Latent learning in a swimming pool place task by rats: evidence for the use of associative and not cognitive mapping processes.

Using a latent learning paradigm, the experiments examine two hypotheses of how rats solve place navigation tasks. According to associative theory, experience with all relevant cues is required for accurate navigation. According to cognitive mapping theory, animals can generate novel trajectories from knowledge of spatial relations of objects in the environment. Rats that had been placed on a platform, which was submerged in a pool of opaque water and was moved each day, were tested later for their ability to find the platform using only surrounding room cues. One 30-sec exposure to a platform location was effective in improving performance. Improvement was greatest when tests were given within minutes of placement, but facilitation was obtained for as long as 4 hr. Improved performance was obtained as soon as rats acquired the procedural aspects of the task but did not increase with subsequent practice. Improved performance was also obtained when pre-trained rats were tested in a novel environment. Despite the advantage conferred by exposure to the target platform, test swims were not accurate, placement-induced improvement was not as great as that following a single swimming trial, and placement combined with a swim resulted in best performance. The results suggest that rats use associative learning processes rather than cognitive mapping to solve place problems in a swimming pool.