About the Authors

Charles G. Nathanson

Contributed equally to this work with: Charles G. Nathanson, Corina E. Tarnita

Affiliation Department of Economics, Harvard University, Cambridge, Massachusetts, United States of America

Corina E. Tarnita

Contributed equally to this work with: Charles G. Nathanson, Corina E. Tarnita

corina@math.harvard.edu

Affiliation Program for Evolutionary Dynamics, Department of Mathematics, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America

Martin A. Nowak

Affiliation Program for Evolutionary Dynamics, Department of Mathematics, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Wrote the paper: CGN CET MAN. Conducted the research: CET, CGN, MAN.