9.3 Intelligence and Its Assessment

So far, we have considered how our species thinks and communicates. But we differ from one another in these abilities. School boards, courts, and scientists debate the use and fairness of tests that assess people’s mental abilities and assign them a score. In psychology, no controversy has been more heated than the question of whether there exists in each person a general intellectual capacity that can be measured and quantified as a number.

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In this section, we consider some findings from a century of research, as psychologists have searched for answers to these questions and more:

What Is Intelligence?

intelligence the mental potential to learn from experience, solve problems, and use knowledge to adapt to new situations.

9-13 How do psychologists define intelligence, and what are the arguments for g?

In many studies, intelligence has been defined as whatever intelligence tests measure, which has tended to be school smarts. But intelligence is not a quality like height or weight, which has the same meaning to everyone worldwide. People assign the term intelligence to the qualities that enable success in their own time and culture (Sternberg & Kaufman, 1998). In Cameroon’s equatorial forest, intelligence may reflect understanding the medicinal qualities of local plants. In a North American high school, it may reflect mastering difficult concepts in tough courses. In both places, intelligence is the mental potential to learn from experience, solve problems, and use knowledge to adapt to new situations.

You probably know some people with talents in science, others who excel in the humanities, and still others gifted in athletics, art, music, or dance. You may also know a talented artist who is stumped by the simplest math problem, or a brilliant math student who struggles when discussing literature. Are all these people intelligent? Could you rate their intelligence on a single scale? Or would you need several different scales? Simply put, is intelligence a single overall ability or several specific abilities?

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Hands-on healing The socially constructed concept of intelligence varies from culture to culture. This natural healer in Cameroon displays intelligence in his knowledge about medicinal plants and his understanding of the needs of the people he is helping.
Heiner Heine/© imagebroker/Alamy

Spearman’s General Intelligence Factor

general intelligence (g) a general intelligence factor that, according to Spearman and others, underlies specific mental abilities and is therefore measured by every task on an intelligence test.

Charles Spearman (1863-1945) believed we have one general intelligence (often shortened to g) that is at the heart of all of our intelligent behavior, from navigating the sea to excelling in school. He granted that people often have special, outstanding abilities. But he noted that those who score high in one area, such as verbal intelligence, typically score higher than average in other areas, such as spatial or reasoning ability.

g is one of the most reliable and valid measures in the behavioral domain . . . and it predicts important social outcomes such as educational and occupational levels far better than any other trait.”

Behavior geneticist Robert Plomin (1999)

Spearman’s belief stemmed in part from his work with factor analysis, a statistical procedure that identifies clusters of related items. In this view, mental abilities are much like physical abilities: The ability to run fast is distinct from the eye-hand coordination required to throw a ball on target. Yet there remains some tendency for good things to come packaged together—for running speed and throwing accuracy to correlate. In both athleticism and intelligence, several distinct abilities tend to cluster together and to correlate enough to define a general underlying factor. Distinct brain networks enable distinct abilities, with g explained by their coordinated activity (Hampshire et al., 2012).

Theories of Multiple Intelligences

9-14 How do Gardner’s and Sternberg’s theories of multiple intelligences differ, and what criticisms have they faced?

Other psychologists, particularly since the mid-1980s, have sought to extend the definition of intelligence beyond the idea of academic smarts.

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Jonathan Larsen/Diadem Images/Alamy

GARDNER’S MULTIPLE INTELLIGENCES Howard Gardner has identified eight relatively independent intelligences, including the verbal and mathematical aptitudes assessed by standardized tests (FIGURE 9.13 below). Thus, the computer programmer, the poet, the street-smart adolescent, and the basketball team’s play-making point guard exhibit different kinds of intelligence (Gardner, 1998). Gardner (1999) has also proposed a ninth possible intelligence—existential intelligence—the ability “to ponder large questions about life, death, existence.”

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Figure 9.13: FIGURE 9.13 Gardner’s eight intelligences Gardner has also proposed a ninth possible intelligence—existential intelligence—the ability to ponder deep questions about life.

savant syndrome a condition in which a person otherwise limited in mental ability has an exceptional specific skill, such as in computation or drawing.

Gardner (1983, 2006, 2011; Davis et al., 2011) views these intelligence domains as multiple abilities that come in different packages. Brain damage, for example, may destroy one ability but leave others intact. And consider people with savant syndrome. Despite their island of brilliance, these people often score low on intelligence tests and may have limited or no language ability (Treffert & Wallace, 2002). Some can compute complicated calculations quickly and accurately, or identify almost instantly the day of the week corresponding to any historical date, or render incredible works of art or musical performance (Miller, 1999).

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Islands of genius: Savant syndrome After a brief helicopter ride over Singapore followed by five days of drawing, British savant artist Stephen Wiltshire accurately reproduced an aerial view of the city from memory.
Then Chih Wey/Xinhua/ZUMA Wire/Newscom

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About four in five people with savant syndrome are males. Many also have autism spectrum disorder (ASD), a developmental disorder. The late memory whiz Kim Peek (who did not have ASD) inspired the movie Rain Man. In 8 to 10 seconds, he could read and remember a page. During his lifetime, he memorized 9000 books, including Shakespeare’s works and the Bible. He could provide GPS-like travel directions within any major U.S. city. Yet he could not button his clothes, and he had little capacity for abstract concepts. Asked by his father at a restaurant to lower his voice, he slid down in his chair to lower his voice box. Asked for Lincoln’s Gettysburg Address, he responded, “227 North West Front Street. But he only stayed there one night—he gave the speech the next day” (Treffert & Christensen, 2005).

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The New Yorker Collection, 1988, Donald Reilly from cartoonbank.com

“You have to be careful, if you’re good at something, to make sure you don’t think you’re good at other things that you aren’t necessarily so good at. . . . Because I’ve been very successful at [software development] people come in and expect that I have wisdom about topics that I don’t.”

