A study was conducted to determine whether conventional instruction and mastery-based auto-tutorial instruction interacted with learning characteristics that were found to be instruction-interactive in previous research. Conventional instruction consisted of lecture with discussion and laboratory periods. The mastery-based auto-tutorial instruction consisted of multi-media modules that the learner studied until mastery was attained, and student-teacher communication was minimal and occurred only in individual discussions. Undergraduates enrolled in an undergraduate course in wildlife recreational techniques were administered the following tests: the Ac (achievement via conformance) and Ai (achivement via independence) scales of the California Psychological Inventory, the internal-external locus of control scale (Rotter, 1966), a multiple-choice achievement test covering content from the experimental unit, a delayed achievement test developed and administered eight and one-half weeks after the experimental period, and semantic differential scales designed to measure student attitudes. The findings indicate that one can enhance learning by using Ac scores to match students with an instructional treatment. Students with low Ac scores achieved better when assigned to mastery instruction and students with high Ac scores achieved better when assigned to conventional instruction. (SW)