Chapter 9: Intelligence and Psychological Testing Key ...
Psychology- Chapter 9: Intelligence and Psychological Testing Key Concepts in Psychological Testing A psychological test is a standardized measure of a sample of a person‟s behaviour. They are used to measure the individual differences that exist among people in abilities, interests, and aspects of personality. Responses to a psychological test represent a sample of your behaviour. Principal Types of Tests Psychological tests are used extensively in research, but most of them were developed to serve a practical purpose outside of the laboratory. Most tests can be placed in one of two broad categories: mental ability tests and personality tests. Mental Ability Tests Intelligence tests measure general mental ability. They‟re intended to assess intellectual potential rather than previous learning or accumulated knowledge. Aptitude tests are also designed to measure potential more than knowledge, but they break mental ability into separate components. Thus, aptitude tests assess specific types of mental abilities. For example, the Differential Aptitude Tests assess verbal reasoning, numerical ability, abstract reasoning, perceptual speed, and accuracy, mechanical reasoning, space relationships, spelling and language usage. Like aptitude tests, achievement tests have a specific focus, but they‟re supposed to measure previous learning instead of potential. Thus, achievement tests gauge a person‟s mastery and knowledge of various subjects (such as reading, English, or history). Personality Tests Personality tests measure various aspects of personality, including motives, interests, values, and attitudes. Many psychologists prefer to call these tests personality scales because the questions do not have right and wrong answers. Standardization and Norms Standardization refers to the uniform procedures used in the administration and scoring of a test. All subjects get the same instructions, the same questions, and the same time limits so that their scores can be compared meaningfully. Test norms provide information about where a score on psychological tests ranks in relation to other scores on that test. Test norms are needed since everything in psychological tests are relevant. Psychological tests tell you how you score relative to other people.
A percentile score indicates the percentage of people who score at or below the score one has obtained. The sample of people that the norms are based on is called a test‟s standardization group. Ideally, tests norms are based on a large sample of people who were carefully selected to be representative of the broader population. Reliability Reliability refers to the measurement consistency of a test (or of other kinds of measurement technique). A test‟s reliability can be estimated in several ways. One widely used approach is to check test-retest reliability, which is estimated by comparing subject‟s scores on two administrations of a test. A correlation coefficient is a numerical index of the degree of relationship between two variables. In estimating testretest reliability, the two variables that must be correlated are the two sets of scores from the two administrations of the test. The closer the correlation comes to +1.00, the more reliable the test is. Validity Validity refers to the ability of a test to measure what it was designed to measure. The term validity is also used to refer to the accuracy or usefulness of the interferences or decisions based on a test. This broader conception of validity highlights the fact that a specific test might be valid for one purpose and invalid for another purpose. Content Validity Content validity refers to the degree to which the content of a test is representative of the domain it‟s supposed to cover. Content validity is evaluated with logic more than with statistics. Criterion-Related Validity Criterion-related validity is estimated by correlating subjects‟ scores on a test with their scores on an independent criterion (another measure) of the trait assessed by the test. Construct Validity Construct validity is the extent to which there is evidence that a test measures a particular hypothetical construct. Demonstrating construct validity can be complicated. It usually requires a series of studies that examine correlations between the test and various measures related to the trait in question. A thorough demonstration of construct validity requires looking at the relationship between a test and many other measures. The Evolution of Intelligence Testing Galton’s Studies of Hereditary Genius
In Galton‟s book Hereditary Genius, Galton concluded that success runs in families because great intelligence is passed from generation to generation through genetic inheritance. He assumed that the contents of the mind are built out of elementary sensations, and he hypothesized that exceptionally bright people should exhibit exceptional sensory acuity. His efforts met with little success. Research eventually showed that the sensory processes that he measured were largely unrelated to other criteria of mental ability that he was trying to predict, such as success in school or in professional life. Binet’s Breakthrough The Binet-Simon scale expressed a child‟s score in terms of “mental level” or “mental age”. A child‟s mental age indicated that he or she displayed the mental ability typical of a child of that chronological (actual) age. Binet realized that his scale was a somewhat crude initial effort at measuring mental ability. His death put an abrupt end to revising his scale, but other psychologists continued to build on Binet‟s work. Terman and the Stanford-Binet An intelligence quotient (IQ) is a child‟s mental age divided by chronological age, multiplied by 100. IQ= Mental Age X100 Chronological age The Stanford-Binet quickly became the world‟s foremost intelligence test and the standard of comparison for virtually all intelligence tests that followed. Wechsler’s Innovations Wechsler in 1939 published the first high-quality IQ test designed specifically for adults known as Wechsler Adult Intelligence Scale. The scales were characterized by at least two major innovations. First, Wechsler made his scales less dependent on subjects‟ verbal ability than the Stanford-Binet. He included many items that required nonverbal reasoning. To highlight the distinction between verbal and nonverbal ability, he formalized the computation of separate scores for verbal IQ, performance (nonverbal) IQ, and full-scale (total) IQ. Second, Wechsler discarded the intelligent quotient in favour of a new scoring scheme based on the normal distribution. This scoring system has been adopted by most other IQ tests, including the Stanford-Binet. Scores on intelligence tests are no longer based on actual quotient.
