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Egalitarian motives in humans

Nature volume 446, pages 794796 (12 April 2007) | Download Citation



Participants in laboratory games are often willing to alter others' incomes at a cost to themselves, and this behaviour has the effect of promoting cooperation1,2,3. What motivates this action is unclear: punishment and reward aimed at promoting cooperation cannot be distinguished from attempts to produce equality4. To understand costly taking and costly giving, we create an experimental game that isolates egalitarian motives. The results show that subjects reduce and augment others’ incomes, at a personal cost, even when there is no cooperative behaviour to be reinforced. Furthermore, the size and frequency of income alterations are strongly influenced by inequality. Emotions towards top earners become increasingly negative as inequality increases, and those who express these emotions spend more to reduce above-average earners' incomes and to increase below-average earners' incomes. The results suggest that egalitarian motives affect income-altering behaviours, and may therefore be an important factor underlying the evolution of strong reciprocity5 and, hence, cooperation in humans.

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We thank the Center for Adaptive Behaviour and Cognition at the Max Planck Institute for Human Development and the UC Davis Institute of Government Affairs for generous research support.

Author Contributions The authors are listed alphabetically because each author contributed equally to the design, implementation, analysis and communication of this research.

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  1. Department of Political Science, University of California, San Diego, California 92093, USA

    • Christopher T. Dawes
    •  & James H. Fowler
  2. Center for Adaptive Behaviour and Cognition, Max Planck Institute for Human Development, Lentzeallee 94, Berlin 14195, Germany

    • Tim Johnson
  3. Department of Political Science, Stanford University, Palo Alto, California 94305, USA

    • Tim Johnson
  4. Department of Anthropology, University of California, Davis, California 95616, USA

    • Richard McElreath
  5. Department of Political Science, University of Miami, Coral Gables, Florida 33124, USA

    • Oleg Smirnov


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Competing interests

Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.

Corresponding author

Correspondence to James H. Fowler.

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