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84-629: CAS development began with an attempt to offer an alternative to the IQ test (Das, Kirby & Jarman, 1975, 1979). Developed and published in 1997 by J.P. Das , PhD of the University of Alberta and Jack Naglieri , PhD, then at Ohio State University , the CAS has its theoretical bases both in the neuropsychology of Luria as well as in cognitive psychology . CAS is based on the planning, attention-arousal, simultaneous and successive (PASS) cognitive processing theory (or

168-418: A cohort effect rather than a true aging effect. A variety of studies of IQ and aging have been conducted since the norming of the first Wechsler Intelligence Scale drew attention to IQ differences in different age groups of adults. Both cohort effects (the birth year of the test-takers) and practice effects (test-takers taking the same form of IQ test more than once) must be controlled to gain accurate data. It

252-446: A normal distribution with mean 100 and standard deviation 15. While one standard deviation is 15 points, and two SDs are 30 points, and so on, this does not imply that mental ability is linearly related to IQ, such that IQ 50 would mean half the cognitive ability of IQ 100. In particular, IQ points are not percentage points. Psychometricians generally regard IQ tests as having high statistical reliability . Reliability represents

336-457: A common strength in abstract reasoning across the test's item content. During World War I, the Army needed a way to evaluate and assign recruits to appropriate tasks. This led to the development of several mental tests by Robert Yerkes , who worked with major hereditarians of American psychometrics—including Terman, Goddard—to write the test. The testing generated controversy and much public debate in

420-620: A concept of intelligence on IQ test scores alone neglects other important aspects of mental ability. Robert Sternberg , another significant critic of IQ as the main measure of human cognitive abilities, argued that reducing the concept of intelligence to the measure of g does not fully account for the different skills and knowledge types that produce success in human society. Despite these objections, clinical psychologists generally regard IQ scores as having sufficient statistical validity for many clinical purposes. Differential item functioning (DIF), sometimes referred to as measurement bias,

504-420: A concrete measure of intelligence cannot be achieved given the abstract nature of the concept of "intelligence". IQ scores have been shown to be associated with such factors as nutrition , parental socioeconomic status , morbidity and mortality , parental social status , and perinatal environment . While the heritability of IQ has been investigated for nearly a century, there is still debate about

588-551: A continuous performance test, and a more cognitively loaded vigilance test (Das, Naglieri & Kirby, 1994). In regard to Executive Functions, one would notice that elements of it are already included in CAS ;: Expressive attention (Stroop) = inhibition of response; Planned Connection (Trails) = shifting. But the existing Planning scale must be supplemented by tests of complex planning (Das, Kar & Parrila, 1996), and so-called 'hot' tests that involve affective decision making, such as

672-742: A merging of the Gf-Gc theory of Cattell and Horn with Carroll's Three-Stratum theory has led to the Cattell–Horn–Carroll theory (CHC Theory), with g as the top of the hierarchy, ten broad abilities below, and further subdivided into seventy narrow abilities on the third stratum. CHC Theory has greatly influenced many of the current broad IQ tests. Modern tests do not necessarily measure all of these broad abilities. For example, quantitative knowledge and reading and writing ability may be seen as measures of school achievement and not IQ. Decision speed may be difficult to measure without special equipment. g

756-464: A model of intelligence that included seven unrelated factors (verbal comprehension, word fluency, number facility, spatial visualization, associative memory, perceptual speed, reasoning, and induction). While not widely used, Thurstone's model influenced later theories. David Wechsler produced the first version of his test in 1939. It gradually became more popular and overtook the Stanford–Binet in

840-444: A particular stimulus, ignoring distractions, and maintaining vigilance. Simultaneous processing involves the integration of stimuli into a group and requires the observation of relationships. Successive processing involves the integration of stimuli into serial order. The planning and attention/arousal components comes from structures located in the frontal lobe, and the simultaneous and successive processes come from structures located in