Intelligence Testing Today Today, psychologists and educators have many IQ tests available for their use. Basically, these tests fall into two categories: individual tests and group tests. Individual IQ tests are administered only by psychologists who have a special training for this purpose. The Stanford-Binet and the Wechsler scales are both individual IQ tests. Researchers have developed a number of IQ tests that can be administered to large groups of people at once because individual IQ tests are expensive and time-consuming to administer. Basic Questions about Intelligence Testing What Kinds of Questions Are on Intelligence Tests? Questions on IQ tests varies somewhat from test to test and depend on whether the test is intended for children or adults (or both) and whether the test is designed for individuals or groups. Wechsler subtests require subjects to furnish information, recognize vocabulary, and demonstrate basic memory. Generally speaking, examinees are required to manipulate words, numbers, and images through abstract reasoning. What Do Modern IQ Scores Mean? The normal distribution is a symmetric, bell-shaped curve that represents the pattern in which many characteristics are dispersed in the population. When a trait is normally distributed, most cases fall near the centre of the distribution (an average score) and the number of cases gradually declines as one moves away from the centre in either direction. Raw scores are translated into deviation IQ scores that locate subjects precisely within the normal distribution, using the standard deviation as the unit of measurement. The key point is that modern IQ scores indicate exactly where you fall in the normal distribution of intelligence. Thus, a score of 120 does not indicate that you answered 120 questions correctly. Nor does it mean that you have 120 “units” of intelligence. A deviation IQ score places you at a specific point in the normal distribution of intelligence. Do Intelligence Tests Measure Potential or Knowledge? IQ tests measure a blend of potential and knowledge. Test developers try to tilt the balance toward the assessment of potential as much as possible, but factual knowledge clearly has an impact on intelligence test scores. Do Intelligence Tests Have Adequate Reliability? IQ tests are exceptionally reliable. However, like other tests, they sample behaviour, and a specific testing may yield an unrepresentative score.
The most common problem is that low motivation or high anxiety may drag a person‟s score down on a particular occasion. Do Intelligence Tests Have Adequate Validity? IQ tests are valid measures of the kind of intelligence that‟s necessary to do well in academic work. But in a much broader sense, the validity of IQ tests is questionable. Intelligent behaviour falls into three categories: (1) verbal intelligence (2) practical intelligence and (3) social intelligence. People generally recognize three basic components of intelligence. For the most part, IQ tests assess only the first of these three components. Do Intelligence Tests Predict Vocational Success? People who score high on IQ tests are more likely than those who score low to end up in high-status jobs. Findings suggest that intelligence fosters vocational success, but the strength of the relationship is modest. There is far more debate about whether IQ scores are effective predictors of performance within a particular occupation. Research suggests that (1) there is a substantial correlation (about 0.50) between IQ scores and job performance, (2) this correlation varies somewhat depending on the complexity of a job‟s requirements but does not disappear even for low-level jobs, (3) this association holds up even when workers have more experience at their jobs, and (4) measures of specific mental abilities and personality traits are much less predictive of job performance than measures of intelligence. Are IQ Tests Widely Used in Other Cultures? Intelligence testing is largely a Western enterprise and IQ tests are not widely used in most non-Western cultures. One reason is that different cultures have different conceptions of intelligence. Extremes of Intelligence Mental Retardation/Intellectual Disability Mental retardation or intellectual disability refers to subnormal general mental ability accompanied by deficiencies in adaptive skills, originating before age 18. Levels of Retardation Mental retardation has traditionally been classified into 4 levels characterized as mild, moderate, severe, or profound. The vast majority of people diagnosed with intellectual disability fall in the mild category. Only about 15% of people diagnosed with intellectual disability exhibit the obvious mental deficiencies that most people envision when they think of retardation. The mental deficiency of children in the mild disability category often is not noticed until they have been in school a few years. Outside of school, many are considered normal.
Origins of Retardation Many organic conditions can cause mental retardation. For example, Down syndrome is a condition marked by distinctive physical characteristics (such as slanted eyes, stubby limbs, and thin hair) that is associated with mild to severe retardation. The FRM 1 gene contributes to the development of Fragile X syndrome (FXS), a common cause of hereditary mental retardation. In FXS there is a mutation in the inherited gene. Phenylketonuria is a metabolic disorder (due to an inherited enzyme deficiency) that can lead to intellectual disability if it is not caught and treated in infancy. In hydrocephaly, an excessive accumulation of cerebrospinal fluid in the skull destroys brain tissue and causes retardation. Diagnosticians are unable to pin down an organic cause for as many as 50% of cases. Giftedness Giftedness is widely misunderstood. This misunderstanding is a result, in part, of television and movies inaccurately portraying gifted children as social misfits and “nerds”. Identifying Gifted Children Experts consistently assert that giftedness should not be equated with high intelligence and they recommend that schools not rely too heavily on IQ tests to select gifted children. In practice, however, efforts to identify gifted children focus almost exclusively on IQ scores and rarely consider qualities such as creativity, leadership, or special talent. Most school districts consider children who fall in the upper 2%-3% of the IQ distribution to be gifted. Thus, the minimum IQ score for gifted programs usually falls somewhere around 130. Personal Qualities of the Gifted Study of gifted children by Lewis Terman begun in 1921. His original subject pool consisted of around 1500 youngsters who had an average IQ of 150. In comparison to subjects with normal IQ scores, Terman‟s gifted children were found to be above average in height, weight, strength, physical health, emotional adjustment, mental health, emotional stability, and social satisfaction throughout their adult years. However, some other lines of research raise some questions about this conclusion. Ellen Winner asserts that moderately gifted children (those with an IQ of 130-150) are very different from profoundly gifted children (those with an IQ above 180). She asserts that profoundly gifted children are often introverted and socially isolated. She also estimates that the incidence of interpersonal and emotional problems in this group is about twice as high as in other children.
