Two studies were carried out to establish the generality of Baron and Ganz's finding of a significant Locus of Control X Type of Performance Feedback interaction. The superior performance of internals to externals under a condition of self-discovery of success (intrinsic feedback), as opposed to the superior performance of externals to internals when unverifiable verbal praise is used (extrinsic feedback), was found to occur for lower-class white as well as lower-class black subjects (Study 1), and for college students (Study 2). Study 2 also used a different measure of locus of control, a different problemsolving task, and new procedures for operationalizing the type of feedback variable. Taken together, these studies were seen as providing strong evidence of the generality and usefulness of the Personality X Treatment interaction design in the area of locus of control.