Critical Response

Yerkes won many accolades over the years. He also received his share of criticism, however. The most serious charge was that he let his personal beliefs and feelings override his objectivity. In work on group intelligence testing during World War I, Yerkes was criticized for the racial and ethnic bias that seemed to distort his analysis. In research on primate behavior, he was taken to task for the gender stereotypes that seemed to sway his findings.

Group differences in intelligence

Yerkes reached three controversial conclusions based on data gathered with the Army intelligence tests. First, he claimed that the average mental age in the United States was a mere 13 years. Second, he said there were genetically based racial differences in intelligence, with whites outperforming blacks. Third, he said...