Foraging by Rats on a Radial Maze: Learning, Memory, and Decision Rules
William A. Roberts
University of Western Ontario
The research I discuss represents a blending of two areas of investigation, spatial memory and foraging. Beginning with the seminal article of Olton and Samuelson ( 1976), a number of experiments have been carried out on the radial maze to find out how rats and other animals remember and forget spatial information. This research has revealed that rats can remember a large number of locations visited ( Olton, Collison, & Werz, 1977; Roberts, 1979) and that the format of memory is maplike and based on extramaze visual cues ( Mazmanian & Roberts, 1983; Suzuki, Augerinos, & Black, 1980). Although rats can remember locations visited on the radial maze over several hours ( Beatty & Shavalia, 1980), forgetting can arise from both proactive and retroactive interference caused by other spatial experiences ( Roberts, 1981; Roberts & Dale, 1981).
If one reflects on the functional role of spatial memory, it seems clear that spatial memory promotes fitness in rats and other animals ( Shettleworth, 1983). Specifically, spatial memory allows animals to remember where in space a number of places are located that are vital to survival, such as food locations, the location of home base, and the locations of potential predators and conspecifics. Spatial memory also allows an organism to keep track of its own movements through a spatial landscape and prevents redundant visits to locations recently visited. Finally, animals not only remember locations in their environment but also remember the contents of those locations or important events that occurred at those locations.
Much of this concern with the functional role of spatial memory is incorporated within the second area of investigation, foraging theory. Spatial memory may be seen to be at the service of foraging strategies that tend to maximize the