: capacity for learning certain abilities • Special aptitude test: test that predicts whether you will succeed in a single area • Multiple aptitude test: test that measures two or more types of ability • General intelligence test: test that assesses a wide variety of mental abilities
Reliability and Validity • Psychometric test: any measurement of a person’s mental functions • Reliability: a reliable psychometric test must give approximately the same score each time a person takes it • Validity: a valid psychometric should measure what it claims to measure
Objective Testing • Objective test: a test (IQ or otherwise) is objective if it gives the same score when corrected by different people • Test standardization: first, it means standard procedures are used in giving the test and, second, individual test scores are compared to norms, or average scores made by a large group of people like those for whom the test was designed
Testing Intelligence: The Stanford-Binet • Stanford-Binet Intelligence Scale, Fifth Edition (SB5): widely used individual intelligence test, derived directly from Alfred Binet’s first intelligence test; items are age-ranked
SB5: Five Cognitive Factors • Fluid reasoning • Knowledge • Quantitative reasoning • Visual-spatial processing • Working memory
Wechsler Tests • Wechsler Adult Intelligence Test, 4th Edition (WAIS-IV) • Wechsler Intelligence Scale for Children, 4th Edition (WISC-IV) • Like the SB-5, the Wechsler tests yield • a single overall intelligence score • a separate score for performance (nonverbal) intelligence • a separate score for verbal (language- or symbol-oriented) intelligence.
Group Tests • Individual intelligence test: designed to be given to a single person by a trained specialist (e.g., SB5 and the Wechsler tests) • Group intelligence tests can be given to a large group of people with minimal supervision (e.g., Army Alpha, SAT Reasoning Test, American College Test, (ACT), College Qualification Test (CQT))
Intelligence Quotient (IQ) • Mental age: average intellectual performance • Chronological age: person’s age in years • Intelligence index: mental age divided by chronological age, then multiplied by 100 • Average IQ in the USA is 100 • Deviation IQ: scores based on a person’s relative standing in his or her age group; how far above or below average a person’s score is, relative to other scores
Stability of IQ • IQ scores are not dependable until a child reaches age 6 • After age 6, IQ scores become more stable • Fluid intelligence: solving novel problems involving perceptual speed or rapid insight; declines rapidly after middle age • Crystallized intelligence: solving problems using already acquired knowledge—can actually increase or at least decline very little until advanced age
Other Variations in IQ • Normal (bell-shaped) curve: distribution of observed IQ scores; most scores fall close to the average, and very few are found at the extremes • Men and women do not appear to differ in overall intelligence • A strong correlation (about .50) exists between IQ and school grades
Gifted Children • Have a high IQ (usually above 130) or special talents or abilities (play Mozart at age 5) • Gifted or not, successful people are persistent and motivated to learn
Intellectual Disability • An IQ score below 70 and a significant impairment of adaptive behavior together define intellectual disability • Adaptive behavior: basic skills such as dressing, eating, working, hygiene; necessary for self-care
Causes of Intellectual Disability • Familial intellectual disability: mild intellectual disability that occurs in homes that have inadequate nutrition, intellectual stimulation, medical care, and emotional support; accounts for 30-40% of cases • Organic intellectual disability: intellectual disability related to physical disorders
Organic (Physical) Causes of Intellectual Disabilities • Birth injuries: lack of oxygen during delivery • Fetal damage: prenatal damage from disease, infection, or drug use • Metabolic disorders: affect energy use and production in the body • Genetic abnormalities: missing genes, extra genes, or defective genes
Down Syndrome (Trisomy 21) • Most common form of genetic intellectual disability; occurs In 1/800 babies • Down syndrome children have an extra 21st chromosome; genetic problem but not hereditary • Reproductive cells of older parents more prone to errors during cell division • Down children are usually loving and responsive
Fragile X Syndrome • Second most common form of genetic intellectual disability; occurs In 1/3,800 boys • Fragile X is hereditary; sex-linked to x-chromosome and affects boys more often • Fragile X males generally have long, thin faces and big ears and suffer from hyperactivity and attention disorders • They are only mildly intellectually disabled during early childhood, severely intellectually disabled as adults