Giftedness and Achievement in Life Terman‟s gifted children grew up to be very successful by conventional standards. By midlife they had produced 92 books, 235 patens, and nearly 2200 scientific articles. But, no one in the group achieved recognition for genius-level contributions. The concept of giftedness is applied to two very different groups. One consists of high-IQ children who are the cream of the crop in school. The other consists of eminent adults who make enduring contributions in their fields. Joseph Renzulli theorizes that this rarer form of giftedness depends on the intersection of three factors: high intelligence, high creativity, and high motivation. He emphasizes that high intelligence alone does not foster genuine greatness. Hidden gifted students often remain hidden because they underachieve in school—perhaps, in part, as a result of their attitudes toward school itself or because of the expectations of others. Heredity and Environment as Determinants of Intelligence Evidence for Hereditary Influence Family studies determine whether genetic influence on a trait is plausible, not whether it is certain. Researchers must turn to twin studies and adoption studies to obtain more definitive evidence on whether heredity affects intelligence. Twin Studies Identical twins tend to be quite similar in intelligence; the average correlation for identical twins (0.86) is very high. The average correlation for fraternal twins (0.60) is significantly lower. This correlation indicates that fraternal twins also tend to be similar in intelligence, but noticeably less so than identical twins. This supports the notion that IQ is inherited to a considerable degree. Although reared in different environments, these identical twins still display greater similarity in IQ (average correlation: 0.72) than fraternal twins reared together (average correlation: 0.60). Adoption Studies Relevant studies indicate that there is indeed more than chance similarity between adopted children and their biological parents. Heritability Estimates A heritability ratio is an estimate of the proportion of trait variability in a population that is determined by variations in genetic inheritance.
Heritability can be estimated for any trait. For example, the heritability of height is estimated to be around 90%. Heritability can be estimated in a variety of ways that appear logically and mathematically defensible. A few theorists, such as Arthur Jensen, maintain that the heritability of IQ ranges as high as 80%. That is, they believe that only about 20% of the variation in intelligence is attributable to environmental factors. Heritability estimates have certain limitations. First, a heritability estimate is a group statistic based on studies of trait variability within a specific group. A heritability estimate cannot be applied meaningfully to individuals. In other words, even if the heritability of intelligence is 60%, this does not mean that each individual‟s intelligence is 60% inherited. Second, the heritability of a specific trait may vary from one group to another, depending on a variety of factors. For instance, in a group with a given gene pool, heritability will increase if there‟s a shift toward rearing group members in more similar circumstances because the extent of environmental differences will be reduced. Third, it is crucial to understand that “there really is no single fixed value that represents any true, constant value for the heritability of IQ or anything else. Evidence for Environmental Influence Adoption Studies Adopted children show some resemblance to their adoptive parents in IQ. This similarity is usually attributed to the fact that their adoptive parents shape their environment. Adoption studies also indicate that siblings reared together are more similar in IQ than siblings reared apart. Environmental Deprivation and Enrichment If environment affects intelligence, children who are raised in substandard circumstances should experience a gradual decline in IQ as they grow older (since other children will be progressing more rapidly). This cumulative deprivation hypothesis was studies decades ago. Researchers studied children consigned to understaffed orphanages and children raised in poverty and isolation of the back hills of Appalachia. Generally, investigators did find that environmental deprivation led to the predicted erosion in IQ scores. Conversely, children removed from a deprived environment and placed in circumstances more conducive to learning should benefit from their environmental enrichment. Their IQ scores should gradually increase. Generational Changes: The Flynn Effect
Tests are renormed periodically with new standardization groups, so that the mean IQ always remains at 100. However, James Flynn noticed that the level of performance required to earn a score of 100 jumped upward every time the tests were renormed. He eventually gathered extensive data from 20 nations and demonstrated that IQ performance has been rising steadily all over the industrialized world since the 1930s. Thus, the performance that today would earn you an average score of 100 would have earned you an IQ score of about 120 back in the 1930s. Researchers have dubbed this as the “Flynn Effect” and they mostly agree on that the Flynn effect has to be attributed to environmental factors, as the modern world‟s gene pool could not have changed overnight (in evolutionary terms, 70 years is more like a fraction of a second). The Interaction of Heredity and Environment Theorists use the term reaction range to refer to these genetically determined limits on IQ (or other traits). According to this reaction-range model, children reared in high-quality environments that promote the development of intelligence should score near the top of their potential IQ range. Intelligence may be influenced by hundreds of specific genes, each of which may have a very small effect that is extremely difficult to detect with current technologies. Cultural Differences in IQ Scores The average IQ for many of the larger minority groups in the U.S. (such as blacks, Native Americans, and Hispanics) is somewhat lower than the average for whites. However, data from the standardization samples for the Stanford-Binet and Wechsler scales suggest that the gap between blacks and whites has shrunk about 4-7 points since the 1970‟s. There is relatively little argument about the existence of these group differences, variously referred to as racial, ethnic, or cultural differences in intelligence. The controversy concerns why the differences are found. Heritability as an Explanation Arthur Jensen causing a huge controversy by arguing that cultural differences in IQ are largely due to heredity. Jensen‟s argument was his analysis suggesting that the heritability of intelligence is about 80%. Essentially, he asserted (1) intelligence is largely „genetic in origin and (2) that, therefore, genetic factors are “strongly implicated” as the cause of ethnic differences in intelligence. The same situation comes into light 25 years later with Richard Herrnstein and Charles Murray with their book The Bell Curve. The implicit message throughout this book is that
