Racism is the belief that certain races are superior to others based solely on physical characteristics. While racism has existed throughout human history, science has both disproven many racist theories and unfortunately also helped support some ideals in some cases, such as physiognomy. Modern science has shown that differences in IQ scores between races are due to environmental factors like education rather than genetics. However, some studies like The Bell Curve continue to be used to argue racist views about genetic intellectual differences between populations.