Phenylketonuria (PKU) • Genetic disease involving lack of an important enzyme, causing buildup of phenylpyruvic acid (a destructive chemical) • Untreated, it leads to severe intellectual disability by age 3
Microcephaly (“Smallheadedness”) • A rare abnormality in which the skull is extremely small or fails to grow • Forces brain to develop in a limited space, causing severe intellectual disability
Hydrocephaly (“Water on the Brain”) • Pressure from excess buildup of cerebrospinal fluid within brain cavities damages brain and enlarges the head • Tube can be implanted to drain fluid from the brain to the stomach and minimize brain damage
Cretinism • Due to an insufficient supply of thyroid hormone • Untreated, will cause stunted physical and intellectual growth • Can be treated with thyroid hormone replacement before permanent damage occurs
Heredity and Environment: Hereditary Influences • Eugenics: selective breeding for desirable characteristics • Suggests that some traits are highly influenced by heredity
Twin Studies • Comparison of characteristics of twins who were raised together or separated at birth; used to identify relative impact of heredity and environment • IQs of identical twins (twins who develop from a single egg and have identical genes) are more similar than IQs of fraternal twins (two separate eggs fertilized at the same time)
Heredity and Environment: Environmental Influences • Children from high socioeconomic status (SES) homes develop higher IQs • Children adopted out of low SES homes experience IQ gains • Flynn effect: dramatic IQ gains made by Western industrialized nations over the last 30 years • Early childhood education programs produce long-term gains in IQ
Heredity and Environment: Conclusion • Most researchers believe that intelligence is a combination of heredity (genes) and environment (upbringing) • Degree of contribution of each is not known yet
The Intelligent Nervous System • People with higher IQs perform faster on reaction time tasks • Reaction time: the time it takes people to respond to a stimulus • Speed of processing: measured with reaction time, which is assumed to reflect the brain’s speed and efficiency
The Intelligent Nervous System (cont’d) • Parts of frontal cortex are larger in people with higher IQs • The same is true for other parts of cortex
Intelligent Information Processing (Perkins) • Three factors determining intelligence • Neural intelligence: speed and efficiency of the nervous system • Experiential intelligence: specialized knowledge and skills acquired over time • Reflective intelligence: ability to become aware of one’s own thinking habits • Metacognitive skills: the ability to manage your own thinking and problem-solving
Artificial Intelligence (AI) • Artificial intelligence (AI): computer programs that perform humanlike problem-solving or intelligent responding • Computer simulations: programs that attempt to duplicate human behavior, especially thinking, problem-solving, or decision-making • Expert systems: computer programs that respond as a human expert would
Multiple Intelligences: Howard Gardner • Multiple intelligences: theory posed by Howard Gardner that states we have several specialized types of intellectual ability
Gardner’s Theory of Eight Multiple Intelligences • Language: linguistic abilities; used by writers, lawyers, comedians • Logic and math: numeric abilities; used by scientists, accountants, programmers • Visual and spatial: pictorial abilities; used by engineers, inventors, artists • Music: musical abilities; used by composers, musicians, music critics
Gardner’s Theory of Eight Multiple Intelligences (cont’d) • Bodily-kinesthetic: physical abilities; used by dancers, athletes, surgeons • Intrapersonal: self-knowledge; used by poets, actors, ministers • Interpersonal: social abilities; used by psychologists, teachers, politicians • Naturalistic: ability to understand natural environment; used by biologists, medicine men, organic farmers
Intelligent Intelligence Testing • Culture-fair test: test designed to minimize importance of skills and knowledge that may be more common in some cultures than in others
IQ and Race • Historically, African Americans scored lower on IQ tests than European Americans • Asian Americans scored higher than European Americans • Attempts to explain in genetic terms have been criticized
IQ and Race (cont’d) • Standard IQ tests do not always allow meaningful comparisons between ethnic, cultural, or racial groups • African Americans are more likely than European Americans to live in impoverished environments • “Race” is a concept that makes no genetic sense; external markers, like skin color, have little to do with underlying genetic differences
Wisdom • Intelligence reflects development as well as potential, nurture as well as nature • People can be intelligent without being wise • Wisdom represents a mixture of convergent thinking, intelligence, and reason, spiced with creativity and originality • People who are wise approach life with openness and tolerance