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The Flynn effect is the substantial and long-sustained increase in both fluid and crystallized intelligence test scores that were measured in many parts of the world over the 20th century, named after researcher James Flynn (1934–2020). When intelligence quotient (IQ) tests are initially standardized using a sample of test-takers, by convention the average of the test results is set to 100 and their standard deviation is set to 15 or 16 IQ points. When IQ tests are revised, they are again standardized using a new sample of test-takers, usually born more recently than the first; the average result is set to 100. When the new test subjects take the older tests, in almost every case their average scores are significantly above 100.
An intelligence quotient (IQ) is a total score derived from a set of standardised tests or subtests designed to assess human intelligence. The abbreviation "IQ" 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.
Discussions of race and intelligence – specifically regarding claims of differences in intelligence along racial lines – have appeared in both popular science and academic research since the modern concept of race was first introduced. With the inception of IQ testing in the early 20th century, differences in average test performance between racial groups have been observed, though these differences have fluctuated and in many cases steadily decreased over time. Complicating the issue, modern science has concluded that race is a socially constructed phenomenon rather than a biological reality, and there exist various conflicting definitions of intelligence. In particular, the validity of IQ testing as a metric for human intelligence is disputed. Today, the scientific consensus is that genetics does not explain differences in IQ test performance between groups, and that observed differences are environmental in origin.
Psychological testing refers to the administration of psychological tests. Psychological tests are administered or scored by trained evaluators. A person's responses are evaluated according to carefully prescribed guidelines. Scores are thought to reflect individual or group differences in the construct the test purports to measure. The science behind psychological testing is psychometrics.
Intellectual giftedness is an intellectual ability significantly higher than average. It is a characteristic of children, variously defined, that motivates differences in school programming. It is thought to persist as a trait into adult life, with various consequences studied in longitudinal studies of giftedness over the last century. These consequences sometimes include stigmatizing and social exclusion. There is no generally agreed definition of giftedness for either children or adults, but most school placement decisions and most longitudinal studies over the course of individual lives have followed people with IQs in the top 2.5 percent of the population—that is, IQs above 130. Definitions of giftedness also vary across cultures.
The Wechsler Adult Intelligence Scale (WAIS) is an IQ test designed to measure intelligence and cognitive ability in adults and older adolescents. For children between the ages of 6 and 16, Wechsler Intelligence Scale for Children (WISC) is commonly used.
Cognitive tests are assessments of the cognitive capabilities of humans and other animals. Tests administered to humans include various forms of IQ tests; those administered to animals include the mirror test and the T maze test. Such testing is used in psychology and psychometrics, as well as other fields studying human and animal intelligence.
The "ceiling effect" is one type of scale attenuation effect; the other scale attenuation effect is the "floor effect". The ceiling effect is observed when an independent variable no longer has an effect on a dependent variable, or the level above which variance in an independent variable is no longer measurable. The specific application varies slightly in differentiating between two areas of use for this term: pharmacological or statistical. An example of use in the first area, a ceiling effect in treatment, is pain relief by some kinds of analgesic drugs, which have no further effect on pain above a particular dosage level. An example of use in the second area, a ceiling effect in data-gathering, is a survey that groups all respondents into income categories, not distinguishing incomes of respondents above the highest level measured in the survey instrument. The maximum income level able to be reported creates a "ceiling" that results in measurement inaccuracy, as the dependent variable range is not inclusive of the true values above that point. The ceiling effect can occur any time a measure involves a set range in which a normal distribution predicts multiple scores at or above the maximum value for the dependent variable.
The Wechsler Intelligence Scale for Children (WISC) is an individually administered intelligence test for children between the ages of 6 and 16. The Fifth Edition is the most recent version.
Research on the heritability of IQ inquires into the degree of variation in IQ within a population that is due to genetic variation between individuals in that population. There has been significant controversy in the academic community about the heritability of IQ since research on the issue began in the late nineteenth century. Intelligence in the normal range is a polygenic trait, meaning that it is influenced by more than one gene, and in the case of intelligence at least 500 genes. Further, explaining the similarity in IQ of closely related persons requires careful study because environmental factors may be correlated with genetic factors.
The Wechsler Preschool and Primary Scale of Intelligence (WPPSI) is an intelligence test designed for children ages 2 years 6 months to 7 years 7 months developed by David Wechsler in 1967. It is a descendant of the earlier Wechsler Adult Intelligence Scale and the Wechsler Intelligence Scale for Children tests. Since its original publication the WPPSI has been revised three times in 1989, 2002, and 2012. The latest version, WPPSI–IV, published by Pearson Education, is a revision of the WPPSI-R and the WPPSI-III. It provides subtest and composite scores that represent intellectual functioning in verbal and performance cognitive domains, as well as providing a composite score that represents a child's general intellectual ability.
Mental age is a concept related to intelligence. It looks at how a specific individual, at a specific age, performs intellectually, compared to average intellectual performance for that individual's actual chronological age (i.e. time elapsed since birth). The intellectual performance is based on performance in tests and live assessments by a psychologist. The score achieved by the individual is compared to the median average scores at various ages, and the mental age (x, say) is derived such that the individual's score equates to the average score at age x.