disadvantaged groups cannot avoid their fate because it is their genetic destiny. Socioeconomic Disadvantage as an Explanation Many social scientists argue that minority students‟ IQ scores are depressed because these children tend to grow up in deprived environments that create a disadvantage—both in school and IQ tests. Lower-class children are more likely to come from large families and from single-parent homes, factors that may often limit the parental attention they receive. Racial Stereotype Vulnerability as an Explanation Claude Steele argues that derogatory stereotypes of stigmatized groups‟ intellectual capabilities create unique feelings of vulnerability in the educational area. These feelings of stereotype vulnerability can undermine group members‟ performance on tests, and other measures. These feelings may also create belonging uncertainty, doubts in their mind about the quality of their social bonds and relationships in these situations. Steele continues to say that people seem to blame their failures based on their sex, most often women. Cultural Bias on IQ Tests as an Explanation Some critics have argued that cultural differences in IQ scores are partly due to a cultural bias built in into IQ tests. They argue that because IQ tests are constructed by white, middle-class psychologists, they naturally draw on experience and knowledge typical of white, middle-class lifestyles, etc. Some data suggests that the IQ gap between whites and AfricanAmericans is due to cultural differences in knowledge due to disparities in exposure to information. New Directions in the Assessment and Study of Intelligence Increasing Emphasis on Specific Abilities Increased emphasis on the measurement of specific mental abilities as opposed to general mental ability. Factor analysis- the correlation among many variables are analyzed to identify closely related clusters of variables. Spearman concluded that all cognitive abilities share an important core factor, which he labelled g for general mental ability. In contrast, Thurstone found that he could carve intelligence into seven distinct factors called primary mental abilities: word fluency, verbal comprehension, spatial ability, perceptual speed, numerical ability, inductive reasoning, and memory. Proposed by Raymond Cattell and developed by John Horn, they suggested that g should be divided into fluid intelligence and crystallized intelligence.
Fluid intelligence involves reasoning ability, memory capacity, and speed of information processing. Crystallized intelligence involves ability to apply acquired knowledge and skills in problem solving. Exploring Biological Indexes of Intelligence Jensen measures reaction time (RT), using a panel of paired buttons and lights. Measures of inspection time assess how long it takes participants to make simple perceptual discriminations that meet a certain criterion of accuracy. An enriched environment can produce denser neural networks and heavier brains in laboratory rats. Hence, it is also possible in the opposite direction—that developing greater intelligence promotes larger brain size. Studies have yielded the same conclusion: Smarter people live longer. More intelligent people are better equipped to assimilate complex information on health risks, monitor subtle symptoms and seek appropriate care, manage health-related habits and behaviours effectively, minimize exposure to various hazards, etc, Investigating Cognitive Processes in Intelligent Behaviour The investigation of intelligence has been approached primarily from a testing perspective. This perspective emphasizes measuring the amount of intelligence people have and figuring out why some have more than others. In contrast, the cognitive perspective focuses on how people use their intelligence. Sternberg‟s Triarchic theory of human intelligence consists of three parts: the contextual, experiential, and componential subtheory, Sternberg argues that intelligence is a culturally defined concept. He asserts that different manifestations of intelligent behaviours are valued in different contexts. In his experiential subtheory, Sternberg explores the relationships between experience and intelligence. He emphasizes two factors as the hallmarks of intelligent behaviour. The first is the ability to deal effectively with novelty—new tasks, demands, and situations. Second factor is the ability to learn how to handle familiar tasks automatically and effortlessly. His componential subtheory describes three types of mental components and knowledge-acquisition components. Sternberg has asserted that there are three aspects of facets of what he calls “successful intelligence”: analytical intelligence, creative intelligence, and practical intelligence. Analytical intelligence involves abstract reasoning, evaluation, and judgment. It is the type of intelligence that
is crucial to most schoolwork and that is assessed by conventional IQ tests. Creative intelligence involves the ability to generate new ideas and to be inventive in dealing with novel problems. Practical intelligence involves the ability to deal effectively with the kinds of problems that people encounter in everyday life, such as on the job or at home. Sternberg and his colleagues have gathered data suggesting that (1) all three facets of intelligence can be measured reliably, (2) the three facets of intelligence are relatively independent (uncorrelated), and (3) the assessment of all three aspects of intelligence can improve the prediction of intelligent behaviour in the real world. Measuring Emotional Intelligence The measurement of emotional intelligence can enhance the prediction of success at school, at work, and in interpersonal relationships. Emotional intelligence consists of the ability to perceive and express emotion, assimilate emotion in thought, understand and reason with emotion, and regulate emotion. Includes four essential components. First, people need to be able to accurately perceive emotions in themselves and others and have the ability to express their own emotions effectively. Second, people need to be aware of how their emotions shape their thinking, decision making, and coping with stress. Third, people need to be able to understand and analyze their emotions, which may often be complex and contradictory. Fourth, people need to be able to regulate their emotions so that they can dampen negative emotions and make effective use of positive emotions. Personal Application The Nature of Creativity Creativity involves the generation of ideas that are original, novel, and useful. Does Creativity Depend on Divergent Thinking? In convergent thinking, one tries to narrow down a list of alternatives to converge on a single correct answer. In divergent thinking, one tries to expand the range of alternatives by generating many possible solutions. Critical Thinking Application Reification Reification occurs when a hypothetical, abstract concept is given a name and then treated as though it were concrete, tangible object.