924-399: A resurgence as a voluntary means of selective reproduction, with some calling them " new eugenics ". As it becomes possible to test for and correlate genes with IQ (and its proxies), ethicists and embryonic genetic testing companies are attempting to understand the ways in which the technology can be ethically deployed. Raymond Cattell (1941) proposed two types of cognitive abilities in

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1008-422: A revision of Spearman's concept of general intelligence. Fluid intelligence (Gf) was hypothesized as the ability to solve novel problems by using reasoning, and crystallized intelligence (Gc) was hypothesized as a knowledge-based ability that was very dependent on education and experience. In addition, fluid intelligence was hypothesized to decline with age, while crystallized intelligence was largely resistant to

1092-463: A single general ability factor and a large number of narrow task-specific ability factors. Spearman named it g for "general factor" and labeled the specific factors or abilities for specific tasks s . In any collection of test items that make up an IQ test, the score that best measures g is the composite score that has the highest correlations with all the item scores. Typically, the " g -loaded" composite score of an IQ test battery appears to involve

1176-435: A six-year-old child who passed all the tasks usually passed by six-year-olds—but nothing beyond—would have a mental age that matched his chronological age, 6.0. (Fancher, 1985). Binet and Simon thought that intelligence was multifaceted, but came under the control of practical judgment. In Binet and Simon's view, there were limitations with the scale and they stressed what they saw as the remarkable diversity of intelligence and

1260-499: A strong consensus of mainstream science, though fringe figures continue to promote them in pseudo-scholarship and popular culture. Historically, even before IQ tests were devised, there were attempts to classify people into intelligence categories by observing their behavior in daily life. Those other forms of behavioral observation are still important for validating classifications based primarily on IQ test scores. Both intelligence classification by observation of behavior outside

1344-871: A total of 120 types of intelligence. It was popular in the 1970s and early 1980s, but faded owing to both practical problems and theoretical criticisms. Alexander Luria 's earlier work on neuropsychological processes led to the PASS theory (1997). It argued that only looking at one general factor was inadequate for researchers and clinicians who worked with learning disabilities, attention disorders, intellectual disability, and interventions for such disabilities. The PASS model covers four kinds of processes (planning process, attention/arousal process, simultaneous processing, and successive processing). The planning processes involve decision making, problem solving, and performing activities and require goal setting and self-monitoring. The attention/arousal process involves selectively attending to

1428-405: A variety of shapes; it is similar to Progressive Matrices. Verbal spatial relations subtest measures the comprehension of logical and grammatical descriptions of spatial relationships. In this subtest, the child is presented with six drawings, arranged in a specific spatial manner, and a printed question (e.g., show me the triangle to the left of the circle). The child is instructed to choose one of

1512-400: Is a hierarchical model with three levels. The bottom stratum consists of narrow abilities that are highly specialized (e.g., induction, spelling ability). The second stratum consists of broad abilities. Carroll identified eight second-stratum abilities. Carroll accepted Spearman's concept of general intelligence, for the most part, as a representation of the uppermost, third stratum. In 1999,

1596-519: Is a mental process that involves focusing on selected aspects of external events, internal events, or stimuli. Attention is controlled by intentions and goals. The Attention scale includes the expressive attention, number detection, and receptive attention subtests. Expressive attention (a variation of the Stroop test) has two forms, one for children 7 years and younger, and the other 8 & over. The receptive attention subtest contains two separate tasks; in

1680-571: Is a phenomenon when participants from different groups (e.g. gender, race, disability) with the same latent abilities give different answers to specific questions on the same IQ test. DIF analysis measures such specific items on a test alongside measuring participants' latent abilities on other similar questions. A consistent different group response to a specific question among similar types of questions can indicate an effect of DIF. It does not count as differential item functioning if both groups have an equally valid chance of giving different responses to

1764-607: Is an 8-item timed subtest that requires the child to repeat a string of 3 common words, such as dog-girl-book, over and over again as fast as possible until asked to stop. The score is the time it takes the child to complete 10 repetitions before stopping. CAS is used for understanding cognitive development of typical and atypical children, as well as cognitive impairment in adults. It has been used for research, diagnosis, and clinical evaluation by several professionals including educational and school psychologists because it provides good guidelines for educational interventions. Research on

