An Eight-Alternative Concurrent Schedule: Foraging in a Radial Maze

In two experiments conducted in an eight-arm radial maze, food pellets were delivered in the arms according to interval schedules of reinforcement. The behavior of rats in this situation was well-described by the generalized matching law that is, there was a linear relationship between log behavior ratios and log pellet ratios. The slopes of these functions, an index of sensitivity to reinforcement frequency, were greatest for nose pokes, intermediate for time spent in an arm, and least for arm entries. Addition of a 10-second changeover delay eliminated the slope differentials between nose pokes and time spent by reducing the slopes of the nose poke functions. These results suggest that different aspects of foraging are differentially sensitive to reinforcement. Further, the results validate the use of this animal model for the assessment of stress and drug effects on behavior.