A percentile score indicates the percentage of people who score at or below the score one has obtained. The sample of people that the norms are based on is called a test‟s standardization group. Ideally, tests norms are based on a large sample of people who were carefully selected to be representative of the broader population. Reliability Reliability refers to the measurement consistency of a test (or of other kinds of measurement technique). A test‟s reliability can be estimated in several ways. One widely used approach is to check test-retest reliability, which is estimated by comparing subject‟s scores on two administrations of a test. A correlation coefficient is a numerical index of the degree of relationship between two variables. In estimating testretest reliability, the two variables that must be correlated are the two sets of scores from the two administrations of the test. The closer the correlation comes to +1.00, the more reliable the test is. Validity Validity refers to the ability of a test to measure what it was designed to measure. The term validity is also used to refer to the accuracy or usefulness of the interferences or decisions based on a test. This broader conception of validity highlights the fact that a specific test might be valid for one purpose and invalid for another purpose. Content Validity Content validity refers to the degree to which the content of a test is representative of the domain it‟s supposed to cover. Content validity is evaluated with logic more than with statistics. Criterion-Related Validity Criterion-related validity is estimated by correlating subjects‟ scores on a test with their scores on an independent criterion (another measure) of the trait assessed by the test. Construct Validity Construct validity is the extent to which there is evidence that a test measures a particular hypothetical construct. Demonstrating construct validity can be complicated. It usually requires a series of studies that examine correlations between the test and various measures related to the trait in question. A thorough demonstration of construct validity requires looking at the relationship between a test and many other measures. The Evolution of Intelligence Testing Galton’s Studies of Hereditary Genius
In Galton‟s book Hereditary Genius, Galton concluded that success runs in families because great intelligence is passed from generation to generation through genetic inheritance. He assumed that the contents of the mind are built out of elementary sensations, and he hypothesized that exceptionally bright people should exhibit exceptional sensory acuity. His efforts met with little success. Research eventually showed that the sensory processes that he measured were largely unrelated to other criteria of mental ability that he was trying to predict, such as success in school or in professional life. Binet’s Breakthrough The Binet-Simon scale expressed a child‟s score in terms of “mental level” or “mental age”. A child‟s mental age indicated that he or she displayed the mental ability typical of a child of that chronological (actual) age. Binet realized that his scale was a somewhat crude initial effort at measuring mental ability. His death put an abrupt end to revising his scale, but other psychologists continued to build on Binet‟s work. Terman and the Stanford-Binet An intelligence quotient (IQ) is a child‟s mental age divided by chronological age, multiplied by 100. IQ= Mental Age X100 Chronological age The Stanford-Binet quickly became the world‟s foremost intelligence test and the standard of comparison for virtually all intelligence tests that followed. Wechsler’s Innovations Wechsler in 1939 published the first high-quality IQ test designed specifically for adults known as Wechsler Adult Intelligence Scale. The scales were characterized by at least two major innovations. First, Wechsler made his scales less dependent on subjects‟ verbal ability than the Stanford-Binet. He included many items that required nonverbal reasoning. To highlight the distinction between verbal and nonverbal ability, he formalized the computation of separate scores for verbal IQ, performance (nonverbal) IQ, and full-scale (total) IQ. Second, Wechsler discarded the intelligent quotient in favour of a new scoring scheme based on the normal distribution. This scoring system has been adopted by most other IQ tests, including the Stanford-Binet. Scores on intelligence tests are no longer based on actual quotient.
Intelligence Testing Today Today, psychologists and educators have many IQ tests available for their use. Basically, these tests fall into two categories: individual tests and group tests. Individual IQ tests are administered only by psychologists who have a special training for this purpose. The Stanford-Binet and the Wechsler scales are both individual IQ tests. Researchers have developed a number of IQ tests that can be administered to large groups of people at once because individual IQ tests are expensive and time-consuming to administer. Basic Questions about Intelligence Testing What Kinds of Questions Are on Intelligence Tests? Questions on IQ tests varies somewhat from test to test and depend on whether the test is intended for children or adults (or both) and whether the test is designed for individuals or groups. Wechsler subtests require subjects to furnish information, recognize vocabulary, and demonstrate basic memory. Generally speaking, examinees are required to manipulate words, numbers, and images through abstract reasoning. What Do Modern IQ Scores Mean? The normal distribution is a symmetric, bell-shaped curve that represents the pattern in which many characteristics are dispersed in the population. When a trait is normally distributed, most cases fall near the centre of the distribution (an average score) and the number of cases gradually declines as one moves away from the centre in either direction. Raw scores are translated into deviation IQ scores that locate subjects precisely within the normal distribution, using the standard deviation as the unit of measurement. The key point is that modern IQ scores indicate exactly where you fall in the normal distribution of intelligence. Thus, a score of 120 does not indicate that you answered 120 questions correctly. Nor does it mean that you have 120 “units” of intelligence. A deviation IQ score places you at a specific point in the normal distribution of intelligence. Do Intelligence Tests Measure Potential or Knowledge? IQ tests measure a blend of potential and knowledge. Test developers try to tilt the balance toward the assessment of potential as much as possible, but factual knowledge clearly has an impact on intelligence test scores. Do Intelligence Tests Have Adequate Reliability? IQ tests are exceptionally reliable. However, like other tests, they sample behaviour, and a specific testing may yield an unrepresentative score.