Philanthropist Bill Gates (1998)

STERNBERG’S THREE INTELLIGENCES Robert Sternberg (1985, 2011) agrees with Gardner that there is more to success than traditional intelligence and that we have multiple intelligences. But his triarchic theory proposes three, not eight or nine, intelligences:

Gardner and Sternberg differ in some areas, but they agree on two important points: Multiple abilities can contribute to life success, and varieties of giftedness bring spice to life and challenges for education. As a result of this research, many teachers have been trained to appreciate such variety and to apply multiple intelligence theories in their classrooms.

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Street smarts This child selling candy on the streets of Manaus, Brazil, is developing practical intelligence at a very young age.
David R. Frazier Photolibrary, Inc./Alamy

CRITICISMS OF MULTIPLE INTELLIGENCE THEORIES Wouldn’t it be wonderful if the world were so just that a weakness in one area would be compensated by genius in another? Alas, say critics, the world is not just (Ferguson, 2009; Scarr, 1989). Research using factor analysis has confirmed that there is a general intelligence factor (Johnson et al., 2008): g matters. It predicts performance on various complex tasks and in various jobs (Gottfredson, 2002a,b, 2003a,b; see also FIGURE 9.14). Much as jumping ability is not a predictor of jumping performance when the bar is set a foot off the ground—but becomes a predictor when the bar is set higher—so extremely high cognitive ability scores predict exceptional attainments, such as doctoral degrees and publications (Kuncel & Hezlett, 2010).

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Figure 9.14: FIGURE 9.14 Smart and rich? Jay Zagorsky (2007) tracked 7403 participants in the U.S. National Longitudinal Survey of Youth across 25 years. As shown in this scatterplot, their intelligence scores correlated +.30, a moderate positive correlation, with their later income. Each dot indicates a given youth’s intelligence score and later adult income.
Reprinted from Intelligence Vol 35 Zagorsky, J. L., Do you have to be smart and rich? The impact of I.Q. wealth, income and financial distress, 489-501 (2007) with permission from Elsevier.

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Spatial intelligence genius In 1998, World Checkers Champion Ron “Suki” King of Barbados set a new record by simultaneously playing 385 players in 3 hours and 44 minutes. Thus, while his opponents often had hours to plot their game moves, King could only devote about 35 seconds to each game. Yet he still managed to win all 385 games!
Courtesy of Cameras on Wheels

Even so, “success” is not a one-ingredient recipe. High intelligence may help you get into a profession (via the schools and training programs that take you there), but it won’t make you successful once there. Success is a combination of talent and grit: Those who become highly successful tend also to be conscientious, well connected, and doggedly energetic. Researchers report a 10-year rule: A common ingredient of expert performance in chess, dancing, sports, computer programming, music, and medicine is “about 10 years of intense, daily practice” (Ericsson, 2002, 2007; Simon & Chase, 1973). Becoming a professional musician, for example, requires native ability. But it also requires practice—about 11,000 hours on average, and a minimum of 3000 hours (Campitelli & Gobet, 2011). The recipe for success is a gift of nature plus a whole lot of nurture.

Bees, birds, chimpanzees, and other species also require time and experience to acquire peak expertise in skills such as foraging (Helton, 2008). As with humans, performance tends to peak near midlife.

For more on how self-disciplined grit feeds achievement, see Chapter 10.

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XC/DmT7op2h0Q2IoigAebTC8F19Ac3f21FJS6wjeHTtfZkRDhR6iJtb7MSMl+AEjYkzxtSVcZLTn4Rqxtb4Zk+PRH/UOdn9q1QvLyXCf8vxVw0cWWKpcOLIsto9YqdS2gP/5aG/dfB5dYedIfi15Kx0yYVRFIX2iNlbSmSujORIi8cI66oR2z6jYB2k=
ANSWER: People with savant syndrome have limited mental ability overall but possess one or more exceptional skills. According to Howard Gardner, this suggests that our abilities come in separate packages rather than being fully expressed by one general intelligence that encompasses all of our talents.

Emotional Intelligence

9-15 What are the four components of emotional intelligence?

Is being in tune with yourself and others also a sign of intelligence, distinct from academic intelligence? Some researchers say Yes. They define social intelligence as the know-how involved in social situations and managing yourself successfully (Cantor & Kihlstrom, 1987). People with high social intelligence can read social situations the way a skilled soccer player reads the defense or a meteorologist reads the weather. The concept was first proposed in 1920 by psychologist Edward Thorndike, who noted, “The best mechanic in a factory may fail as a foreman for lack of social intelligence” (Goleman, 2006, p. 83).

emotional intelligence the ability to perceive, understand, manage, and use emotions.

One line of research has explored a specific aspect of social intelligence called emotional intelligence, consisting of four abilities (Mayer et al., 2002, 2011, 2012):

Emotionally intelligent people are both socially aware and self-aware. Those who score high on managing emotions enjoy higher-quality interactions with friends (Lopes et al., 2004). They avoid being hijacked by overwhelming depression, anxiety, or anger. They can read others’ emotional cues and know what to say to soothe a grieving friend, encourage a workmate, and manage a conflict. They can delay gratification in pursuit of long-range rewards, rather than being overtaken by immediate impulses. They often succeed in career, marriage, and parenting situations where academically smarter (but emotionally less intelligent) people might fail (Cherniss, 2001a,b; Ciarrochi et al., 2006). Emotionally intelligent people also perform modestly better on the job (O’Boyle et al., 2011).

Some scholars, however, are concerned that emotional intelligence stretches the intelligence concept too far (Visser et al., 2006). Howard Gardner (1999) includes interpersonal and intrapersonal intelligences as two of his multiple intelligences. But let us instead, he offers, respect emotional sensitivity, creativity, and motivation as important but different. Stretch intelligence to include everything we prize and the word will lose its meaning.

The procrastinator’s motto: “Hard work pays off later; laziness pays off now.”

* * *

For a summary of these theories of intelligence, see TABLE 9.2.

