About the Authors

Reiko Matsunaka

Affiliations Graduate School of Arts and Sciences, Department of General System Studies, The University of Tokyo, Tokyo, Japan, CREST, Japan Science and Technology Agency, Saitama, Japan

Kazuo Hiraki

khiraki@idea.c.u-tokyo.ac.jp

Affiliations Graduate School of Arts and Sciences, Department of General System Studies, The University of Tokyo, Tokyo, Japan, CREST, Japan Science and Technology Agency, Saitama, Japan

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: RM KH. Performed the experiments: RM. Analyzed the data: RM KH. Wrote the paper: RM KH.