This debate focuses on the results of studies that show a difference in average I.Q. levels between African Americans and white Americans. Innis objects to the idea of a "racial I.Q. deficit" and questions the ability of scientists to accurately measure intelligence. He claims that the I.Q. test is strongly influenced by environmental variables, thus is not a reliable test of true intelligence. Shockley argues that humanity and technology have advanced to the point where it is indeed possible to objectively test intelligence; he also acknowledges that some studies do show the influence of environmental variables, and he suggests ways to control for this effect.