Table 9.2: TABLE 9.2
Comparing Theories of Intelligence
Theory Summary Strengths Other Considerations
Spearman’s general intelligence (g) A basic intelligence predicts our abilities in varied academic areas. Different abilities, such as verbal and spatial, do have some tendency to correlate. Human abilities are too diverse to be encapsulated by a single general intelligence factor.
Gardner’s multiple intelligences Our abilities are best classified into eight or nine independent intelligences, which include a broad range of skills beyond traditional school smarts. Intelligence is more than just verbal and mathematical skills. Other abilities are equally important to our human adaptability. Should all of our abilities be considered intelligences? Shouldn’t some be called less vital talents?
Sternberg’s triarchic theory Our intelligence is best classified into three areas that predict real-world success: analytical, creative, and practical. These three domains can be reliably measured.

1. These three domains may be less independent than Sternberg thought and may actually share an underlying g factor.

2. Additional testing is needed to determine whether these domains can reliably predict success.

Emotional intelligence Social intelligence is an important indicator of life success. Emotional intelligence is a key aspect, consisting of perceiving, understanding, managing, and using emotions. The four components that predict social success. Does this stretch the concept of intelligence too far?

Assessing Intelligence

9-16 What is an intelligence test, and what is the difference between achievement and aptitude tests?

intelligence test a method for assessing an individual’s mental aptitudes and comparing them with those of others, using numerical scores.

An intelligence test assesses people’s mental abilities and compares them with others, using numerical scores. Psychologists classify such tests as either aptitude tests, intended to predict your ability to learn a new skill, or achievement tests, intended to reflect what you have already learned. How do we design such tests, and what makes them credible? Consider why psychologists created tests of mental abilities and how they have used them.

aptitude test a test designed to predict a person’s future performance; aptitude is the capacity to learn.

achievement test a test designed to assess what a person has learned.

What Do Intelligence Tests Test?

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9-17 When and why were intelligence tests created, and how do today’s tests differ from early intelligence tests?

Barely a century ago, psychologists began designing tests to assess people’s abilities. Some measured aptitude (ability to learn). Others assessed achievement (what people have already learned).

ALFRED BINET: PREDICTING SCHOOL ACHIEVEMENT Modern intelligence testing traces its birth to early-twentieth-century France, where a new law required all children to attend school. French officials knew that some children, including many newcomers to Paris, would struggle and need special classes. But how could the schools make fair judgments about children’s learning potential? Teachers might assess children who had little prior education as slow learners. Or they might sort children into classes on the basis of their social backgrounds. To minimize such bias, France’s minister of public education gave Alfred Binet (1857-1911) the task of solving this problem.

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Alfred Binet (1857–1911) “Some recent philosophers have given their moral approval to the deplorable verdict that an individual’s intelligence is a fixed quantity, one which cannot be augmented. We must protest and act against this brutal pessimism” (Binet, 1909, p. 141).

mental age a measure of intelligence test performance devised by Binet; the chronological age that most typically corresponds to a given level of performance. Thus, a child who does as well as an average 8-year-old is said to have a mental age of 8.

In 1905, Binet and his student, Théodore Simon, first presented their work under the archaic title, “New Methods for Diagnosing the Idiot, the Imbecile, and the Moron” (Nicolas & Levine, 2012). They began by assuming that all children follow the same course of intellectual development, but that some develop more rapidly. A “dull” child should score much like a typical younger child, and a “bright” child like a typical older child. Binet and Simon now had a clear goal: They would measure each child’s mental age, the level of performance typically associated with a certain chronological age. The average 8-year-old, for example, has a mental age of 8. An 8-year-old with a below-average mental age (perhaps performing at the level of a typical 6-year-old) would struggle with schoolwork considered normal for 8-year-olds.

“The IQ test was invented to predict academic performance, nothing else. If we wanted something that would predict life success, we’d have to invent another test completely.”

Social psychologist Robert Zajonc (1984b)

Binet and Simon tested a variety of reasoning and problem-solving questions on Binet’s two daughters, and then on “bright” and “backward” Parisian schoolchildren. Items that the successful students more often answered correctly could then be used to predict how well other French children would handle their schoolwork. Binet hoped his test would be used to improve children’s education, but he also feared it would be used to label children and limit their opportunities (Gould, 1981).

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I/1tcYqQGz6qgDi7QxRE7EhPbrhW3VCC3u3m7ImGockjuZS+J25x5pc4yNHWzyh85jO5sTQodEsWBdwe0+Zn4/00jfP3FvFQVAf1Ff81s17inLYZoXjXtbKETgkCfaZwDuXwjmFnGuIjPhQt+DzQrwBsyZtTyMqh0j+JJw==
ANSWER: Binet hoped that determining mental age (the age that typically corresponds to a child's level of performance) would help identify appropriate school placements for children.

Stanford-Binet the widely used American revision (by Terman at Stanford University) of Binet’s original intelligence test.

LEWIS TERMAN: THE INNATE IQ Binet’s fears were realized soon after his death in 1911, when others adapted his tests for use as a numerical measure of inherited intelligence. Stanford University professor Lewis Terman (1877-1956) found that the Paris-developed questions and age norms worked poorly with California schoolchildren. He adapted some items, added others, and established new standards for various ages. He also extended the upper end of the test’s range from teenagers to “superior adults” and gave his revision the name it retains today—the Stanford-Binet. Terman assumed that certain ethnic groups were naturally more intelligent, and he supported the controversial eugenics movement, which aimed to protect and improve human genetic quality through selective sterilization and breeding.

intelligence quotient (IQ) defined originally as the ratio of mental age (ma) to chronological age (ca) multiplied by 100 (thus, IQ = ma/ca × 100). On contemporary intelligence tests, the average performance for a given age is assigned a score of 100.

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Dave Coverly/Speed Bump

From such tests, German psychologist William Stern derived the famous intelligence quotient, or IQ. The IQ was simply a person’s mental age divided by chronological age and multiplied by 100 to get rid of the decimal point. Thus, an average child, whose mental age (8) and chronological age (8) are the same, has an IQ of 100. But an 8-year-old who answers questions at the level of a typical 10-year-old has an IQ of 125:

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The original IQ formula worked fairly well for children but not for adults. (Should a 40-year-old who does as well on the test as an average 20-year-old be assigned an IQ of only 50?) Most current intelligence tests, including the Stanford-Binet, no longer compute an IQ in this manner (though the term IQ still lingers in everyday vocabulary as shorthand for “intelligence test score”). Instead, they represent the test-taker’s performance relative to the average performance of others the same age. This average performance is arbitrarily assigned a score of 100, and about two-thirds of all test-takers fall between 85 and 115.

