AUTHOR=Berra Irene TITLE=An evolutionary Ockham's razor to reciprocity JOURNAL=Frontiers in Psychology VOLUME=5 YEAR=2014 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2014.01258 DOI=10.3389/fpsyg.2014.01258 ISSN=1664-1078