Fig. 4. (A–D) Choice frequencies of six fishes in transfer tests, during which the S+ used during training was replaced by a novel object. Each bar depicts the choice frequency for the left object (novel object or S+) of each pair. Below each bar, the object replacing S+ is named. `Ratio' is the volume ratio of the two objects offered, with the volume of the right object (S–) divided by the volume of the left object (novel object, except for training conditions, far right columns). Other details as in Fig. 3.