Reward and purpose as incentives for children differing in locus of control expectancies.

The Intellectual Achievement Responsibility Questionnaire was used to classify 248 fourth- and fifth-graders as internals, mediums, and externals on the internal-external locus of control personality dimension. Subjects were assigned to four treatment groups resulting from the manipulation of intrinsic (purpose vs. non purpose) and extrinsic (reward vs. no reward) motivational conditions and administered a coding task with number of figures coded as the dependent variable. An analysis of variance with IE, reward, purpose, sex, and grade as factors yielded significant purpose, sex, grade, and IE X Reward X Purpose effects. The performance of internals was found to be unaffected by motivational manipulations; purpose together with reward improved the performance of mediums: reward and purpose (individually and together) improved the performance of externals. Implications for future investigation of the IE construct and the social psychology of psychological research were discussed.