Enhancement of acquistion and performance of level-pressing behavior in rats by an experimental diet

Rats given diets containing jack bean had superior performance during learning and testing of level pressing compared with rats given control diets. To evaluate the factors which might have contributed to the differences in their performance, the testing conditions, testing schedules, and the reinforcement were varied. The results strongly suggested that the rate of learning depended largely on factors inherent within the individual animals. The rats preferred the reinforcement, Noyes pellets, to diets containing jack bean. Therefore the superior performance of rats given diets containing jack bean could be, to a certain extent, due to their motivation to lever press for Noyes pellets. However, there was also evidence suggesting that other factors in jack bean enhanced the behavioral performance of rats when water droplets were used as the reinforcement.