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1848-407: Is involved whenever information must be remembered or completed in a specific order or sequence. The Successive scale has word series, sentence repetition, and sentence questions. In word series, the examiner reads the child a series of words and then asks to repeat the words in the same order. Sentence repetition requires the child to read 20 sentences aloud one by one. After each sentence is read,

1932-584: Is now similar to the Wechsler in several aspects, but the Wechsler continues to be the most popular test in the United States. Eugenics , a set of beliefs and practices aimed at improving the genetic quality of the human population by excluding people and groups judged to be inferior and promoting those judged to be superior, played a significant role in the history and culture of the United States during

2016-613: Is perhaps the first battery of commercially available tests to provide a psychometric assessment of cognitive processes. K-ABC has used several references to the early research of Das and his colleagues (Das, Kirby & Jarman, 1979) on simultaneous and successive processing, a precursor to PASS theory. KABC did not assess the Arousal-Attention, and Planning functions, as CAS did, until K-ABC II appeared in 2004. The latter provides two theoretical bases, one of them in Luria (1966) and by default,

2100-483: Is set so performance at the population median results in a score of IQ 100. The phenomenon of rising raw score performance means if test-takers are scored by a constant standard scoring rule, IQ test scores have been rising at an average rate of around three IQ points per decade. This phenomenon was named the Flynn effect in the book The Bell Curve after James R. Flynn , the author who did the most to bring this phenomenon to

2184-1154: Is the use of CAS tests for fair assessment of minorities (Naglieri, 2005) and First Nation children whose chronic weakness in reading has been identified as a successive processing deficit compounded by poor home literacy (Das, Janzen & Georgiou, 2007) both of which can be improved through PASS-related intervention (Hayward, Das & Janzen, 2007). Additionally, CAS with supplementary tests has been found useful for research related to executive decision making in management (Das, Kar, & Parrila, 1996). CAS withstands adaptation and translation into other languages. CAS in Dutch, Italian, Japanese, Korean, Spanish (Castillian), Norwegian and Swedish are commercially available. In addition, CAS has been used in Chinese, Greek, Norwegian and Dutch research. The CAS meets at least two challenges, first in terms of its factor-analytic purity (Naglieri & Das, 1997 Interpretive handbook), and second in extending its scope by supplementary tests, especially for assessment of Executive Functions. The validity of CAS comprising

2268-597: Is unclear whether any lifestyle intervention can preserve fluid intelligence into older ages. Environmental and genetic factors play a role in determining IQ. Their relative importance has been the subject of much research and debate. The general figure for the heritability of IQ, according to an American Psychological Association report, is 0.45 for children, and rises to around 0.75 for late adolescents and adults. Heritability measures for g factor in infancy are as low as 0.2, around 0.4 in middle childhood, and as high as 0.9 in adulthood. One proposed explanation

2352-531: The Binet–Simon Intelligence test , which focused on verbal abilities . It was intended to identify "mental retardation" in school children, but in specific contradistinction to claims made by psychiatrists that these children were "sick" (not "slow") and should therefore be removed from school and cared for in asylums. The score on the Binet–Simon scale would reveal the child's mental age . For example,

2436-522: The PASS Theory of Intelligence ), a modern theory within the information-processing framework (Das, Naglieri & Kirby, 1994). Roots of CAS are in Luria's (1973) organization of cognitive functions in the brain as well as in cognitive psychology of Baddeley, Estes, Posner and other contemporary psychologists. Their work has guided the selection and interpretation of CAS tests. The Kaufman assessment battery for children or KABC by ( Alan S. Kaufman , 1983 )

2520-724: The Progressive Era , from the late 19th century until US involvement in World War II . The American eugenics movement was rooted in the biological determinist ideas of the British Scientist Sir Francis Galton . In 1883, Galton first used the word eugenics to describe the biological improvement of human genes and the concept of being "well-born". He believed that differences in a person's ability were acquired primarily through genetics and that eugenics could be implemented through selective breeding in order for

