Experiment 1 revealed that male four zebrafishs, aged 110 days after birth without pre-perceptual
learning of either black triangles nor black circles choose significantly more a inverted black triangle presented on the right saide to a black circlE' presented to the left side without food reinforcement. The outeriengths of both figures are same. Experiment 2 revealed that the same zebrafishs choose significantly more again the same inverted black triangle, presented on left side this time, to a black circle presented on right side.