title: The evolutionary origin of human hyper-cooperation.
abstract: Proactive, that is, unsolicited, prosociality is a key component of our hyper-cooperation, which in turn has enabled the emergence of various uniquely human traits, including complex cognition, morality and cumulative culture and technology. However, the evolutionary foundation of the human prosocial sentiment remains poorly understood, largely because primate data from numerous, often incommensurable testing paradigms do not provide an adequate basis for formal tests of the various functional hypotheses. We therefore present the results of standardized prosociality experiments in 24 groups of 15 primate species, including humans. Extensive allomaternal care is by far the best predictor of interspecific variation in proactive prosociality. Proactive prosocial motivations therefore systematically arise whenever selection favours the evolution of cooperative breeding. Because the human data fit this general primate pattern, the adoption of cooperative breeding by our hominin ancestors also provides the most parsimonious explanation for the origin of human hyper-cooperation.
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: J M
authors.initials: JM
authors.lastname: Burkart
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 64 Banbury Road, Oxford OX2 6PN, UK.
authors.forename: O
authors.initials: O
authors.lastname: Allon
authors.affiliation: Department of Comparative and Developmental Psychology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Amici
authors.affiliation: Behavioral Ecology and Sociobiology, German Primate Center, Kellnerweg 4, 37077 Goettingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Fichtel
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Finkenwirth
authors.affiliation: Institute of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Heschl
authors.affiliation: Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Huber
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Isler
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Z K
authors.initials: ZK
authors.lastname: Kosonen
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Martins
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: E J
authors.initials: EJ
authors.lastname: Meulman
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Richiger
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Rueth
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Spillmann
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Wiesendanger
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: C P
authors.initials: CP
authors.lastname: van Schaik
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005075:Biological Evolution; D002648:Child; D002675:Child, Preschool; D003299:Cooperative Behavior; D005260:Female; D006801:Humans; D008297:Male; D009042:Motivation; D033281:Nontherapeutic Human Experimentation; D011323:Primates / Q000523:psychology