The Quantitative Analysis of Economic Behavior With Laboratory Animals

Molar Effects of Increasing Amounts and Immediacy to External Food Sources in 4-Hr Sessions

“…The present experiment replicated some conditions in Experiment 2 of the Hursh et al (1989) study. In that experiment, monkeys worked in four 1-hr sessions interspersed with 5-min periods of continuous reinforcement.…”

“…If the results of Timberlake showed species-specific effects (see 1984, p. 123), the temporal distance of available substitutes should produce no differential effects on work-session responding and/or food consumption. The present study is a systematic replication of the Hursh et al (1989) study using rats as partiCipants. We varied the amount of response-independent food provided outside test sessions according to fixed-time (FT) schedules in different conditions for rats following 4-hr long sessions.…”

“…In the Hursh et al (1989) study, monkeys worked in 12-hr long sessions and received different amounts of external food in different conditions. In Experiment 1, the external food was provided immediately after the session whereas, in Experiment 2, it was provided after four 1-hr work periods distributed across the 12-hr period in one or four blocks of free food.…”

“…In the Hursh et al (1989) study, the independence between responding and food consumption defined open economies (Hursh, 1980). By increasing the amount of external food relative to work periods, the economies increasingly were more open compared to the strictly closed economy established in baseline where no free food was available.…”

“…One important difference between the Hursh et al (1989) and the Timberlake (1984) studies was that the species studied was different: Rhesus monkeys (Macaca mulata) and Sprague-Dawley rats, respectively. If the results of Timberlake showed species-specific effects (see 1984, p. 123), the temporal distance of available substitutes should produce no differential effects on work-session responding and/or food consumption.…”