Variation in arm‐choice strategies of rats in radial‐maze tasks[Note 1. This research was partly presented at the 58th annual ...]

Rats were trained with three delay‐interpolated tasks in a radial‐arm maze. The tasks differed in the post‐delay bait conditions. When every arm was baited in the post‐delay free choices (Task E8B), rats made adjacent‐arm choices frequently. When only the four arms unvisited in the pre‐delay forced choices were baited after delay (Task U4B), rats chose unvisited arms preferentially, with frequent arm investigations. When four quasi‐randomly selected arms were baited after delay (Task R4B), rats did not choose adjacent arms as frequently as the rats in Task E8B did, and made fewer arm investigations. These results indicate that the rats developed different arm‐choice strategies in accordance with tasks. As for the effects of rewarding, post‐delay choice behavior was not affected by the pre‐delay bait conditions.