2604-589: The WAIS-R test may contain cultural influences that reduce the validity of the WAIS-R as a measure of cognitive ability for Mexican American students," indicating a weaker positive correlation relative to sampled white students. Other recent studies have questioned the culture-fairness of IQ tests when used in South Africa. Standard intelligence tests, such as the Stanford–Binet, are often inappropriate for autistic children;

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2688-436: The proximal development of children, originated in the writings of psychologist Lev Vygotsky (1896–1934) during his last two years of his life. According to Vygotsky, the maximum level of complexity and difficulty of problems that a child is capable to solve under some guidance indicates their level of potential development. The difference between this level of potential and the lower level of unassisted performance indicates

2772-504: The 1960s. It has been revised several times, as is common for IQ tests, to incorporate new research. One explanation is that psychologists and educators wanted more information than the single score from the Binet. Wechsler's ten or more subtests provided this. Another is that the Stanford–Binet test reflected mostly verbal abilities, while the Wechsler test also reflected nonverbal abilities. The Stanford–Binet has also been revised several times and

2856-415: The 4 PASS constructs is adequately supported by several books and studies (Das, Naglieri, & Kirby, 1994; Das, Kar & Parilla, 1996; Das, 2009). The CAS Interpretive Handbook, (Naglieri and Das, 1997) reported information about the factor structure of the CAS providing evidence that the PASS four-factor solution was the best solution based on the convergence of factor-analytic results, clinical utility of

2940-527: The 4 PASS processes) and the other in Cattell-Horn-Carroll model (CHC) which is essentially an elaboration of fluid and crystallized intelligence (McGrew 2005). Some may consider this a strength of KABC-II. However, two important features of CAS have set it apart from ability measures within fluid and crystallized abilities of CHC, and verbal-performance IQ: The CAS standard battery consists of three subtests for each PASS Scale (12 subtests in all) whereas

3024-446: The 95% confidence interval may be greater than 40 points, potentially complicating the accuracy of diagnoses of intellectual disability. By the same token, high IQ scores are also significantly less reliable than those near to the population median. Reports of IQ scores much higher than 160 are considered dubious. Reliability and validity are very different concepts. While reliability reflects reproducibility, validity refers to whether

3108-464: The Flynn effect demolishes the fears that IQ would be decreased. He also asks whether it represents a real increase in intelligence beyond IQ scores. A 2011 psychology textbook, lead authored by Harvard Psychologist Professor Daniel Schacter , noted that humans' inherited intelligence could be going down while acquired intelligence goes up. Research has suggested that the Flynn effect has slowed or reversed course in some Western countries beginning in

3192-444: The US eugenics movement to eliminate "undesirable" traits. Goddard used the term " feeble-minded " to refer to people who did not perform well on the test. He argued that "feeble-mindedness" was caused by heredity, and thus feeble-minded people should be prevented from giving birth, either by institutional isolation or sterilization surgeries. At first, sterilization targeted the disabled, but

3276-456: The United States. Nonverbal or "performance" tests were developed for those who could not speak English or were suspected of malingering. Based on Goddard's translation of the Binet–Simon test, the tests had an impact in screening men for officer training: ...the tests did have a strong impact in some areas, particularly in screening men for officer training. At the start of the war, the army and national guard maintained nine thousand officers. By

3360-404: The alternative of using developmental or adaptive skills measures are relatively poor measures of intelligence in autistic children, and may have resulted in incorrect claims that a majority of autistic children are of low intelligence. Since the early 20th century, raw scores on IQ tests have increased in most parts of the world. When a new version of an IQ test is normed, the standard scoring

3444-416: The attention of psychologists. Researchers have been exploring the issue of whether the Flynn effect is equally strong on performance of all kinds of IQ test items, whether the effect may have ended in some developed nations, whether there are social subgroup differences in the effect, and what possible causes of the effect might be. A 2011 textbook, IQ and Human Intelligence , by N. J. Mackintosh , noted