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ORRSiCKp0gsPdzArdD4H5Hqyhcw5LcwZA7BJVb4MX+ak7tKM1WRJDYtCrhov6OlMsY3lAUHYKaIWbrkKpyeqZhtLqjCesTFuyGpUEl2agnOc6fk3zKkroNmvTNPTeo/PuJVrXBT7twTfcixVkZ0YI2kOXQakUybs3ZXcv+MG/AJEvMxQLdI+BLazgr8XtGaKrqK6d+msHjMI/onXQScKifa2Xz9fdv6R82ERLsNJ6ee0VxwM2FG0f49WtVX9TFVQDyVwug==
ANSWER: 125 (5 ÷ 4 x 100 = 125)

Wechsler Adult Intelligence Scale (WAIS) the WAIS and its companion versions for children are the most widely used intelligence tests; contain verbal and performance (nonverbal) subtests.

DAVID WECHSLER: SEPARATE SCORES FOR SEPARATE SKILLS Psychologist David Wechsler created what is now the most widely used individual intelligence test, the Wechsler Adult Intelligence Scale (WAIS). There is a version for school-age children (the Wechsler Intelligence Scale for Children [WISC]), and another for preschool children (Evers et al., 2012). The WAIS (2008) edition consists of 15 subtests, including:

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Matching patterns Block design puzzles test visual abstract processing ability. Wechsler’s individually administered intelligence test comes in forms suited for adults and children.
© Richard T. Nowitz/Corbis

The WAIS yields both an overall intelligence score and individual scores for verbal comprehension, perceptual organization, working memory, and processing speed. Striking differences among these individual scores can provide clues to cognitive strengths or weaknesses. For example, a low verbal comprehension score combined with high scores on other subtests could indicate a reading or language disability. Other comparisons can help a therapist establish a rehabilitation plan for a stroke patient. In such ways, these tests help realize Binet’s aim: to identify opportunities for improvement and strengths that teachers and others can build upon.

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An employer with a pool of applicants for a single available position is interested in testing each applicant's potential. To help her decide whom she should hire, she should use an qbbveL6N5hOq3Qe8u2zfYA== (achievement/aptitude) test. That same employer wishing to test the effectiveness of a new, on-the-job training program would be wise to use an by/Tq8cs5jEJhga1bx+RCg== (achievement/aptitude) test.

Three Tests of a “Good” Test

9-18 What is a normal curve, and what does it mean to say that a test has been standardized and is reliable and valid?

To be widely accepted, a psychological test must be standardized, reliable, and valid. The Stanford-Binet and Wechsler tests meet these requirements.

standardization defining uniform testing procedures and meaningful scores by comparison with the performance of a pretested group.

normal curve the bell-shaped curve that describes the distribution of many physical and psychological attributes. Most scores fall near the average, and fewer and fewer scores lie near the extremes.

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WAS THE TEST STANDARDIZED? The number of questions you answer correctly on an intelligence test would reveal almost nothing. To know how well you performed, you would need some basis for comparison. That’s why test-makers give new tests to a representative sample of people. The scores from this pretested group become the basis for future comparisons. If you later take the test following the same procedures, your score will be meaningful when compared with others. This process is called standardization.

If we construct a graph of test-takers’ scores, the scores typically form a bell-shaped pattern called the normal curve. No matter what attributes we measure—height, weight, or mental aptitude—people’s scores tend to form a bell curve. The highest point is the midpoint, or the average score. On an intelligence test, we give this average score a value of 100 (FIGURE 9.15). Moving out from the average, toward either extreme, we find fewer and fewer people. For the Stanford-Binet and Wechsler tests, a person’s score indicates whether that person’s performance fell above or below the average. A performance higher than all but 2 percent of all scores earns an intelligence score of 130. A performance lower than 98 percent of all scores earns an intelligence score of 70.

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Figure 9.15: FIGURE 9.15 The normal curve Scores on aptitude tests tend to form a normal, or bell-shaped, curve around an average score. For the Wechsler scale, for example, the average score is 100

reliability the extent to which a test yields consistent results, as assessed by the consistency of scores on two halves of the test, on alternative forms of the test, or on retesting.

IS THE TEST RELIABLE? Knowing your score in comparison to the standardization group still won’t tell you much unless the test has reliability. A reliable test gives consistent scores, no matter who takes the test or when they take it. To check a test’s reliability, researchers test people many times. They may retest people using the same test, or they may split the test in half and see whether odd-question scores and even-question scores agree. If the two sets of scores generally agree, or correlate, the test is reliable. The higher the correlation, the higher the test’s reliability. The tests we have considered so far—the Stanford-Binet, the WAIS, and the WISC—are, after early childhood, very reliable (about +.9). When retested, people’s scores generally match their first score closely.

validity the extent to which a test measures or predicts what it is supposed to. (See also content validity and predictive validity.)

image See LaunchPad’s Video: Correlational Studies below for a helpful tutorial animation.

IS THE TEST VALID? High reliability does not ensure a test’s validity—the extent to which the test actually measures or predicts what it promises. Imagine using a miscalibrated tape measure to measure people’s heights. Your results would be very reliable. No matter how many times you measured, people’s heights would be the same. But your results would not be valid, because you would not be giving the information you promised: real height.

content validity the extent to which a test samples the behavior that is of interest.

predictive validity the success with which a test predicts the behavior it is designed to predict; it is assessed by computing the correlation between test scores and the criterion behavior. (Also called criterion-related validity.)

