Figure 1.

(A) Schematic representation of the water maze and the possible positions that were occupied by the intramaze landmark (black circle) and the hidden platform (dashed circle) in Experiment 1. Various shapes outside the pool represent the extramaze cues (schematic only; not to scale). The same landmark-platform position was used within each session of four trials but for every session a novel position was selected from 16 potential positions (only eight are shown here for ease of exposition). Half of the subjects were trained with the platform 30 cm due north of the landmark (as shown), while the other half was trained with the platform 30 cm due south. (B) The design of the landmark test. The landmark was placed at the center of the pool for the first time. The notional correct and incorrect zones (C,I) were set for data analysis with their centers positioned 30 cm due north or south of the landmark. (C) The design of the place test. The three training trials (on the left panel) were followed by a probe trial (on the right panel) in which the landmark and platform were removed. Notional zones were set at the previous platform location (C; correct) and its diametrically opposite location (I; incorrect).