Cumulative deficit is an hypothesis concerning the cause of lower mental test scores of groups considered environmentally deprived. It presupposes a progressive decrement in test scores, relative to population norms, as a function of age. Clarification of the theoretical issues and the methodological problems involved in establishing the…

In these hearings, the following witnesses presented testimony: Dr. Henry E. Garrett, Chairman, Psychology Department (Emeritus), Columbia University; Dr. Arthur R. Jensen, Professor of Educational Psychology, University of California at Berkeley; Dr. Frank C. J. McGurk, Professor of Psychology, University of Montevallo; Dr. R. Travis Osborne,…