Tests that tap the pertinent behavior, or criterion, have content validity. The road test for a driver’s license has content validity because it samples the tasks a driver routinely faces. Course exams have content validity if they assess your mastery of course material. But we expect intelligence tests to have predictive validity: They should predict future performance, and to some extent they do.

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The predictive power of aptitude tests is fairly strong in the early school years, but later it weakens. Past grades, which reflect both aptitude and motivation, are better predictors of future achievements.

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x/FD9EHtA35umFS5sioNrKp/qJvUDbCy7fmw+6j9qSvHV3EAP361xZ2VWVQCnJObw7sjtOGQdg18uvZNLDPFxNxyRvUvHBln/h8uSsC9Y2WtttL9dCtU0XhCv3QXNRF8/mdcl/2qY2ImVF7ZdumhlvoI+yOdJoJMImjK2VsWXPUPESJwRyRSpuCq3vWOOiemwZP8Z8aYbfk=
ANSWER: A psychological test must be standardized (pretested on a representative sample of people), reliable (yielding consistent results), and valid (measuring what it is supposed to measure).

Question

Correlation coefficients were used in this section. Here's a quick review: Correlations do not indicate cause-effect, but they do tell us whether two things are associated in some way. A correlation of –1.0 represents perfect EbHNyHmscWGO4Jw2eFSSBFnScuo= (agreement/disagreement) between two sets of scores: As one score goes up, the other score goes YTmAi4hUOd6IM9X0 (up/down). A correlation of OMdCFrWNbBz3PEdX represents no association. The highest correlation, +1.0, represents perfect XEGh4tWohdwySfFde9oWOg== (agreement/disagreement): As the first score goes up, the other score goes SVrMQKz4p+A= (up/down).

The Dynamics of Intelligence

Aging and Intelligence

9-19 How does aging affect crystallized and fluid intelligence?

Does intelligence increase, decrease, or remain constant as we age? The answer depends on the type of intellectual performance we measure:

crystallized intelligence our accumulated knowledge and verbal skills; tends to increase with age.

fluid intelligence our ability to reason speedily and abstractly; tends to decrease with age, especially during late adulthood.

How do we know? Developmental psychologists use longitudinal studies (restudying the same group at different times across their life span) and cross-sectional studies (comparing members of different age groups at the same time) to study the way intelligence and other traits change with age. (See Appendix A for more information.) With age we lose and we win. We lose recall memory and processing speed, but we gain vocabulary and knowledge (FIGURE 9.16 below). Fluid intelligence may decline, but older adults’ social reasoning skills increase, as shown by an ability to take multiple perspectives, to appreciate knowledge limits, and to offer helpful wisdom in times of social conflict (Grossman et al., 2010). Decisions also become less distorted by negative emotions such as anxiety, depression, and anger (Blanchard-Fields, 2007; Carstensen & Mikels, 2005).

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Figure 9.16: FIGURE 9.16 With age, we lose and we win. Studies reveal that word power grows with age, while fluid intelligence dimensions decline. (Data from Salthouse, 2010.)
Ann Baldwin/Shutterstock

image See LaunchPad’s Video: Longitudinal and Cross-Sectional Studies for a helpful tutorial animation.

“Knowledge is knowing a tomato is a fruit; wisdom is not putting it in a fruit salad.”

Anonymous

Age-related cognitive differences help explain why older adults are less likely to embrace new technologies (Charness & Boot, 2009; Lenhart, 2015). These cognitive differences also help explain why mathematicians and scientists produce much of their most creative work during their late twenties or early thirties, when fluid intelligence is at its peak (Jones et al., 2014). In contrast, authors, historians, and philosophers tend to produce their best work in their forties, fifties, and beyond—after accumulating more knowledge (Simonton, 1988, 1990). Poets, for example, who depend on fluid intelligence, reach their peak output earlier than prose authors, who need the deeper knowledge reservoir that accumulates with age. This finding holds in every major literary tradition, for both living and dead languages.

“In youth we learn, in age we understand.”

Marie Von Ebner-Eschenbach, Aphorisms, 1883

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YUx/rNK7MAts9OL8Yxp5Cj2z7kPq0ZfWxU+b8dLs9hMR8WZSXwSxS8mDyrs0Aj8cY7Ns8uGmGxuQzKXrTQ3vclv8MTBJFfrPk5gZs8SiZrHBpZLHXvp7LMpLTop3w69pFpf7vuHspZZBitzHpEkQckeZkbVX7vFIdGmJDPAPORg4dStWYDxCY0399RAnikDk7EKRMR9Ap0EbbZm5RcwlcLWgQh15Loja1sODKRw1fqR6pkA9SNKeuM/YCEuqC7tD3ravvi+R12WtHnbsFFu01Vb3LV9hzQtCJsehODK90ku9b9rwvQ2nWUdX+57gSSTQzgHlNH4ca6SwX9G9TRtfXpadqEcidHWD4N5OgxXF+EOqG6ojoaTdqzwaWaXNY95X5STH/KkSBpN4NNU/XE3/y8t5mwBQPD+MJE/pKjYRnvRnDUYXq9shwsX1gm0DyvaeDcINhmthN2bL/K1HTRlyEZAAELF8RaVC4uPZuCsWo2H7RVlTfNcpPw==
ANSWER: Researcher A should develop a longitudinal study to examine how intelligence changes in the same people over the life span. Researcher B should develop a cross-sectional study to examine the intelligence of people now at various life stages.

Stability Over the Life Span

9-20 How stable are intelligence test scores over the life span?

What about the stability of early-life intelligence scores? For most children, casual observation and intelligence tests before age 3 only modestly predict their future aptitudes (Humphreys & Davey, 1988; Tasbihsazan et al., 2003). Even Albert Einstein was once thought “slow”—as he was in learning to talk (Quasha, 1980).

