Thinking Language and Intelligence Power Point Presentation by
Thinking, Language, and Intelligence Power. Point® Presentation by Jim Foley © 2013 Worth Publishers
Module 30: Assessing Intelligence
Topics that may test our intelligence § Binet’s mental age test: Predicting school learning challenges § Terman and the Stanford-Binet IQ test: innate intelligence § Wechsler tests § Aptitude vs. Achievement tests § Standardization and Re-Standardization (Flynn Effect) § Reliability and Validity § Is intelligence stable over the lifespan? § Cross-sectional vs. longitudinal studies § Extremes of Intelligence
Assessing Intelligence Assessment refers to the activity and Why Try to Measure Intelligence? the instruments § to study how (and why) people used to measure differ in ability intelligence. The challenge is to § to match strengths and weaknesses make these to jobs and school programs instruments valid § to help the “survival of the fittest” (measure what they process; trying to select the people are supposed to who have the greatest abilities. measure) and This was the position of eugenicist reliable (yielding the same score if Francis Galton (1822 -1911). administered again, even if administered by someone else).
Predicting School Achievement: Alfred Binet § Problem: in the late 1800 s, a new law in France required universal education even for those without the ability to succeed with the current instruction. § Solution: Alfred Binet devised tests for children to determine which ones needed help. § Binet hoped to predict a child’s level of success in regular education.
Intelligence: Growing with Age? § Alfred Binet assumed that all children follow the same course of development, some going more quickly, and others more slowly. § Binet’s tests attempted to measure mental age--how far the child had come along on the “normal” developmental pathway. § The implication was that children with lower ability were delayed (with a mental age below their chronological age), and not disabled; with help, they could improve.
Binet Stanford-Binet § Lewis Terman, of Stanford University, adapted Alfred Binet’s test, adding new test items and extending the age range into adulthood. § Terman also tested many California residents to develop new norms, that is, new information about how people typically performed on the test. § The result was the Stanford-Binet intelligence test. William Stern’s scoring (1914) of the Stanford-Binet test resulted in the concept of IQ, the Intelligence Quotient. Binet reported scores as simply one’s mental age; a 10 year old with below average intelligence might have a mental age of 8. William Stern preserved Binet’s comparison of mental to chronological age as: ratio/quotient. Q: What IQ score do we get for
What do scores mean? § Lewis Terman, of Stanford University, began with a different assumption than Binet; Terman felt that intelligence was unchanging and innate (genetic). § Later, Terman saw how scores can be affected by people’s level of education and their familiarity with the language and culture used in the test. What to do if you score low on an IQ test? Study, and develop selfdiscipline and attention span. Binet
Aptitude vs. Achievement § Achievement tests measure what you already have learned. Examples include a literacy test, a driver’s license exam, and a final exam in a psychology course. § Aptitude tests attempt to predict your ability to learn new skills. § The SAT, ACT, and GRE are supposed to predict your ability to do well in future academic work. If the SAT is an aptitude test, should it correlate with IQ? IQ SAT scores (verbal + quantitative)
David Wechsler’s Tests: Intelligence PLUS The Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC) measure “g”/IQ and have subscores for: verbal comprehension. processing speed. perceptual organization. working memory.
Principles of Test Construction In order for intelligence or other psychological tests to generate results that are considered useful, the tests (and their scores) must be: standardized. reliable. valid.
Standardization Many intelligence tests generate a raw score based on the number of answers correct, but can we turn this into a number that tells us how smart/capable a person is compared to the general population? Standardization means defining the meaning of scores based on a comparison with the performance of others who have taken the test before. William Stern compared our intelligence test score to others by finding a “mental age” of people who scored on average the way we did. A newer method of generating an intelligence test score is to determine where your raw score falls on a distribution of scores by people of your chronological age.
Standardization: How “Normal” is Your Score? Number of people with this score If we stacked a bunch of Weschler Intelligence Tests (by people your age) in a pile placed by raw score (number of test items correct), there would be a few very high scores and a few low scores, and a big pile in the middle; this bell-shaped pile is called the normal curve. We will call the average raw score “IQ 100. ” Comparing your score to this standard set of scores: if you score higher than 50 percent of people, your IQ is 100. If your score is higher than 98 percent of the population, your IQ is around what number?
