To differentiate behaviorally, success-strivers and failure-avoiders within a group of educable mentally handicapped, two experiments were conducted. The effects of learning potential status (gainers, nongainers, high scorers) and motivational style (success strivers, failure avoiders) on discrimination learning when reinforcement was varied was examined. In the first experiment 24 educable mentally handicapped black adolescents from a low income housing area were tested using trials-to-criterion as the dependent variable in a two choice simultaneous discrimination problem. Only the learning potential, motivation interaction combination was felt to approach significance. Experiment II was modified only in certain test procedures. Twenty four white boys from lower class families were tested with modifications in motivational assessment, incentive, and cue set procedures. Contrary to prediction, it was concluded that the negative motivational feedback did not yield greater efficiency for the success-strivers. Results were felt to confirm the prediction that gainers and high scorers would be superior to nongainers on the discrimination task. The validity of the construct of failure-avoidance versus success-striving as it has been applied to the mentally handicapped group was questioned by the researchers. (CD)