By age 4, however, children’s performance on intelligence tests begins to predict their adolescent and adult scores. The consistency of scores over time increases with the age of the child. By age 11, the stability becomes impressive, as Ian Deary and his colleagues (2004, 2009, 2013) discovered. Their amazing longitudinal studies have been enabled by their country, Scotland, which did something that no nation has done before or since. On June 1, 1932, essentially every child in the country born in 1921—87,498 children around age 11—took an intelligence test. The aim was to identify working-class children who would benefit from further education. Sixty-five years later to the day, Patricia Whalley, the wife of Deary’s co-worker, Lawrence Whalley, discovered the test results on dusty storeroom shelves at the Scottish Council for Research in Education, not far from Deary’s Edinburgh University office. “This will change our lives,” Deary replied when Whalley told him the news.

And so it has, with dozens of studies of the stability and the predictive capacity of these early test results. For example, when the intelligence test administered to 11-year-old Scots in 1932 was readministered to 542 survivors as turn-of-the-millennium 80-year-olds, the correlation between the two sets of scores—after nearly 70 years of varied life experiences—was striking (FIGURE 9.17). Ditto when 106 survivors were retested at age 90 (Deary et al., 2013). Another study that followed Scots born in 1936 from ages 11 to 70 confirmed the remarkable stability of intelligence, independent of life circumstance (Johnson et al., 2010).

“Whether you live to collect your old-age pension depends in part on your IQ at age 11.”

Ian Deary, “Intelligence, Health, and Death,” 2005

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Figure 9.17: FIGURE 9.17 Intelligence endures When Ian Deary and his colleagues (2004) retested 80-year-old Scots, using an intelligence test they had taken as 11-year-olds, their scores across seven decades correlated +.66, as shown here. (Data from Deary et al., 2004.) When 106 survivors were again retested at age 90, the correlation with their age 11 scores was +.54 (Deary et al., 2013).

Children and adults who are more intelligent also tend to live healthier and longer lives. Why might this be the case? Deary (2008) proposes four possible explanations:

  1. Intelligence facilitates more education, better jobs, and a healthier environment.

  2. Intelligence encourages healthy living: less smoking, better diet, more exercise.

  3. Prenatal events or early childhood illnesses might have influenced both intelligence and health.

  4. A “well-wired body,” as evidenced by fast reaction speeds, perhaps fosters both intelligence and longevity.

image image IMMERSIVE LEARNING Explore how researchers have studied these issues with LaunchPad’s How Would You Know If Intelligence Changes With Age?

Extremes of Intelligence

9-21 What are the traits of those at the low and high intelligence extremes?

One way to glimpse the validity and significance of any test is to compare people who score at the two extremes of the normal curve. The two groups should differ noticeably, and with intelligence testing, they do.

intellectual disability a condition of limited mental ability, indicated by an intelligence test score of 70 or below and difficulty adapting to the demands of life. (Formerly referred to as mental retardation.)

THE LOW EXTREME At one extreme of the intelligence test normal curve are those with unusually low scores. The American Association on Intellectual and Developmental Disabilities guidelines list two criteria for a diagnosis of intellectual disability (formerly referred to as mental retardation):

  1. A test score indicating performance below 98 percent of test-takers (Schalock et al., 2010). For an intelligence test with a midpoint of 100, that is a score of approximately 70 or below.

  2. Difficulty adapting to the normal demands of independent living, as expressed in three areas:

    • conceptual skills (such as language, literacy, and concepts of money, time, and number).

    • social skills (such as interpersonal skills, social responsibility, following basic rules and laws, and avoiding being victimized).

    • practical skills (such as daily personal care, occupational skill, travel, and health care).

Down syndrome a condition of mild to severe intellectual disability and associated physical disorders caused by an extra copy of chromosome 21.

Intellectual disability is a developmental condition that is apparent before age 18, sometimes with a known physical cause. Down syndrome, for example, is a disorder of varying intellectual and physical severity caused by an extra copy of chromosome 21.

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People diagnosed with a mild intellectual disability—those just below the 70 score—might be better able to live independently today than many decades ago, when they were institutionalized. The tests have been periodically restandardized. As that happened, individuals who scored near 70 on earlier tests have suddenly lost about 6 test-score points. Two people with the same ability level could thus be classified differently, depending on when they were tested (Kanaya et al., 2003; Reynolds et al., 2010). As the intellectual-disability boundary has shifted, more people have become eligible for special education and for Social Security payments. And in the United States (one of only a few industrialized countries with the death penalty), fewer people are now eligible for execution: The U.S. Supreme Court ruled in 2002 that the execution of people with an intellectual disability is “cruel and unusual punishment.” For people near that cutoff score of 70, intelligence testing can be a high-stakes competition. And so it was for Teresa Lewis, a “dependent personality” with limited intellect, who was executed by the state of Virginia in 2010. Lewis, whose reported test score was 72, allegedly agreed to a plot in which two men killed her husband and stepson in exchange for a split of a life insurance payout (Eckholm, 2010). If only she had scored 69.

RETRIEVE IT

Question

JkRjaj4j2wguXgAKJl/4AFVPjJDg2ipPnTZ97hWKGXo+jyRzMM75OQTZH0MIqLK4xvtuVvEBvcGl/bd06ieZMfF1+BsKN6iQZi2dkWvbnC8UepawKnt+KWu/Ijgn+8UN29F+iC/7knwaw8TMoO1I4+qba2ZlGPUmvBo3sPzBXPTXbDMqxB7V2ZlFX3/zy6tYsJx75aR5LvFevxFbCwkTfw==
ANSWER: IQ score is only one measure of a person's ability to function. Other important factors to consider in an overall assessment include conceptual skills, social skills, and practical skills.
image
The extremes of intelligence Moshe Kai Cavalin completed his third college degree at age 14, graduating with a UCLA math degree. According to his mother, he started reading at age 2.
Joe Klamar/AFP/Getty Images

THE HIGH EXTREME In one famous project begun in 1921, Lewis Terman studied more than 1500 California schoolchildren with IQ scores over 135. Terman’s high-scoring children (the “Termites”) were healthy, well adjusted, and unusually successful academically (Friedman & Martin, 2012; Koenen et al., 2009; Lubinski, 2009a). When restudied over the next seven decades, most had attained high levels of education (Austin et al., 2002; Holahan & Sears, 1995). Many were doctors, lawyers, professors, scientists, and writers, though no Nobel Prize winners. (The two future physics Nobel laureates Terman tested failed to score above his gifted-sample cutoff [Hulbert, 2005].)

