Encyclopedia of Evolutionary Psychological Science

Living Edition
| Editors: Todd K. Shackelford, Viviana A. Weekes-Shackelford

Hamilton’s Rule

  • Hans HämäläinenEmail author
  • Antti O. Tanskanen
  • Mirkka Danielsbacka
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-16999-6_1357-1



According to Hamilton’s rule, the cost of an investment must be less than the benefit weighted by the genetic relatedness of the investor and recipient. Based on the condition “all else being equal,” individuals are predicted to invest more in closely genetically related kin compared to more distantly related kin or non-kin.


William D. Hamilton (1964) formulated a rule that defined the conditions under which altruism can evolve and spread in sexually breeding populations. Altruism refers to a behavior that decreases the fitness of the actor while increasing the fitness of another individual (West et al. 2011).

The Rule

Hamilton argued that in addition to the parent–offspring relation, other relatives who share a common descent carry identical copies of the same alleles (Mock 2011). Therefore, individuals can spread their own genes (inclusive fitness) not only by reproducing themselves (direct...
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  1. Hamilton, W. D. (1964). The genetical evolution of social behaviour I & II. Journal of Theoretical Biology, 7, 1–52.CrossRefGoogle Scholar
  2. Mock, D. W. (2011). The evolution of relationship in nonhuman families. In C. A. Salmon & T. K. Shackelford (Eds.), The Oxford handbook of evolutionary family psychology (pp. 211–229). Oxford: Oxford University Press.Google Scholar
  3. Salmon, C. A., & Shackelford, T. K. (2011). Toward an evolutionary psychology of the family. In C. A. Salmon & T. K. Shackelford (Eds.), The Oxford handbook of evolutionary family psychology (pp. 3–11). Oxford: Oxford University Press.Google Scholar
  4. West, S. A., El Mouden, C., & Gardner, A. (2011). Sixteen common misconceptions about the evolution of cooperation in humans. Evolution and Human Behavior, 32, 231–262.CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Hans Hämäläinen
    • 1
    Email author
  • Antti O. Tanskanen
    • 2
  • Mirkka Danielsbacka
    • 3
  1. 1.Pompeu Fabra UniversityBarcelonaSpain
  2. 2.University of TurkuTurkuFinland
  3. 3.Population Research Institute of FinlandHelsinkiFinland

Section editors and affiliations

  • Douglas Sellers
    • 1
  1. 1.Penn State Worthington ScrantonScrantonUSA