The most common problem is that low motivation or high anxiety may drag a person‟s score down on a particular occasion. Do Intelligence Tests Have Adequate Validity? IQ tests are valid measures of the kind of intelligence that‟s necessary to do well in academic work. But in a much broader sense, the validity of IQ tests is questionable. Intelligent behaviour falls into three categories: (1) verbal intelligence (2) practical intelligence and (3) social intelligence. People generally recognize three basic components of intelligence. For the most part, IQ tests assess only the first of these three components. Do Intelligence Tests Predict Vocational Success? People who score high on IQ tests are more likely than those who score low to end up in high-status jobs. Findings suggest that intelligence fosters vocational success, but the strength of the relationship is modest. There is far more debate about whether IQ scores are effective predictors of performance within a particular occupation. Research suggests that (1) there is a substantial correlation (about 0.50) between IQ scores and job performance, (2) this correlation varies somewhat depending on the complexity of a job‟s requirements but does not disappear even for low-level jobs, (3) this association holds up even when workers have more experience at their jobs, and (4) measures of specific mental abilities and personality traits are much less predictive of job performance than measures of intelligence. Are IQ Tests Widely Used in Other Cultures? Intelligence testing is largely a Western enterprise and IQ tests are not widely used in most non-Western cultures. One reason is that different cultures have different conceptions of intelligence. Extremes of Intelligence Mental Retardation/Intellectual Disability Mental retardation or intellectual disability refers to subnormal general mental ability accompanied by deficiencies in adaptive skills, originating before age 18. Levels of Retardation Mental retardation has traditionally been classified into 4 levels characterized as mild, moderate, severe, or profound. The vast majority of people diagnosed with intellectual disability fall in the mild category. Only about 15% of people diagnosed with intellectual disability exhibit the obvious mental deficiencies that most people envision when they think of retardation. The mental deficiency of children in the mild disability category often is not noticed until they have been in school a few years. Outside of school, many are considered normal.
Origins of Retardation Many organic conditions can cause mental retardation. For example, Down syndrome is a condition marked by distinctive physical characteristics (such as slanted eyes, stubby limbs, and thin hair) that is associated with mild to severe retardation. The FRM 1 gene contributes to the development of Fragile X syndrome (FXS), a common cause of hereditary mental retardation. In FXS there is a mutation in the inherited gene. Phenylketonuria is a metabolic disorder (due to an inherited enzyme deficiency) that can lead to intellectual disability if it is not caught and treated in infancy. In hydrocephaly, an excessive accumulation of cerebrospinal fluid in the skull destroys brain tissue and causes retardation. Diagnosticians are unable to pin down an organic cause for as many as 50% of cases. Giftedness Giftedness is widely misunderstood. This misunderstanding is a result, in part, of television and movies inaccurately portraying gifted children as social misfits and “nerds”. Identifying Gifted Children Experts consistently assert that giftedness should not be equated with high intelligence and they recommend that schools not rely too heavily on IQ tests to select gifted children. In practice, however, efforts to identify gifted children focus almost exclusively on IQ scores and rarely consider qualities such as creativity, leadership, or special talent. Most school districts consider children who fall in the upper 2%-3% of the IQ distribution to be gifted. Thus, the minimum IQ score for gifted programs usually falls somewhere around 130. Personal Qualities of the Gifted Study of gifted children by Lewis Terman begun in 1921. His original subject pool consisted of around 1500 youngsters who had an average IQ of 150. In comparison to subjects with normal IQ scores, Terman‟s gifted children were found to be above average in height, weight, strength, physical health, emotional adjustment, mental health, emotional stability, and social satisfaction throughout their adult years. However, some other lines of research raise some questions about this conclusion. Ellen Winner asserts that moderately gifted children (those with an IQ of 130-150) are very different from profoundly gifted children (those with an IQ above 180). She asserts that profoundly gifted children are often introverted and socially isolated. She also estimates that the incidence of interpersonal and emotional problems in this group is about twice as high as in other children.
