The present article is a comment on the feature “Symmetry: The search for the foundation of thinking, language, and communication” apppeared on Congnitive Studies, 15(3), 2008, from a viewpoint of experimental psychology on the fields of learning and thinking studies. It includes discussion on the biological significance of the experiments both with animal and human, and show the asymmetry of human and animal are not only due to the difference of the biological significance of the experimental situations with referencing data on the retrospective revaluation experiment with human participants. After the discussion, the possibility that the fundamental factor that separates human from infrahuman is the self-concept and self-consciousness is indicated. And in conducting comparative studies on cognitive mechanism and ability, the construction of the model of the self on non-human, such as computer, will be inevitably needed.