Arthur Jensen has argued that genetic differences in abstract reasoning ability, not cultural bias in the test item, are the causes of differences in standardized test performance between American Blacks and Whites. He used a study by Frank McGurk to support his argument. McGurk's study used test items judged most cultural or least cultural. These were administered to a sample of pairs of black and white high school seniors matched on age, educational status, and other demographic characteristics. The authors analyzed the McGurk study. They found an analysis of the data demonstrates that black-white differences are constant across the major types of tasks used in tests of mental ability. Abilities tested are association note memory, abstract reasoning and problem solving ability. (DWH)