<P> In 1916 George O. Ferguson conducted research in his Columbia Ph. D. thesis on "The psychology of the Negro", finding them poor in abstract thought, but good in physical responses, recommending how this should be reflected in education . In the same year Lewis Terman, in the manual accompanying the Stanford - Binet Intelligence Test, referred to the higher frequency of morons among non-white American racial groups stating that further research into race difference on intelligence should be conducted and that the "enormously significant racial differences in general intelligence" could not be remedied by education . </P> <P> In 1916 a team of psychologists, led by Robert Yerkes and including Terman and Henry H. Goddard, adapted the Stanford - Binet tests as multiple choice group tests for use by the US army . In 1919, Yerkes devised a version of this test for civilians, the National Intelligence Test, which was used in all levels of education and in business . Like Terman, Goddard had argued in his book, Feeble - mindedness: Its causes and consequences (1914), that "feeble - mindedness" was hereditary; and in 1920 Yerkes in his book with Yoakum on the Army Mental Tests described how they "were originally intended, and are now definitely known, to measure native intellectual ability ." Both Goddard and Terman argued that the feeble - minded should not be allowed to reproduce . In the USA, however, independently and prior to the IQ tests, there had been political pressure for such eugenic policies, to be enforced by sterilization; in due course IQ tests were later used as justification for sterilizing the mentally retarded . </P> <P> It was also argued that the IQ tests should be used to control immigration to the USA . Already in 1917 Goddard reported on the low IQ scores of new arrivals at Ellis Island; and Yerkes argued from his army test scores that there were consistently lower IQ levels amongst those from Eastern and Southern Europe, which could lead to a decline in the national intelligence . In 1923, in his book A study of American intelligence, Carl Brigham wrote that on the basis of the army tests, "The decline in intelligence is due to two factors, the change in races migrating to this country, and to the additional factor of sending lower and lower representatives of each race ." He concluded that, "The steps that should be taken to preserve or increase our present mental capacity must of course be dictated by science and not by political expediency . Immigration should not only be restrictive, but highly selective ." The Immigration Act of 1924 put these recommendations into practice, introducing quotas based on the 1890 census, prior to the waves of immigration from Poland and Italy . While Gould and Kamin argued that the psychometric claims of Nordic superiority had a profound influence on the institutionalisation of the 1924 immigration law, other scholar's have argued that "the eventual passage of the' racist' immigration law of 1924 was not crucially affected by the contributions of Yerkes or other psychologists ." </P> <P> In the 1920s psychologists started questioning underlying assumptions of racial differences in intelligence; although not discounting them, the possibility was considered that they were on a smaller scale than previously supposed and also due to factors other than heredity . In 1924 Floyd Allport wrote in his book "Social Psychology" that the French sociologist Gustave Le Bon was incorrect in asserting "a gap between inferior and superior species" and pointed to "social inheritance" and "environmental factors" as factors that accounted for differences . Nevertheless, he conceded that "the intelligence of the white race is of a more versatile and complex order than that of the black race . It is probably superior to that of the red or yellow races ." </P>

Who cited in his book that hereditary is one of the causes of crime