Recent studies have followed the lives of precocious youths who had aced the math SAT at age 13—by scoring in the top quarter of 1 percent of their age group. By their fifties, these 1650 math whizzes had secured 681 patents (Lubinski et al., 2014). Compared with the math aces, 13-year-olds scoring high on verbal aptitude were, by age 38, more likely to have become humanities professors or written a novel (Kell et al., 2013). About 1 percent of Americans earn doctorates. But among those scoring in the top 1 in 10,000 on the SAT at age 12 or 13, 63 percent had done so.

One of psychology’s whiz kids was Jean Piaget, who by age 15 was publishing scientific articles on mollusks and who went on to become the twentieth century’s most famous developmental psychologist (Hunt, 1993). Children with extraordinary academic gifts are sometimes more isolated, shy, and in their own worlds (Winner, 2000). But most thrive.

REVIEW Intelligence and Its Assessment

Learning Objectives

Test Yourself by taking a moment to answer each of these Learning Objective Questions (repeated here from within the chapter). Research suggests that trying to answer these questions on your own will improve your long-term memory of the concepts (McDaniel et al., 2009).

Question

I7cPued+UQuU70nmYMq9KJYLa++nunH+Z5EApQV7LcmUZeE2pbjUf94hMkgMOvDmvhseL1hywK1DOa8GnwSw9M8gVNaz6ux9Sp/cfeiOgrc6vipuJnvREzoShNogOlAC+XL48mOhuiCnWxCu01VdSxOcEgfnFThPxmSchEpfC1LMwmHPTYIwoHVO3eMOCsphiBtb/o+QlsolP4QoNcRaQcVzQ7dSFIRcIi+yhqaDV6uqGfb33LQM8WCi4oIeH2ysDpLAyht7RebixMxjXX/pIg==
ANSWER: Intelligence is a mental quality consisting of the potential to learn from experience, solve problems, and use knowledge to adapt to new situations. Charles Spearman proposed that we have one general intelligence (g) underlying all other specific mental abilities. He helped develop factor analysis, a statistical procedure that identifies clusters of related abilities.

Question

mojX76afsmilJM4J9+0sHGKIVKhhy5bqaOQijL1xUIodlB/oK5FsQOFYWhX+ILNGCzyCgM2Z8fJV8sMkle3hBPil7dLj9ZvtJ5ehZCSy6IiqE2Aiy33DmzHCXhj5cvvajNO62CzhD8opC97gps4z98a6nTgY0IiB42NZ9fvSw4WnucqbhEZpRF0v70pXuuBlaO0S/8AC+6b163AcyEwwylMFQIUe+Jh+0ETyzp5sGotSEAcUxaiMrLHsT7fxYK80NDNbJPk3GYU5l0FbmZs/cx9C8NlR0RkW7R4Ix/wSX6kfHzxS
ANSWER: Savant syndrome seems to support Howard Gardner's view that we have multiple intelligences. He proposed eight independent intelligences: linguistic, logical-mathematical, musical, spatial, bodily-kinesthetic, intrapersonal, interpersonal, and naturalist. (He has also proposed a ninth possible intelligence—existential intelligence—the ability to ponder deep questions about life.) Robert Sternberg's triarchic theory proposes three intelligence areas that predict real-world skills: analytical (academic problem solving), creative, and practical. Critics note research that has confirmed a general intelligence factor. But highly successful people also tend to be conscientious, well-connected, and doggedly energetic.

Question

W2wBcXkO83qvaTuLK6HlM0a4ynXUg9X/yasPdWKQnT7/95O4aGv3CzlK+N8f2RTYiPoZWV9k5C3pXdw2x5RNCxHtWys9OpZX/JFEGv/0bgXDern8dAfqlle6zqpuUVoHw+nINhtHHSXKRTqvlomhW2Vc/YYJ/4Z8VQ7Hh/T2R/yNJPX6FkE/4jAWXvugkhDPkA8xiqcAgpCkO45Degmxc6Uhomfa1D8Q0pOFKA==
ANSWER: Emotional intelligence, which is an aspect of social intelligence, is the ability to perceive, understand, manage, and use emotions. Emotionally intelligent people achieve greater personal and professional success. Some critics question whether calling these abilities “intelligence” stretches that concept too far.

353

Question

xUVbMFgPFuTBN8fDmP9B3I0f0oDeI0UCXdL2r8LLfYNxYWmZm+Xzyc52u1orH9pnMqwyxCgtRQ3xOKmAoCGu2Q3gHxV8Xz1a3DvffSSw0OoK0OJAxWf/OA/7VCulJl6c7JZvF0QXwAp0lG8HyYWelzjow+Y3fWMYAKz30GUmeGqHaupkn9PJx/WPZu5tbpPh3SrdC5s6ijC2pfRd+RDurQB+Lx4vE6YcXgvY90y9M2AQhGjcx488GSvl82uUq8TcR/fG5O17rRPzJHedaLY1UDPdUC8=
ANSWER: An intelligence test is a method for assessing an individual's mental aptitudes and comparing them with others, using numerical scores. Aptitude tests measure the ability to learn, while achievement tests measure what we have already learned.