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3528-648: The banner of dynamic assessment , which seeks to measure developmental potential (for instance, in the work of Reuven Feuerstein and his associates, who has criticized standard IQ testing for its putative assumption or acceptance of "fixed and immutable" characteristics of intelligence or cognitive functioning). Dynamic assessment has been further elaborated in the work of Ann Brown , and John D. Bransford and in theories of multiple intelligences authored by Howard Gardner and Robert Sternberg . J.P. Guilford 's Structure of Intellect (1967) model of intelligence used three dimensions, which, when combined, yielded

3612-520: The basic battery has 2 subtests for each scale (8 in total). It takes an hour to administer the standard battery and 40 minutes for the basic battery (Naglieri & Das, 1997). The CAS battery provides a standard score for each process as well as a Full Scale standard score. The average internal reliability coefficients across ages 15–17 for the PASS scales are: Each of these scales are described in detail below. For further explanation, see Naglieri, 1999 (B), Naglieri & Das (2005). Additional details on

3696-450: The child is asked to repeat the sentence exactly as presented. The sentence questions subtest uses the same type of sentences that are used in the sentence repetition subtest. However, now the child is read a sentence and asked a question about it. For example, the examiner reads "The blue yellows the green" and asks the child "Who yellows the green?" In a modified form, it has been used as a test of working memory. Speech Rate (Ages 5 to 7)

3780-448: The child's zone of proximal development. Combination of the two indexes—the level of actual and the zone of the proximal development—according to Vygotsky, provides a significantly more informative indicator of psychological development than the assessment of the level of actual development alone. His ideas on the zone of development were later developed in a number of psychological and educational theories and practices, most notably under

3864-686: The current versions of the Stanford–Binet Intelligence Scales , Woodcock–Johnson Tests of Cognitive Abilities , the Kaufman Assessment Battery for Children , the Cognitive Assessment System , and the Differential Ability Scales . There are various other IQ tests, including: IQ scales are ordinally scaled . The raw score of the norming sample is usually (rank order) transformed to

3948-470: The early 20th century, a phenomenon called the Flynn effect . Investigation of different patterns of increases in subtest scores can also inform current research on human intelligence. Historically, many proponents of IQ testing have been eugenicists who used pseudoscience to push now-debunked views of racial hierarchy in order to justify segregation and oppose immigration . Such views are now rejected by

4032-407: The early adulthood) while longitudinal data mostly show that intelligence is stable until mid-adulthood or later. Subsequently, intelligence seems to decline slowly. For decades, practitioners' handbooks and textbooks on IQ testing have reported IQ declines with age after the beginning of adulthood. However, later researchers pointed out this phenomenon is related to the Flynn effect and is in part

4116-400: The effects of aging. The theory was almost forgotten, but was revived by his student John L. Horn (1966) who later argued Gf and Gc were only two among several factors, and who eventually identified nine or ten broad abilities. The theory continued to be called Gf-Gc theory. John B. Carroll (1993), after a comprehensive reanalysis of earlier data, proposed the three stratum theory , which

4200-565: The end, two hundred thousand officers presided, and two- thirds of them had started their careers in training camps where the tests were applied. In some camps, no man scoring below C could be considered for officer training. In total 1.75 million men were tested, making the results the first mass-produced written tests of intelligence, though considered dubious and non-usable, for reasons including high variability of test implementation throughout different camps and questions testing for familiarity with American culture rather than intelligence. After

4284-416: The estimate. For modern tests, the confidence interval can be approximately 10 points and reported standard error of measurement can be as low as about three points. Reported standard error may be an underestimate, as it does not account for all sources of error. Outside influences such as low motivation or high anxiety can occasionally lower a person's IQ test score. For individuals with very low scores,

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4368-411: The fallacy of reification , "our tendency to convert abstract concepts into entities". Gould's argument sparked a great deal of debate, and the book is listed as one of Discover Magazine ' s "25 Greatest Science Books of All Time". Along these same lines, critics such as Keith Stanovich do not dispute the capacity of IQ test scores to predict some kinds of achievement, but argue that basing

