Fig. 4.

Learning curves for experiment 5 a and b. Triangles depict performance in distinguishing between two topologically different stimuli (an S and a ring, as in Fig. 2). Circles depict performance in distinguishing between two topologically equivalent stimuli (a disk and a square). The dashed line depicts the random choice level (50%). Twelve blocks were run for each pair of stimuli to attain the plateaus of the learning curves. Total choices in each block range from 28 to 43.