Rather, IQ scores predict equally accurately for all Americans, regardless of race and social class. Not surprisingly, ethnic differences in the mental process of knowing, including aspects such as awareness, perception, reasoning, and judgment are expected. Populations from all over the world have different cognitive abilities. For example, East Asians, such as Japanese, Chinese, Korean, typically obtain higher scores on intelligence test and achievement tests that white Americans. The more complicated and greater comparison can be made between African Americans and white Americans. Recent studies have shown that an average white American is likely to score higher on tests than 84 percent of African Americans and the average African American is likely to score higher on tests than 16 percent of white Americans (Herrnstein & Murray). There has been a great gap between the IQ scores of blacks and whites. Only in the past few decades has the gap decreased by about three IQ points. This decrease in IQ points is mainly because blacks started increasing IQ scores, not by whites decreasing theirs. Some factors that may have added to this decrease in gap may have been the quality of schools attended or even diminishing racism in areas. .
On the other hand, some people believe that some tests are either racially or culturally biased which leads to the differences in test scores for different races and ethnicities. One type of bias, labeling bias, represents that when a test is conducted, it claims to measure one aspect, but really measures another. A perfect example is an aptitude or intelligence test. Many believe that intelligence comes from genes, but now, more and more psychologists agree that not only does genetic makeup affect the scores; the environment influences the scores as well. Another type of bias, content bias, occurs when a test claims to be measuring something that could be measured in an unbiased fashion, but still has questions that are bias to one group over another.