Question

jN3IiG7bFbZkojG+fERXesavG+RDSUlDscvR0WorMGIWKz4wu+VKurp2wj7jybAJSDF30GlcMS2vvvOHfSTOeQMJut1bnARxPCrWeB0yiaeD2BfDLVSpz9+T6GcciJIzM1wfc6eNu689ajrQ0YkMQ2K1eXndyxwMqvPDv6DPThusQcwLS+YkBYJSj4fyPUb+KWWXVPQIVQCfGdBdQ92Wk2XRCKbEat1NTlTTqXqeKLTsHq2AekeI/LmrAJ85ZTOo1hnB3VWVRMgtz4OrOHaxs87O4zZ2Dc1+pLeqbXCSE6s=
ANSWER: Alfred Binet started the modern intelligence-testing movement in France in 1904 when he developed questions to help predict children's future progress in the Paris school system. During the early twentieth century, Lewis Terman of Stanford University revised Binet's work for use in the United States. He believed intelligence was inherited, and he thought his Stanford-Binet could help guide people toward appropriate opportunities. Terman's assumption that certain ethnic groups were naturally more intelligent realized Binet's fear that intelligence tests would be used to label children and limit their opportunities. William Stern contributed the concept of the IQ (intelligence quotient). The most widely used intelligence tests today are the Wechsler Adult Intelligence Scale (WAIS) and Wechsler's tests for children. These tests differ from their predecessors in the way they offer an overall intelligence score as well as scores for various verbal and performance areas.

Question

piUnyJ+5PdUcRshkHtCEhjOeN35UTtt1ncSSOltogX5y1AtKoRUeQdKuEV932yQ4yVZUylvhT6UDw44Jys+FFMasSp4nw1uIjC9lyXqIfXlArADhG2Y7p1NFb15DObN9ldl1CzLP55fiCBEX7y9HLEEkoemWpW2lguEoWLGq6NE+bRzUoveHgJh6U13jKpb58x3tTlL755TggnM3AIKxIIz4rlr5nFySfpo6SLak4kW/MdWAt7e37e3ZaF9vKKun4CcyKxxvPpNphB1GfC7V6aAAuNam6bfhH1iDruUYAVKvQ4mS
ANSWER: The distribution of test scores often forms a normal (bell-shaped) curve around the central average score, with fewer and fewer scores at the extremes. Standardization establishes a basis for meaningful score comparisons by giving a test to a representative sample of future test-takers. Reliability is the extent to which a test yields consistent results (on two halves of the test, on alternative forms of the test, or when people are retested). Validity is the extent to which a test measures or predicts what it is supposed to. A test has content validity if it samples the pertinent behavior (as a driving test measures driving ability). It has predictive validity if it predicts a behavior it was designed to predict. (Aptitude tests have predictive ability if they can predict future achievements; their predictive power is best for the early school years.)

Question

h6JPHeDLWoXMniJFJXPZR+vy92rR820CMeHzxb+EeXxs9nmtCl6JxrgYCvMiRlYksLiZGKBwcYdjmMC+52PxQEW6ZNVwyuoS/hG2Ph32VhM11cOHrZwFT70rEsgG9nfJ4dX++F5WHj9b5WFXNJ9fectok0SkaslAS487pqesgmoD0AnJD1xgr/Imx6r/2At9nrmcqeyDCnXtjTqLvrlIbFf8o1ZImyEnV4masTnlHg0=
ANSWER: Cross-sectional studies (comparing people of different ages) and longitudinal studies (retesting the same group over a period of years) have shown that fluid intelligence declines in older adults, in part because neural processing slows. However, crystallized intelligence tends to increase.

Question

siuucgw62ohyqFwi9wFYHT0qTOZCDL4Zm6JV7AiGfPWEHE3WJspAucUahluMXBzUIcRwgyufmCGJUHffgs3oe7EZ6NxYH+TO5TiRqSlzDH7pEV/RQ5CNt3IpdM5BTgW8tLAR8lmcRZGY8FTZsQTFvH9jEvL0op17/SGDWDOk0siDg/mVF3GEf/rE0mfRJoCvFM9ZTN780dI5oqj4VbIibaJen+4c6hWFpCg1wd0GfVg=
ANSWER: The stability of intelligence test scores increases with age. At age 4, scores fluctuate somewhat but begin to predict adolescent and adult scores. By early adolescence, scores are very stable and predictive.

Question

OWaWxA4HhxzU7PQiWSix2vW4c0teNX7TEGNSd42IHoR/iW75qVjVyiVAbkg3XzfmVZqACt1kIPrcH4dcbHsBeRWt60qPSUHfSf5JDrrR80xY0V6SvHmi5+ICdCQoZfZvYnlOl8YPGdpsBBgBBTx0HMSw/9Ije1Q14glJ0DtsSims1iGLRcbjiKGq69k92sRttswliJXppH8/2k0R/namZg1QXI86G5T9S5bpPgY0PR0qNOSl6kFvPh8UChw=
ANSWER: At the low extreme are those with unusually low scores. An intelligence test score of or below 70 is one diagnostic criterion for the diagnosis of intellectual disability; other criteria are limited conceptual, social, and practical skills. One condition included in this category is Down syndrome, a developmental disorder caused by an extra copy of chromosome 21. People at the high-intelligence extreme tend to be healthy and well-adjusted, as well as unusually successful academically.

Terms and Concepts to Remember

Test yourself on these terms.

Question

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

Experience the Testing Effect

Test yourself repeatedly throughout your studies. This will not only help you figure out what you know and don’t know; the testing itself will help you learn and remember the information more effectively thanks to the testing effect.

Question 9.13

1. Charles Spearman suggested we have one 1+k3fn/itvti9k8czFjKmnPwlnzwoyLm2FojkRc7PN0= underlying success across a variety of intellectual abilities.

Question 9.14

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Question 9.15

3. Sternberg's three types of intelligence are jcu7xcy/AbvzqFkioG7epA== , pnKmWPeuu/jH4GFnbkXtRQ== , and +F5Yvexxnq1OrPnqbqjXaQ== .

Question 9.16

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Question 9.17

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Question 9.18

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Question 9.19

7. The Stanford-Binet, the Wechsler Adult Intelligence Scale, and the Wechsler Intelligence Scale for Children yield consistent results—on retesting, for example. In other words, these tests have high nE5ohSZpRxwgbB+Qe0mtUw== .

Question 9.20

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ANSWER: Writers' work relies more on crystallized intelligence, or accumulated knowledge, which increases with age. For top performance, scientists doing research may need more fluid intelligence (speedy and abstract reasoning), which tends to decrease with age.

Question 9.21

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Use image to create your personalized study plan, which will direct you to the resources that will help you most in image .