The Draw-a-Person test, Draw-A-Man test (DAM), or Goodenough–Harris Draw-a-Person test is a type of test in the domain of psychology. It is both a personality test, specifically projective test, and a cognitive test like IQ. The test subject uses simple art supplies to produce depictions of people. It is used to evaluate children and adolescents for a variety of purposes.
Health can affect intelligence in various ways. Conversely, intelligence can affect health. Health effects on intelligence have been described as being among the most important factors in the origins of human group differences in IQ test scores and other measures of cognitive ability. Several factors can lead to significant cognitive impairment, particularly if they occur during pregnancy and childhood when the brain is growing and the blood–brain barrier of the child is less effective. Such impairment may sometimes be permanent, sometimes be partially or wholly compensated for by later growth.
Environment and intelligence research investigates the impact of environment on intelligence. This is one of the most important factors in understanding human group differences in IQ test scores and other measures of cognitive ability. It is estimated that genes contribute about 20–40% of the variance in intelligence in childhood and about 80% in adulthood. Thus the environment and its interaction with genes account for a high proportion of the variation in intelligence seen in groups of young children, and for a small proportion of the variation observed in groups of mature adults. Historically, there has been great interest in the field of intelligence research to determine environmental influences on the development of cognitive functioning, in particular, fluid intelligence, as defined by its stabilization at 16 years of age. Despite the fact that intelligence stabilizes in early adulthood it is thought that genetic factors come to play more of a role in our intelligence during middle and old age and that the importance of the environment dissipates.
IQ classification is the practice of categorizing human intelligence, as measured by intelligence quotient (IQ) tests, into categories such as "superior" and "average".
Intellectual disability (ID), also known as general learning disability and formerly mental retardation, is a generalized neurodevelopmental disorder characterized by significant impairment in intellectual and adaptive functioning that is first apparent during childhood. Children with intellectual disabilities typically have an intelligence quotient (IQ) below 70 and deficits in at least two adaptive behaviors that affect everyday, general living. According to the DSM-5, intellectual functions include reasoning, problem solving, planning, abstract thinking, judgment, academic learning, and learning from experience. Deficits in these functions must be confirmed by clinical evaluation and individualized standard IQ testing. On the other hand, adaptive behaviors include the social, developmental, and practical skills people learn to perform tasks in their everyday lives. Deficits in adaptive functioning often compromises an individual's independence and ability to meet their social responsibility.
Cognitive epidemiology is a field of research that examines the associations between intelligence test scores and health, more specifically morbidity and mortality. Typically, test scores are obtained at an early age, and compared to later morbidity and mortality. In addition to exploring and establishing these associations, cognitive epidemiology seeks to understand causal relationships between intelligence and health outcomes. Researchers in the field argue that intelligence measured at an early age is an important predictor of later health and mortality differences.
The following outline is provided as an overview of and topical guide to human intelligence:
The Wide Range Intelligence test (WRIT) is an assessment of verbal (crystallized) and visual (fluid) IQ. Running at approximately 30 minutes, the WRIT is shorter than traditional IQ tests. The test also involves only four subtests and requires fewer physical materials than a typical test. It was created alongside the Wide Range Achievement Test 3 (WRAT3), a measure of reading comprehension and academic ability, by Pearson Education in 2000. The WRIT is intended to assess those aged 4 through 85. It is designed for easy administration among trained psychologists, which is accomplished using a hierarchical model that frequently occurs in psychological testing.
References
- ↑ Lim, Christopher R.; Harris, Kristina; Dawson, Jill; Beard, David J.; Fitzpatrick, Ray; Price, Andrew J. (2015-07-01). "Floor and ceiling effects in the OHS: an analysis of the NHS PROMs data set". BMJ Open. 5 (7): e007765. doi:10.1136/bmjopen-2015-007765. ISSN 2044-6055. PMC 4521553 . PMID 26216152.
- ↑ Stephanie (2017-09-10). "Floor Effect / Basement Effect: Definition". Statistics How To. Retrieved 2020-04-14.
- ↑ "Scale Attenuation Effect - SAGE Research Methods". methods.sagepub.com. Retrieved 2020-10-22.
- ↑ Zhu, Leina; Gonzalez, Jorge (2017). "Modeling Floor Effects in Standardized Vocabulary Test Scores in a Sample of Low SES Hispanic Preschool Children under the Multilevel Structural Equation Modeling Framework". Frontiers in Psychology. 8: 2146. doi: 10.3389/fpsyg.2017.02146 . ISSN 1664-1078. PMC 5732956 . PMID 29312033.
- ↑ Sansone, Stephanie M; Schneider, Andrea; Bickel, Erika; Berry-Kravis, Elizabeth; Prescott, Christina; Hessl, David (2014). "Improving IQ measurement in intellectual disabilities using true deviation from population norms". Journal of Neurodevelopmental Disorders. 6 (1): 16. doi: 10.1186/1866-1955-6-16 . ISSN 1866-1947. PMC 4613563 . PMID 26491488.
- ↑ "IQ testing in individuals with intellectual disability". health.ucdavis.edu. Retrieved 2020-04-14.