In 1916 Terman wrote that Mexican-Americans, African-Americans, and Native Americans have a mental "dullness [that] seems to be racial, or at least inherent in the family stocks from which they come."

The US Army used a different set of tests developed by Robert Yerkes to evaluate draftees for World War I. Based on the Army's data, prominent psychologists and eugenicists such as Henry H. Goddard, Harry H. Laughlin,