The factors that have been of greatest interest to scholars include prenatal development, nutritionbirth order, home and family environment, and the effects of schooling. Birth order Surprisingly, statistical data shows that birth order can somewhat affect IQ: Each successive child born into a family has, on average, a slightly lower IQ, by about.
Scientific racism Alfred Binet —inventor of the first intelligence test. Claims of races having different intelligence were used to justify colonialismslaveryracismsocial Darwinismand racial eugenics.
Racial thinkers such as Arthur de Gobineau relied crucially on the assumption that black people were innately inferior to whites in developing their ideologies of white supremacy. Even enlightenment thinkers such as Thomas Jeffersona slave owner, believed blacks to be innately inferior to whites in physique and intellect.
Binet warned that results from his test should not be assumed to measure innate intelligence or used to label individuals permanently. As Terman's test was published, there was great concern in the United States about the abilities and skills of recent immigrants.
Different immigrant nationalities were sometimes thought to belong to different races, such as Slavs. A different set of tests developed by Robert Yerkes were used to evaluate draftees for World War I, and researchers found that people from southern and eastern Europe scored lower than native-born Americans, that Americans from northern states had higher scores than Americans from southern states, and that Black Americans scored lower than white Americans.
In his influential work A Study of American Intelligence psychologist Carl Brigham used the results of the Army tests to argue for a stricter immigration policy, limiting immigration to countries considered to belong to the "nordic race".
On the other hand, many scientists reacted to eugenicist claims linking abilities and moral character to racial or genetic ancestry. They pointed to the contribution of environment to test results such as speaking English as a second language. Discussion of the issue in the United States also influenced German Nazi claims of the "nordics" being a " master race ", influenced by Grant's writings.
Jensenism As the de-segregation of the American South was begun in the s the debate about black intelligence resurfaced. Audrey Shueyfunded by Draper's Pioneer Fundpublished a new analysis of Yerkes' tests, concluding that blacks really were of inferior intellect to whites.
This study was used by segregationists as an argument that it was to the advantage of black children to be educated separately from the superior white children. The Bell Curve debate Another revival of public debate followed the appearance of The Bell Curvea book by Richard Herrnstein and Charles Murraywho strongly emphasized the societal effects of low IQ focusing in most chapters strictly on the non-Hispanic white population of the United States.
Knowns and Unknowns ", acknowledging a difference between mean IQ scores of whites and blacks as well as the absence of any adequate explanation of it, either environmental or genetic. The Bell Curve prompted the publication of several multiple-author books responding from a variety of points of view.
The Science of Mental Ability was published a few years later in Why Schools and Cultures Count Intelligence quotient and Intelligence The concept of intelligence and the degree to which intelligence is measurable is a matter of debate. While there is some consensus about how to define intelligence, it is not universally accepted that it is something that can be unequivocally measured by a single figure.
Arthur Jensen was a proponent of the view that there is a correlation between scores on all the known types of IQ tests and that this correlation points to an underlying factor of general intelligenceor g.
In most conceptions of g it is considered to be fairly fixed in a given individual and unresponsive to training or other environmental influences. In this view test score differences, especially in those tasks considered to be particularly "g-loaded" reflect the test takers innate capability.
Other psychometricians argue that, while there may or may not be a general intelligence factor, performance on tests rely crucially on knowledge acquired through prior exposure to the types of tasks that such tests contain. This view would mean that tests cannot be expected to reflect only the innate abilities of a given individual, because the expression of potential will always be mediated by experience and cognitive habits.
It also means that comparison of test scores from persons with widely different life experiences and cognitive habits is not an expression of their relative innate potentials. Race classification of humans and Race and genetics The majority of anthropologists today consider race to be a sociopolitical phenomenon rather than a biological one,  a view supported by considerable genetics research.
It derives from people's desire to classify. The official position of the AAA, adopted inis that advances in scientific knowledge have made it "clear that human populations are not unambiguous, clearly demarcated, biologically distinct groups" and that "any attempt to establish lines of division among biological populations [is] both arbitrary and subjective.
With current methods of genetic analysis it is possible to determine the composition of genetic ancestry of an individual with significant precision. This is because different genes occur with different frequencies in different geographically defined populations, and by correlating a large amount of genes through cluster analysis it is probable to determine with high likelihood the geographic origins of an individual through DNA.
This suggests to some that the classical socially defined genetic categories really have a biological basis, in the sense that racial categorization is a visual estimate of a person's continental ancestry based on their phenotype—which correlates with genotypical ancestry as determined by DNA tests.
Race in studies of human intelligence is almost always determined using self-reports, rather than based on analyses of the genetic characteristics of the tested individuals. According to psychologist David Rowe, self-report is the preferred method for racial classification in studies of racial differences because classification based on genetic markers alone ignore the "cultural, behavioral, sociological, psychological, and epidemiological variables" that distinguish racial groups.
Loring Brace  and geneticist Joseph Graves disagree with the idea that cluster analysis and the correlation between self-reported race and genetic ancestry support biological race. The cluster structure of the genetic data is dependent on the initial hypotheses of the researcher and the populations sampled.
When one samples continental groups, the clusters become continental; if one had chosen other sampling patterns, the clusters would be different. Kaplan therefore concludes that, while differences in particular allele frequencies can be used to identify populations that loosely correspond to the racial categories common in Western social discourse, the differences are of no more biological significance than the differences found between any human populations e.
Hunt agrees that racial categories are defined by social conventions, though he points out that they also correlate with clusters of both genetic traits and cultural traits.What transient factors affect performance on IQ tests? – Dean May 4 '16 at add a comment | 2 Answers quote studies (I can look up the references if you like).
There are indeed a lot of factors that can influence ones score on an IQ test. These are some transient factors that came to my mind: The setting: was the test taken at.
Environmental factors include differences in the way young people are educated, increases in time spent online, changes in nutrition and less reading overall.
The downward trend is a reversal of the Flynn effect, a term that describes the vast improvement of IQ scores in many parts of the world throughout the 20th century. The manual also says, "IQ scores in autism spectrum disorder may be unstable, particularly in early childhood." 2 In other words, a U.S.
study found that almost half of the children with ASD had average or above average intelligence, that is, an IQ score above To further examine the role of motivation on both IQ test scores and the ability of IQ tests to predict life success, Duckworth and her team carried out two studies, both reported in today's paper.
Scores on most types of RT tasks tend to correlate with scores on standard IQ tests as well as with g, and no relationship has been found between RT and any other psychometric factors independent of g.
The children of low socioeconomic status score approximately 10 to 15 IQ points below the middle-class and higher-class children (Hall and Kaye, ). These differences are present by the first grade and are sustained throughout the school years.