The influence of landmark salience in a navigation task: an additive effect between its components

In 2 experiments, rats were trained in a Morris pool to find a hidden platform in the presence of 1 landmark. After acquisition, the rats were tested without the platform. Experiment 1 tested whether the size of a landmark and its relative distance from the platform are additive effects. On test, the rats' best performance was with a near and big landmark; intermediate performance was with either a near and small landmark or a far and big one; and the worst performance was with a far and small landmark. The results of Experiment 2 suggested that the different distances from the goal of the 2 landmarks might not be sufficient to explain the previous results.