4452-422: The first formal factor analysis of correlations between the tests. He observed that children's school grades across seemingly unrelated school subjects were positively correlated, and reasoned that these correlations reflected the influence of an underlying general mental ability that entered into performance on all kinds of mental tests. He suggested that all mental performance could be conceptualized in terms of

4536-427: The first mental testing center in the world in 1882 and he published "Inquiries into Human Faculty and Its Development" in 1883, in which he set out his theories. After gathering data on a variety of physical variables, he was unable to show any such correlation, and he eventually abandoned this research. French psychologist Alfred Binet and psychiatrist Théodore Simon , had more success in 1905, when they published

4620-637: The first task, targets are letters that are physically the same (e.g., BB but not Bb). For the second task, targets are letters that have the same name (e.g., Bb but not Ab). This subtest is an adaptation of Posner & Boise (1971). Simultaneous processing is essential for organization of information into groups or a coherent whole. It requires both nonverbal and verbal processing for the analyses and synthesis of logical and grammatical components of language and comprehension of word relationships. The Simultaneous scale has nonverbal matrices, verbal spatial relations, and figure memory. Nonverbal matrices items present

4704-399: The four separate scores, evidence of strategy use and theoretical interpretation of the subtests. Keith and Kranzler (1999) challenged this position and argued that there was insufficient support. Naglieri (1999 B) and Puhan, Das & Naglieri (2005) responded with reasonable evidence and rational arguments in defense of the structure of the test and the validity of the 4-factor CAS. However,

4788-520: The human race to improve in its overall quality, therefore allowing for humans to direct their own evolution. Henry H. Goddard was a eugenicist. In 1908, he published his own version, The Binet and Simon Test of Intellectual Capacity , and cordially promoted the test. He quickly extended the use of the scale to the public schools (1913), to immigration ( Ellis Island , 1914) and to a court of law (1914). Unlike Galton, who promoted eugenics through selective breeding for positive traits, Goddard went with

4872-403: The idea that IQ heritability rises with age. Researchers building on this phenomenon dubbed it "The Wilson Effect," named after the behavioral geneticist. A paper by Thomas J. Bouchard Jr. , examining twin and adoption studies, including twins "reared apart," finds that IQ "reaches an asymptote at about 0.80 at 18–20 years of age and continuing at that level well into adulthood. In the aggregate,

4956-622: The issue has not yet been resolved as yet. Insofar as constructive criticism goes, supplementary tests are necessary for extending the application of CAS. To begin with existing tests, the Successive subtests should have a nonverbal measure, such as Luria's test that asks participants to continue a series "+++__ __+++__ __+++__ __......", or a motor response of tapping to dot sequences such as "... .. ... .. ... ... .. " as given in Das, Kirby & Jarman (1979). Similarly, Attention subtests should include both

5040-498: The kind of intelligence necessary to do well in academic work. But if the purpose is to assess intelligence in a broader sense, the validity of IQ tests is questionable." Some scientists have disputed the value of IQ as a measure of intelligence altogether. In The Mismeasure of Man (1981, expanded edition 1996), evolutionary biologist Stephen Jay Gould compared IQ testing with the now-discredited practice of determining intelligence via craniometry , arguing that both are based on

5124-402: The late 20th century. The phenomenon has been termed the negative Flynn effect . A study of Norwegian military conscripts' test records found that IQ scores have been falling for generations born after the year 1975, and that the underlying cause of both initial increasing and subsequent falling trends appears to be environmental rather than genetic. Ronald S. Wilson is largely credited with

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5208-419: The matching numbers subtest, children are presented with four pages containing eight rows of numbers. The child is instructed to underline the two numbers that are the same. The planned codes subtest contains two pages, each with a distinct set of codes arranged in seven rows and eight columns. At the top of each page is a legend that indicates how letters relate to simple codes (e.g., A = OX; B = XX; C = OO). In

5292-414: The mean scores of tests at ages 11, 12, and 13. The current consensus is that fluid intelligence generally declines with age after early adulthood, while crystallized intelligence remains intact. However, the exact peak age of fluid intelligence or crystallized intelligence remains elusive. Cross-sectional studies usually show that especially fluid intelligence peaks at a relatively young age (often in