Giftedness and Achievement in Life Terman‟s gifted children grew up to be very successful by conventional standards. By midlife they had produced 92 books, 235 patens, and nearly 2200 scientific articles. But, no one in the group achieved recognition for genius-level contributions. The concept of giftedness is applied to two very different groups. One consists of high-IQ children who are the cream of the crop in school. The other consists of eminent adults who make enduring contributions in their fields. Joseph Renzulli theorizes that this rarer form of giftedness depends on the intersection of three factors: high intelligence, high creativity, and high motivation. He emphasizes that high intelligence alone does not foster genuine greatness. Hidden gifted students often remain hidden because they underachieve in school—perhaps, in part, as a result of their attitudes toward school itself or because of the expectations of others. Heredity and Environment as Determinants of Intelligence Evidence for Hereditary Influence Family studies determine whether genetic influence on a trait is plausible, not whether it is certain. Researchers must turn to twin studies and adoption studies to obtain more definitive evidence on whether heredity affects intelligence. Twin Studies Identical twins tend to be quite similar in intelligence; the average correlation for identical twins (0.86) is very high. The average correlation for fraternal twins (0.60) is significantly lower. This correlation indicates that fraternal twins also tend to be similar in intelligence, but noticeably less so than identical twins. This supports the notion that IQ is inherited to a considerable degree. Although reared in different environments, these identical twins still display greater similarity in IQ (average correlation: 0.72) than fraternal twins reared together (average correlation: 0.60). Adoption Studies Relevant studies indicate that there is indeed more than chance similarity between adopted children and their biological parents. Heritability Estimates A heritability ratio is an estimate of the proportion of trait variability in a population that is determined by variations in genetic inheritance.
Heritability can be estimated for any trait. For example, the heritability of height is estimated to be around 90%. Heritability can be estimated in a variety of ways that appear logically and mathematically defensible. A few theorists, such as Arthur Jensen, maintain that the heritability of IQ ranges as high as 80%. That is, they believe that only about 20% of the variation in intelligence is attributable to environmental factors. Heritability estimates have certain limitations. First, a heritability estimate is a group statistic based on studies of trait variability within a specific group. A heritability estimate cannot be applied meaningfully to individuals. In other words, even if the heritability of intelligence is 60%, this does not mean that each individual‟s intelligence is 60% inherited. Second, the heritability of a specific trait may vary from one group to another, depending on a variety of factors. For instance, in a group with a given gene pool, heritability will increase if there‟s a shift toward rearing group members in more similar circumstances because the extent of environmental differences will be reduced. Third, it is crucial to understand that “there really is no single fixed value that represents any true, constant value for the heritability of IQ or anything else. Evidence for Environmental Influence Adoption Studies Adopted children show some resemblance to their adoptive parents in IQ. This similarity is usually attributed to the fact that their adoptive parents shape their environment. Adoption studies also indicate that siblings reared together are more similar in IQ than siblings reared apart. Environmental Deprivation and Enrichment If environment affects intelligence, children who are raised in substandard circumstances should experience a gradual decline in IQ as they grow older (since other children will be progressing more rapidly). This cumulative deprivation hypothesis was studies decades ago. Researchers studied children consigned to understaffed orphanages and children raised in poverty and isolation of the back hills of Appalachia. Generally, investigators did find that environmental deprivation led to the predicted erosion in IQ scores. Conversely, children removed from a deprived environment and placed in circumstances more conducive to learning should benefit from their environmental enrichment. Their IQ scores should gradually increase. Generational Changes: The Flynn Effect
Tests are renormed periodically with new standardization groups, so that the mean IQ always remains at 100. However, James Flynn noticed that the level of performance required to earn a score of 100 jumped upward every time the tests were renormed. He eventually gathered extensive data from 20 nations and demonstrated that IQ performance has been rising steadily all over the industrialized world since the 1930s. Thus, the performance that today would earn you an average score of 100 would have earned you an IQ score of about 120 back in the 1930s. Researchers have dubbed this as the “Flynn Effect” and they mostly agree on that the Flynn effect has to be attributed to environmental factors, as the modern world‟s gene pool could not have changed overnight (in evolutionary terms, 70 years is more like a fraction of a second). The Interaction of Heredity and Environment Theorists use the term reaction range to refer to these genetically determined limits on IQ (or other traits). According to this reaction-range model, children reared in high-quality environments that promote the development of intelligence should score near the top of their potential IQ range. Intelligence may be influenced by hundreds of specific genes, each of which may have a very small effect that is extremely difficult to detect with current technologies. Cultural Differences in IQ Scores The average IQ for many of the larger minority groups in the U.S. (such as blacks, Native Americans, and Hispanics) is somewhat lower than the average for whites. However, data from the standardization samples for the Stanford-Binet and Wechsler scales suggest that the gap between blacks and whites has shrunk about 4-7 points since the 1970‟s. There is relatively little argument about the existence of these group differences, variously referred to as racial, ethnic, or cultural differences in intelligence. The controversy concerns why the differences are found. Heritability as an Explanation Arthur Jensen causing a huge controversy by arguing that cultural differences in IQ are largely due to heredity. Jensen‟s argument was his analysis suggesting that the heritability of intelligence is about 80%. Essentially, he asserted (1) intelligence is largely „genetic in origin and (2) that, therefore, genetic factors are “strongly implicated” as the cause of ethnic differences in intelligence. The same situation comes into light 25 years later with Richard Herrnstein and Charles Murray with their book The Bell Curve. The implicit message throughout this book is that
