They say Eastern Asians (Japanese, Chinese, and Koreans), score on average a few points higher than Whites. They also say that Whites score 15 points higher than African-Americans. They attribute these differences in scores to genetic differences. Again, their critics say that the environment is responsible for IQ, and that African-Americans have had to endure a history of racism and slavery, in which the effects are still felt today on their IQ scores. They hypothesize that as African-Americans gain an equal place in society, their average IQ scores will rise. .
Herrnstein and Murray also contend that between 40 and 80 percent of cognitive ability is genetic, and therefore heritable. They say that means that African-Americans score lower on IQ tests, on average, and that they are born that way. They claim efforts to improve cognitive ability through better education or living conditions will have limited returns due to the genetic factor. .
Definitions of Intelligence.
There is no one set definition of intelligence. Even Psychometricians, who study and measure intelligence, do not agree on the "correct" definition. One definition could be "the ability to reason, learn quickly, analyze and solve new problems, and grasp abstract or complex concepts- skills measured by standard intelligence tests" (Genetics and Intelligence, p.12). Even Educational Psychologists would dispute that intelligence is the ability to learn- to modify one's behavior based on past experiences. This is not just a human characteristic, animals learn from their experiences as well. Although, what separates human and animal learning is the fact that humans can think abstractly.
History of Intelligence Testing.
.
Alfred Binet devised the first intelligence test in 1905 as a way to identify students who needed extra help in class. Along with Theodore Simon, he devised a scheme for classifying each test taker according to "mental age.
