Changes in rate of schedule-induced behaviour in rats as a function of fixed-interval schedule

Abstract

Two experiments were conducted to determine the way in which rate of adjunctive drinking and food-tray responding vary as a function of interreinforcement interval duration. In Experiment I rats were tested under fixed-interval schedules ranging from 1–60 s in duration, and in Experiment II under fixed-interval schedules ranging from 1–180 s in duration, with food as the reinforcer. The rate of drinking increased and then declined as interreinforcement interval increased, reaching a maximum under intervals of about 45 s. The rate of food-tray responding declined over the whole range of schedules. It is concluded that drinking can meaningfully be described as “schedule-induced”, in the sense of being directly facilitated by intermittent schedules of reinforcement; but this is less certain in the case of food-tray responding.