disadvantaged groups cannot avoid their fate because it is their genetic destiny. Socioeconomic Disadvantage as an Explanation Many social scientists argue that minority students‟ IQ scores are depressed because these children tend to grow up in deprived environments that create a disadvantage—both in school and IQ tests. Lower-class children are more likely to come from large families and from single-parent homes, factors that may often limit the parental attention they receive. Racial Stereotype Vulnerability as an Explanation Claude Steele argues that derogatory stereotypes of stigmatized groups‟ intellectual capabilities create unique feelings of vulnerability in the educational area. These feelings of stereotype vulnerability can undermine group members‟ performance on tests, and other measures. These feelings may also create belonging uncertainty, doubts in their mind about the quality of their social bonds and relationships in these situations. Steele continues to say that people seem to blame their failures based on their sex, most often women. Cultural Bias on IQ Tests as an Explanation Some critics have argued that cultural differences in IQ scores are partly due to a cultural bias built in into IQ tests. They argue that because IQ tests are constructed by white, middle-class psychologists, they naturally draw on experience and knowledge typical of white, middle-class lifestyles, etc. Some data suggests that the IQ gap between whites and AfricanAmericans is due to cultural differences in knowledge due to disparities in exposure to information. New Directions in the Assessment and Study of Intelligence Increasing Emphasis on Specific Abilities Increased emphasis on the measurement of specific mental abilities as opposed to general mental ability. Factor analysis- the correlation among many variables are analyzed to identify closely related clusters of variables. Spearman concluded that all cognitive abilities share an important core factor, which he labelled g for general mental ability. In contrast, Thurstone found that he could carve intelligence into seven distinct factors called primary mental abilities: word fluency, verbal comprehension, spatial ability, perceptual speed, numerical ability, inductive reasoning, and memory. Proposed by Raymond Cattell and developed by John Horn, they suggested that g should be divided into fluid intelligence and crystallized intelligence.
Fluid intelligence involves reasoning ability, memory capacity, and speed of information processing. Crystallized intelligence involves ability to apply acquired knowledge and skills in problem solving. Exploring Biological Indexes of Intelligence Jensen measures reaction time (RT), using a panel of paired buttons and lights. Measures of inspection time assess how long it takes participants to make simple perceptual discriminations that meet a certain criterion of accuracy. An enriched environment can produce denser neural networks and heavier brains in laboratory rats. Hence, it is also possible in the opposite direction—that developing greater intelligence promotes larger brain size. Studies have yielded the same conclusion: Smarter people live longer. More intelligent people are better equipped to assimilate complex information on health risks, monitor subtle symptoms and seek appropriate care, manage health-related habits and behaviours effectively, minimize exposure to various hazards, etc, Investigating Cognitive Processes in Intelligent Behaviour The investigation of intelligence has been approached primarily from a testing perspective. This perspective emphasizes measuring the amount of intelligence people have and figuring out why some have more than others. In contrast, the cognitive perspective focuses on how people use their intelligence. Sternberg‟s Triarchic theory of human intelligence consists of three parts: the contextual, experiential, and componential subtheory, Sternberg argues that intelligence is a culturally defined concept. He asserts that different manifestations of intelligent behaviours are valued in different contexts. In his experiential subtheory, Sternberg explores the relationships between experience and intelligence. He emphasizes two factors as the hallmarks of intelligent behaviour. The first is the ability to deal effectively with novelty—new tasks, demands, and situations. Second factor is the ability to learn how to handle familiar tasks automatically and effortlessly. His componential subtheory describes three types of mental components and knowledge-acquisition components. Sternberg has asserted that there are three aspects of facets of what he calls “successful intelligence”: analytical intelligence, creative intelligence, and practical intelligence. Analytical intelligence involves abstract reasoning, evaluation, and judgment. It is the type of intelligence that
is crucial to most schoolwork and that is assessed by conventional IQ tests. Creative intelligence involves the ability to generate new ideas and to be inventive in dealing with novel problems. Practical intelligence involves the ability to deal effectively with the kinds of problems that people encounter in everyday life, such as on the job or at home. Sternberg and his colleagues have gathered data suggesting that (1) all three facets of intelligence can be measured reliably, (2) the three facets of intelligence are relatively independent (uncorrelated), and (3) the assessment of all three aspects of intelligence can improve the prediction of intelligent behaviour in the real world. Measuring Emotional Intelligence The measurement of emotional intelligence can enhance the prediction of success at school, at work, and in interpersonal relationships. Emotional intelligence consists of the ability to perceive and express emotion, assimilate emotion in thought, understand and reason with emotion, and regulate emotion. Includes four essential components. First, people need to be able to accurately perceive emotions in themselves and others and have the ability to express their own emotions effectively. Second, people need to be aware of how their emotions shape their thinking, decision making, and coping with stress. Third, people need to be able to understand and analyze their emotions, which may often be complex and contradictory. Fourth, people need to be able to regulate their emotions so that they can dampen negative emotions and make effective use of positive emotions. Personal Application The Nature of Creativity Creativity involves the generation of ideas that are original, novel, and useful. Does Creativity Depend on Divergent Thinking? In convergent thinking, one tries to narrow down a list of alternatives to converge on a single correct answer. In divergent thinking, one tries to expand the range of alternatives by generating many possible solutions. Critical Thinking Application Reification Reification occurs when a hypothetical, abstract concept is given a name and then treated as though it were concrete, tangible object.