5376-445: The measurement consistency of a test. A reliable test produces similar scores upon repetition. On aggregate, IQ tests exhibit high reliability, although test-takers may have varying scores when taking the same test on differing occasions, and may have varying scores when taking different IQ tests at the same age. Like all statistical quantities, any particular estimate of IQ has an associated standard error that measures uncertainty about

5460-450: The origin of each of the 12 tests in CAS have been discussed at some length in Das, Naglieri &Kirby (1994) and more recently in a review by McCrea (2009). Planning helps us select or develop strategies needed to complete tasks for which a solution is needed, and is critical to all activities where an individual has to determine how to solve a problem The Planning scale includes matching numbers, planned codes, and planned connections. In

5544-472: The planned connections (a variation of Trails test) subtest the child is instructed to connect numbers in sequence that appear in a quasi-random order (e.g., 1–2–3, etc.). For these two tests, the child connects numbers and letters in sequential order, alternating between numbers and letters (e.g., 1-A-2-B, etc.). All Planning subtests include strategy assessment. This is conducted after the administration of each subtest and recorded in two categories: Attention

5628-775: The posterior region of the cortex. It has influenced some recent IQ tests, and been seen as a complement to the Cattell–Horn–Carroll theory described above. There are a variety of individually administered IQ tests in use in the English-speaking world. The most commonly used individual IQ test series is the Wechsler Adult Intelligence Scale (WAIS) for adults and the Wechsler Intelligence Scale for Children (WISC) for school-age test-takers. Other commonly used individual IQ tests (some of which do not label their standard scores as "IQ" scores) include

5712-451: The predicament test (Channon, 2004). IQ test An intelligence quotient ( IQ ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence . Originally, IQ was a score obtained by dividing a person's mental age score, obtained by administering an intelligence test, by the person's chronological age, both expressed in terms of years and months. The resulting fraction ( quotient )

5796-600: The relationship between the CAS and achievement has shown that the PASS processes strongly predict academic achievement in spite of the fact that it does not include vocabulary (Naglieri and Rojahn, 2004). Similarly, CAS tests have been used for understanding, assessment of and intervention with educational problems associated with reading disabilities (Das, 2009 ) such as autism, attention-deficit-hyperactivity disorder (Naglieri, 2005). CAS tests have also been used for clinical evaluation of intellectual disability and cognitive changes in ageing (Das, 2003). Deserving of special mention

5880-593: The same questions. Such bias can be a result of culture, educational level and other factors that are independent of group traits. DIF is only considered if test-takers from different groups with the same underlying latent ability level have a different chance of giving specific responses. Such questions are usually removed in order to make the test equally fair for both groups. Common techniques for analyzing DIF are item response theory (IRT) based methods, Mantel-Haenszel, and logistic regression . A 2005 study found that "differential validity in prediction suggests that

5964-562: The significance of heritability estimates and the mechanisms of inheritance. IQ scores are used for educational placement, assessment of intellectual ability , and evaluating job applicants. In research contexts, they have been studied as predictors of job performance and income . They are also used to study distributions of psychometric intelligence in populations and the correlations between it and other variables. Raw scores on IQ tests for many populations have been rising at an average rate that scales to three IQ points per decade since

6048-431: The six drawings that best answers the question. In Figure memory, a combination of Figure-Copying and Memory for Designs, the child is presented a two- or three-dimensional geometric figure for 5 seconds and then presented immediately with a response page, on which the original geometric figure is embedded in a larger, more complex geometric pattern. The child is asked to identify the original design. Successive processing

6132-430: The studies also confirm that shared environmental influence decreases across age, approximating about 0.10 at 18–20 years of age and continuing at that level into adulthood." IQ can change to some degree over the course of childhood. In one longitudinal study , the mean IQ scores of tests at ages 17 and 18 were correlated at r = 0.86 with the mean scores of tests at ages five, six, and seven and at r = 0.96 with

