FOR BETTER OR WORSE: EFFECT OF UPCOMING REINFORCER TYPE ON RATSu27 LEVER PRESSING FOR LOW-CONCENTRATION SUCROSE REINFORCERS

摘要

Recent research has demonstrated that food-pelletreinforcement upcoming in the second half of an experimentalsession can increase operant response rates for low-concentrationliquid-sucrose reinforcers in the first half. The present studyinvestigated whether an upcoming reinforcer other than foodpellets could produce a similar increase (Experiment 1) andwhether a decrease in responding would be observed byworsening the upcoming conditions of reinforcement (Experiment2). Experiment 1 demonstrated that ratsu27 rates of lever pressing for1 or 5% liquid-sucrose reinforcers delivered by a random-interval60-s schedule during the first half of a 50-min session weresimilarly increased by the delivery of food or sucrose pellets in thesecond half. Experiment 2 demonstrated that rates of leverpressing for 5% liquid-sucrose reinforcers in the first half of thesession were increased and decreased by upcoming food-pelletand 1 % liquid-sucrose reinforcement, respectively. The resultsfrom both experiments represent induction (i.e., a directrelationship between rate of responding and the upcomingconditions of reinforcement). They suggest that the induction maybe both general (i.e., not limited to specific upcoming reinforcers)and symmetrical (i.e., manifesting in either an increase or adecrease in responding), the latter of which provides a potentiallink to the study of behavioral contrast.