About the Authors

Shigeru Watanabe


Affiliation Department of Psychology, Keio University, Mita 2-15-45, Minato-Ku, Tokyo, Japan

Competing Interests

The author has declared no competing interests exist.

Author Contributions

Conceived and designed the experiments: SW. Performed the experiments: SW. Analyzed the data: SW. Contributed reagents/materials/analysis tools: SW. Wrote the paper: SW.