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.
Nature versus nurture is a long-standing debate in biology and society about the relative influence on human beings of their genetic inheritance (nature) and the environmental conditions of their development (nurture). The alliterative expression "nature and nurture" in English has been in use since at least the Elizabethan period and goes back to medieval French. The complementary combination of the two concepts is an ancient concept. Nature is what people think of as pre-wiring and is influenced by genetic inheritance and other biological factors. Nurture is generally taken as the influence of external factors after conception e.g. the product of exposure, experience and learning on an individual.
Twin studies are studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders. Twin research is considered a key tool in behavioral genetics and in related fields, from biology to psychology. Twin studies are part of the broader methodology used in behavior genetics, which uses all data that are genetically informative – siblings studies, adoption studies, pedigree, etc. These studies have been used to track traits ranging from personal behavior to the presentation of severe mental illnesses such as schizophrenia.
Achievement gaps in the United States are observed, persistent disparities in measures of educational performance among subgroups of U.S. students, especially groups defined by socioeconomic status (SES), race/ethnicity and gender. The achievement gap can be observed through a variety of measures, including standardized test scores, grade point average, dropout rates, college enrollment, and college completion rates. The gap in achievement between lower income students and higher income students exists in all nations and it has been studied extensively in the U.S. and other countries, including the U.K. Various other gaps between groups exist around the globe as well.
The Programme for International Student Assessment (PISA) is a worldwide study by the Organisation for Economic Co-operation and Development (OECD) in member and non-member nations intended to evaluate educational systems by measuring 15-year-old school pupils' scholastic performance on mathematics, science, and reading. It was first performed in 2000 and then repeated every three years. Its aim is to provide comparable data with a view to enabling countries to improve their education policies and outcomes. It measures problem solving and cognition.
Hereditarianism is the doctrine or school of thought that heredity plays a significant role in determining human nature and character traits, such as intelligence and personality. Hereditarians believe in the power of genetics to explain human character traits and solve human social and political problems. Hereditarians adopt the view that an understanding of human evolution can extend the understanding of human nature.
A large body of research indicates that IQ and similar measures vary between individuals and between certain groups, and that they correlate with socially important outcomes such as educational achievement, employment, crime, poverty and socioeconomic status.
Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. A norm of reaction is a graph that shows the relationship between genes and environmental factors when phenotypic differences are continuous. They can help illustrate GxE interactions. When the norm of reaction is not parallel, as shown in the figure below, there is a gene by environment interaction. This indicates that each genotype responds to environmental variation in a different way. Environmental variation can be physical, chemical, biological, behavior patterns or life events.
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.
Intelligence: Knowns and Unknowns is a report about scientific findings on human intelligence, issued in 1995 by a task force created by the Board of Scientific Affairs of the American Psychological Association (APA) following the publication of The Bell Curve and the scholarly debate that followed it. The report was subsequently published in the February 1996 issue of the peer-reviewed journal American Psychologist.
The study of height and intelligence examines correlations between human height and human intelligence. Some epidemiological research on the subject has shown that there is a small but statistically significant positive correlation between height and intelligence after controlling for socioeconomic class and parental education. The cited study, however, does not draw any conclusions about height and intelligence, but rather suggests "a continuing effect of post-natal growth on childhood cognition beyond the age of 9 years." This correlation arises in both the developed and developing world and persists across age groups. An individual's taller stature has been attributed to higher economic status, which often translates to a higher quality of nutrition. This correlation, however, can be inverted to characterize one's socioeconomic status as a consequence of stature, where shorter stature can attract discrimination that affects many factors, among them employment, and treatment by educators. One such theory argues that since height strongly correlates with white and gray matter volume, it may act as a biomarker for cerebral development which itself mediates intelligence. Competing explanations include that certain genetic factors may influence both height and intelligence, or that both height and intelligence may be affected in similar ways by adverse environmental exposures during development. Measurements of the total surface area and mean thickness of the cortical grey matter using a magnetic resonance imaging (MRI) revealed that the height of individuals had a positive correlation with the total cortical surface area. This supports the idea that genes that influence height also influence total surface area of the brain, which in turn influences intelligence, resulting in the correlation. Other explanations further qualify the positive correlation between height and intelligence, suggesting that because the correlation becomes weaker with higher socioeconomic class and education level, environmental factors could partially override any genetic factors affecting both characteristics.
Eric Alan Hanushek is an economist who has written prolifically on public policy with a special emphasis on the economics of education. Since 2000, he has been a Paul and Jean Hanna Senior Fellow at the Hoover Institution, an American public policy think tank located at Stanford University in California. He was awarded the Yidan Prize for Education Research in 2021.
Genes, Brain and Behavior is a peer-reviewed scientific journal covering research in the fields of behavioral, neural, and psychiatric genetics. It is published by Wiley-Blackwell on behalf of the International Behavioural and Neural Genetics Society. The journal was established in 2002 as a quarterly and is currently published monthly. G2B is a hybrid open access journal, but two years after publication all content is available for free online.
Sex differences in education are a type of sex discrimination in the education system affecting both men and women during and after their educational experiences. Men are more likely to be literate on a global average, although higher literacy scores for women are prevalent in many countries. Women are more likely to achieve a tertiary education degree compared to men of the same age. Men tended to receive more education than women in the past, but the gender gap in education has reversed in recent decades in most Western countries and many non-Western countries.
Behavioural genetics, also referred to as behaviour genetics, is a field of scientific research that uses genetic methods to investigate the nature and origins of individual differences in behaviour. While the name "behavioural genetics" connotes a focus on genetic influences, the field broadly investigates the extent to which genetic and environmental factors influence individual differences, and the development of research designs that can remove the confounding of genes and environment. Behavioural genetics was founded as a scientific discipline by Francis Galton in the late 19th century, only to be discredited through association with eugenics movements before and during World War II. In the latter half of the 20th century, the field saw renewed prominence with research on inheritance of behaviour and mental illness in humans, as well as research on genetically informative model organisms through selective breeding and crosses. In the late 20th and early 21st centuries, technological advances in molecular genetics made it possible to measure and modify the genome directly. This led to major advances in model organism research and in human studies, leading to new scientific discoveries.
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.
Academic achievement or academic performance is the extent to which a student, teacher or institution has attained their short or long-term educational goals. Completion of educational benchmarks such as secondary school diplomas and bachelor's degrees represent academic achievement.
The racial achievement gap in the United States refers to disparities in educational achievement between differing ethnic/racial groups. It manifests itself in a variety of ways: African-American and Hispanic students are more likely to earn lower grades, score lower on standardized tests, drop out of high school, and they are less likely to enter and complete college than whites, while whites score lower than Asian Americans.
The relationship between intelligence and education is one that scientists have been studying for years.
