>>> 2007年スタンフォード大学の学者たちが発表したのと同じじゃん
www.nature.com/nature/journal/v445/n7126/abs/nature05511.html
Fish can infer social rank by observation alone
Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning.
First described as a developmental milestone in children1, TI has since been reported in nonhuman primates2, 3, 4, rats5, 6 and birds7, 8, 9, 10.