Re-Standardization and the Flynn Effect Re-Standardization: Re-testing a sample of the general population to make an updated, accurate comparison group, in case people are smarter than they used to be when the test was first made. The Flynn Effect: Performance on intelligence tests has improved over the years, worldwide.
Test your understanding You took an intelligence test last week and were assigned a number of 120. Then, after decades of the Flynn effect, the test was restandardized this week. Today, you took the same test and got exactly the same number of items correct. Your new intelligence test score is most likely to be: A. 105 B. 120 C. 128
Reliability and Validity A test or other measuring tool is reliable when it generates consistent results. § § Split-half reliability: do two halves of the test yield the same results? Test-retest reliability: will the test give the same result if used again? If your height was measured with a ruler made of stretchy material, what would be the problem? A test or measure has validity if it accurately measures what it is supposed to measure. Content validity: the test correlates well with the relevant criterion, trait, or behavior § Predictive validity: the test predicts future performance (e. g. an aptitude test relates to future grades) If your height was measured with a yardstick on which the units were too small, what would be the problem? §
Predictive Validity: Only in Broad Ranges At the higher range of weights and success, weight is less of a valid predictor of success of football linemen.
Dynamics of Intelligence Are intelligence test scores stable or do they change with age?
Stability of Intelligence during Aging Evidence for change/decline Evidence for stability Cross-sectional studies examine people of different ages all at once. Older adults do not perform as well as younger adults on intelligence tests. § What factors could explain this? § What is different about these different populations other than their chronological age? Longitudinal studies track the performance of one group of people, or cohort, over time. This method yields evidence that intelligence remains stable, or even increases, over time. § What could account for this result? § What are the shortcomings of this method?
Stability of Intelligence during Aging Putting the evidence together Can we combine the information on this chart and form a general impression about whether intelligence declines with age?
Stability of Intelligence during Aging: Which type of intelligence? Based on this chart, at what age might you do best at completing a crossword puzzle quickly?
Fluid and Crystallized Intelligence Fluid intelligence refers to the ability to think quickly and abstractly. Crystallized intelligence refers to accumulated wisdom, knowledge, expertise, and vocabulary.
Stability of Intelligence Test Scores Over the Lifespan Pushing toddlers to learn does not seem to help much. Only by age four is a child’s performance on intelligence tests a predictor of future performance on intelligence tests. Based on the results of a longitudinal study depicted in this chart, does intelligence test score at age 11 predict intelligence test score at age 80?
Intelligence and Longevity In a Scottish longitudinal study, 11 -year-olds with higher intelligence test scores lived longer and more independently and were less likely to develop Alzheimer’s Disease. In a study of nuns , those with lower verbal ability were later more likely to develop Alzheimer’s Disease, which includes a shorter lifespan.
Extremes of Intelligence The Wechsler Intelligence Scale is set so that about 2 percent of the population is above 130 and about 2 percent of the population is below 70. Intellectual Disability Very High Intelligence, Gifted
Extremes of Intelligence “Intellectual disability” refers to people who § have an IQ around 70 or below. § have difficulty with adaptive skills, such as: § conceptual skills (literacy and calculation). § social skills, including making safe social choices. § practical daily living skills such as hygiene, occupational skills, and using transportation. § Although some people with high intelligence test scores can seem socially delayed or withdrawn, most are “successful. ” § “Gifted” children, like any children, learn best with an appropriate level of challenge. § Segregated, “tracked” programs, however, often unfairly widen achievement gaps.
Photo Credits • • • Slide 2: Slide 10: Lew Merrim / Science Source Slide 5 & 8: Bettmann/Corbis Slide 10: Lew Merrim / Science Source Slide 17: © 2003 Peter Menzel/Robosapiens Slide 21: Ann Baldwin/Shutterstock Slide 26: AP Photo/Damian Dovarganes
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