The following outline is provided as an overview of and topical guide to human intelligence:
Human intelligence is, in the human species, the mental capacities to learn, understand, and reason, including the capacities to comprehend ideas, plan, solve problems, and use language to communicate.
Scholarly journals and societies
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 were 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.
Human intelligence is the intellectual capability of humans, which is marked by complex cognitive feats and high levels of motivation and self-awareness. Using their intelligence, humans are able to learn, form concepts, understand, and apply logic and reason. Human intelligence is also thought to encompass their capacities to recognize patterns, plan, innovate, solve problems, make decisions, retain information, and use language to communicate.
The Stanford–Binet Intelligence Scales is an individually administered intelligence test that was revised from the original Binet–Simon Scale by Alfred Binet and Théodore Simon. It is in its fifth edition (SB5), which was released in 2003.
The g factor is a construct developed in psychometric investigations of cognitive abilities and human intelligence. It is a variable that summarizes positive correlations among different cognitive tasks, reflecting the fact that an individual's performance on one type of cognitive task tends to be comparable to that person's performance on other kinds of cognitive tasks. The g factor typically accounts for 40 to 50 percent of the between-individual performance differences on a given cognitive test, and composite scores based on many tests are frequently regarded as estimates of individuals' standing on the g factor. The terms IQ, general intelligence, general cognitive ability, general mental ability, and simply intelligence are often used interchangeably to refer to this common core shared by cognitive tests. However, the g factor itself is a mathematical construct indicating the level of observed correlation between cognitive tasks. The measured value of this construct depends on the cognitive tasks that are used, and little is known about the underlying causes of the observed correlations.
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 includes 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.
David "Weshy" Wechsler was a Romanian-American psychologist. He developed well-known intelligence scales, such as the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC) to get to know his patients at Bellevue Hospital. A Review of General Psychology survey, published in 2002, ranked Wechsler as the 51st most cited psychologist of the 20th century.
Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as the ability to perceive or infer information; and to retain it as knowledge to be applied to adaptive behaviors within an environment or context.
The Wechsler Adult Intelligence Scale (WAIS) is an IQ test designed to measure intelligence and cognitive ability in adults and older adolescents.
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 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.
The Kaufman Assessment Battery for Children (KABC) is a clinical instrument for assessing cognitive development. Its construction incorporates several recent developments in both psychological theory and statistical methodology. The test was developed by Alan S. Kaufman and Nadeen L. Kaufman in 1983 and revised in 2004. The test has been translated and adopted for many countries, such as the Japanese version of the K-ABC by the Japanese psychologists Tatsuya Matsubara, Kazuhiro Fujita, Hisao Maekawa, and Toshinori Ishikuma.
The Culture Fair Intelligence Test (CFIT) was created by Raymond Cattell in 1949 as an attempt to measure cognitive abilities devoid of sociocultural and environmental influences. Scholars have subsequently concluded that the attempt to construct measures of cognitive abilities devoid of the influences of experiential and cultural conditioning is a challenging one. Cattell proposed that general intelligence (g) comprises both fluid intelligence (Gf) and crystallized intelligence (Gc). Whereas Gf is biologically and constitutionally based, Gc is the actual level of a person's cognitive functioning, based on the augmentation of Gf through sociocultural and experiential learning.
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 Cattell–Horn–Carroll theory, is a psychological theory on the structure of human cognitive abilities. Based on the work of three psychologists, Raymond B. Cattell, John L. Horn and John B. Carroll, the Cattell–Horn–Carroll theory is regarded as an important theory in the study of human intelligence. Based on a large body of research, spanning over 70 years, Carroll's Three Stratum theory was developed using the psychometric approach, the objective measurement of individual differences in abilities, and the application of factor analysis, a statistical technique which uncovers relationships between variables and the underlying structure of concepts such as 'intelligence'. The psychometric approach has consistently facilitated the development of reliable and valid measurement tools and continues to dominate the field of intelligence research.
IQ classification is the practice of categorizing human intelligence, as measured by intelligence quotient (IQ) tests, into categories such as "superior" or "average".
The Cognitive Abilities Test (CogAT) is a group-administered K–12 assessment published by Riverside Insights and intended to estimate students' learned reasoning and problem solving abilities through a battery of verbal, quantitative, and nonverbal test items. The test purports to assess students' acquired reasoning abilities while also predicting achievement scores when administered with the co-normed Iowa Tests. The test was originally published in 1954 as the Lorge-Thorndike Intelligence Test, after the psychologists who authored the first version of it, Irving Lorge and Robert L. Thorndike. The CogAT is one of several tests used in the United States to help teachers or other school staff make student placement decisions for gifted education programs, and is accepted for admission to Intertel, a high IQ society for those who score at or above the 99th percentile on a test of intelligence.
The Woodcock–Johnson Tests of Cognitive Abilities is a set of intelligence tests first developed in 1977 by Richard Woodcock and Mary E. Bonner Johnson. It was revised in 1989, again in 2001, and most recently in 2014; this last version is commonly referred to as the WJ IV. They may be administered to children from age two right up to the oldest adults. The previous edition WJ III was praised for covering "a wide variety of cognitive skills".
The history of the race and intelligence controversy concerns the historical development of a debate about possible explanations of group differences encountered in the study of race and intelligence. Since the beginning of IQ testing around the time of World War I, there have been observed differences between the average scores of different population groups, and there have been debates over whether this is mainly due to environmental and cultural factors, or mainly due to some as yet undiscovered genetic factor, or whether such a dichotomy between environmental and genetic factors is the appropriate framing of the debate. Today, the scientific consensus is that genetics does not explain differences in IQ test performance between racial groups.