Radial arm maze

The radial arm maze was designed by Olton and Samuelson (1976) to measure spatial learning and memory in rats. The apparatus consisted of eight equidistantly-spaced arms, each about 4 feet long, and all radiating from a small circular central platform. At the end of each arm there was a food site, the contents of which were not visible from the central platform. The idea behind this design was to ensure that after checking to see if there was food at the end of each arm the rat was forced to return to the central platform before making another choice, and, as a result, always choosing from among eight options. Using elaborate controls to ensure that the rats were not simply using smell either of unclaimed food objects or of their own tracks, Olton and Samuelson found that rats had excellent memories for visited and or unvisited arms as they made, on average, about 7.0 novel entries in their first 8 choices, and thus were 88% correct. Chance performance with eight arms would be 5.3 novel entries in the first 8 choices (66% correct). Olton and Samuelson also found when they switched some already-visited arms into as yet unvisited locations partway through a trial, the rats tended to visit as-yet unvisited locations even when doing so meant running down arms that had already been traversed, and tended to avoid arms that had not yet been traversed but were now in previously visited locations. It seems that in remembering locations on the radial arm maze, rats do not rely on local intramaze cues, but rather on extramaze cues. The maze has since been used a great deal by researchers interested in studying the spatial learning and spatial memory of animals. For example, Olton, Collison and Werz (1977) found that performance declined only slightly to 82% novel entries in the first 17 entries on a 17-arm maze. Roberts (1979) found no decline in percentage correct choices as the number of arms on a radial maze were increased from 8 to 16 and then to 24. Cole and Chappell-Stephenson (2003) using a radial maze with food locations ranging from 8 to 48 estimated the limit of spatial memory in rats to be between 24 and 32 locations.

References:
Cole, M.R., & Chappell-Stephenson. (2003). Exploring the limits of spatial memory using very large mazes. Learning & Behavior, 31, 349-368.

Olten, D.S., & Samuelson, R.J. (1976). Remembrance of places passed: Spatial memory in rats. Journal of Experimental Psychology: Animal Behavior Processes, 2, 97-116.

Olton, D.S, Collison, C., & Werz, M.A. (1977). Spatial memory and radial arm maze performance of rats. Learning & Motivation, 8, 289-314.

Roberts, W.A. (1979). Spatial memory in the rat on a hierarchical maze. Learning & Motivation, 10, 117-140.