6216-426: The study of human diversity and the study of inheritance of human traits, he believed that intelligence was largely a product of heredity (by which he did not mean genes , although he did develop several pre-Mendelian theories of particulate inheritance). He hypothesized that there should exist a correlation between intelligence and other observable traits such as reflexes , muscle grip, and head size . He set up

6300-580: The subsequent need to study it using qualitative, as opposed to quantitative, measures (White, 2000). American psychologist Henry H. Goddard published a translation of it in 1910. American psychologist Lewis Terman at Stanford University revised the Binet–Simon scale, which resulted in the Stanford revision of the Binet-Simon Intelligence Scale (1916). It became the most popular test in the United States for decades. The abbreviation "IQ"

6384-474: The test measures what it purports to measure. While IQ tests are generally considered to measure some forms of intelligence, they may fail to serve as an accurate measure of broader definitions of human intelligence inclusive of, for example, creativity and social intelligence . For this reason, psychologist Wayne Weiten argues that their construct validity must be carefully qualified, and not be overstated. According to Weiten, "IQ tests are valid measures of

6468-422: The testing room and classification by IQ testing depend on the definition of "intelligence" used in a particular case and on the reliability and error of estimation in the classification procedure. The English statistician Francis Galton (1822–1911) made the first attempt at creating a standardized test for rating a person's intelligence. A pioneer of psychometrics and the application of statistical methods to

6552-490: The war, positive publicity promoted by army psychologists helped to make psychology a respected field. Subsequently, there was an increase in jobs and funding in psychology in the United States. Group intelligence tests were developed and became widely used in schools and industry. The results of these tests, which at the time reaffirmed contemporary racism and nationalism, are considered controversial and dubious, having rested on certain contested assumptions: that intelligence

6636-575: Was coined by the psychologist William Stern for the German term Intelligenzquotient , his term for a scoring method for intelligence tests at University of Breslau he advocated in a 1912 book. The many different kinds of IQ tests include a wide variety of item content. Some test items are visual, while many are verbal. Test items vary from being based on abstract-reasoning problems to concentrating on arithmetic, vocabulary, or general knowledge. The British psychologist Charles Spearman in 1904 made

6720-570: Was earlier often subdivided into only Gf and Gc, which were thought to correspond to the nonverbal or performance subtests and verbal subtests in earlier versions of the popular Wechsler IQ test. More recent research has shown the situation to be more complex. Modern comprehensive IQ tests do not stop at reporting a single IQ score. Although they still give an overall score, they now also give scores for many of these more restricted abilities, identifying particular strengths and weaknesses of an individual. An alternative to standard IQ tests, meant to test

6804-501: Was heritable, innate, and could be relegated to a single number, the tests were enacted systematically, and test questions actually tested for innate intelligence rather than subsuming environmental factors. The tests also allowed for the bolstering of jingoist narratives in the context of increased immigration, which may have influenced the passing of the Immigration Restriction Act of 1924 . L.L. Thurstone argued for

6888-480: Was later extended to poor people. Goddard's intelligence test was endorsed by the eugenicists to push for laws for forced sterilization. Different states adopted the sterilization laws at different paces. These laws, whose constitutionality was upheld by the Supreme Court in their 1927 ruling Buck v. Bell , forced over 60,000 people to go through sterilization in the United States. California's sterilization program

6972-469: Was multiplied by 100 to obtain the IQ score. For modern IQ tests , the raw score is transformed to a normal distribution with mean 100 and standard deviation 15. This results in approximately two-thirds of the population scoring between IQ 85 and IQ 115 and about 2 percent each above 130 and below 70 . Scores from intelligence tests are estimates of intelligence. Unlike, for example, distance and mass,

7056-468: Was so effective that the Nazis turned to the government for advice on how to prevent the birth of the "unfit". While the US eugenics movement lost much of its momentum in the 1940s in view of the horrors of Nazi Germany, advocates of eugenics (including Nazi geneticist Otmar Freiherr von Verschuer ) continued to work and promote their ideas in the United States. In later decades, some eugenic principles have made

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