Abstract
2 adult male squirrel monkeys, Saimiri sciureus, were conditioned on titration schedules of reinforcement which enabled the animals to adjust sucrose concentrations of Noyes 190-mg. food pellets received as reinforcers. Responding on a titration operandum increased available sucrose concentrations by 20% for 30 sec. per titration response. An alternate operandum, which required a response of different topography, produced reinforcers of sucrose concentration determined by titration rate under a FR 30 schedule. Regular insulin, U-40, was administered via the intraperitoneal route in four doses. Highest and lowest doses of insulin resulted in highest sucrose proportion acquired. Intermediate doses resulted in lowest sucrose proportion acquired.