Encyclopedia of Evolutionary Psychological Science

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

Benefit to Another at Cost to Self

  • Terence BurnhamEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-16999-6_1476-1



Altruism is defined as a voluntary costly act that benefits another organism, usually a conspecific (see Table 1).
Table 1

Altruism in a framework of effects on self and other(s)


Cost to another

Benefit to another

Cost to actor



Benefit to actor




The study of altruism dates back at least to Darwin, who wrote, “Can we consider the sting of the wasp or of the bee as perfect which … inevitably causes the death of the insect”? (Darwin 1859) (Chapter 6). Darwin wondered how suicidal bee stings could persist – shouldn’t the stinging bees lose the evolutionary competition to other bees that do not commit suicide? There are currently five accepted theories that explain altruism and one open debate.

All of the accepted theories share the same underlying logic. The genes that create the apparently altruistic behavior benefit from the behavior. What appears to be altruistic is, in fact, selfish, when viewed from the perspective of the genes.

Accepted Theory #1: Kin Selection

Kin selection (Hamilton 1964) explains costly acts as benefiting genes in relatives. A bee may die when it stings an invader. This is bad for the individual bee, but good for the genes in the bee that are also likely to be shared by the other bees in the same hive. Altruistic behaviors that benefit genetic relatives help the underlying genes increase in the population.

Accepted Theory #2: Reciprocal Altruism

Reciprocal altruism (Trivers 1971) examines costly acts in the context of relationships. A person might sacrifice for a friend today and be repaid in the future. One act, examined in isolation, appears to be altruistic; when summed over the individuals’ lifetimes, however, the relationship benefits all parties.

Accepted Theory #3: Indirect Reciprocity

Indirect reciprocity (Alexander 1979; Nowak and Sigmund 1998) sees future repayment as the explanation for costly acts. Indirect reciprocity is similar to reciprocal altruism in counting costs and benefits over an organism’s lifetime. The apparent altruism is repaid in the context of the relationship. One difference, however, is that reciprocal relationship sees the repayment coming from the individual who was helped, while indirect reciprocity allows repayment by third parties.

Accepted Theory #4: Costly Signaling

Costly signaling (Zahavi 1975) explains altruistic acts as part of a longer-term reputation management strategy. The costly act may alter the reputation of the “altruist.” The ability to help out someone in need may demonstrate, for example, health and vigor of the altruists. This perception of health and vigor might change the behavior of other organisms in a way that more than compensates for the altruist act.

Accepted Theory #5: Group Selection

Group selection (Wilson and Sober 1994) occurs when altruistic acts benefit the group in a way that also helps the genes of the altruist. If groups break up and reform with sufficient regularity, then even though the altruist does sacrifice for the benefit of the group, the genes of the altruist can increase as a percent of the overall population.

Open Debate: Strong Reciprocity

Strong reciprocity (Fehr et al. 2002) is purported as the sixth explanation for altruistic acts. For example, people in anonymous laboratory experiments in large cities will give money to strangers under some circumstances (Kahneman et al. 1986). These altruistic acts cannot be repaid through any of the five accepted theories. The participants are not kin, ruling out kin selection. The acts are anonymous so cannot be repaid through direct or indirect reciprocity. Similarly, no signals can be sent in an anonymous setting, so costly signaling is not possible. Finally, the participants are not in evolutionary relevant groups, thus ruling out group selection (Burnham and Johnson 2005). Strong reciprocity faces continued debate about its existence and relevance.


The field of altruism has undergone tremendous change in the last few centuries and decades. There are five widely accepted explanations for altruistic behavior.



  1. Alexander, R. D. (1979). Natural selection and social exchange. In R. L. Burgess & T. L. Huston (Eds.), Social exchange in developing relationships. New York: Academic.Google Scholar
  2. Burnham, T. C., & Johnson, D. (2005). The biological and evolutionary logic of human cooperation. Analyse & Kritik, 27, 113–135.CrossRefGoogle Scholar
  3. Darwin, C. (1859). On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray.CrossRefGoogle Scholar
  4. Fehr, E., Fischbacher, U., & Gachter, S. (2002). Strong reciprocity, human cooperation and the enforcement of social norms. Human Nature, 13, 1–25.CrossRefPubMedGoogle Scholar
  5. Hamilton, W. D. (1964). The genetical evolution of social behavior I and II. Journal of Theoretical Biology, 7(1), 1–16, 17–52.CrossRefPubMedGoogle Scholar
  6. Kahneman, D., Knetsch, J., & Thaler, R. (1986). Fairness and the assumptions of economics. Journal of Business, 59(4), S285–S300.CrossRefGoogle Scholar
  7. Nowak, M., & Sigmund, K. (1998). The dynamics of indirect reciprocity. Journal of Theoretical Biology, 194, 561–574.CrossRefPubMedGoogle Scholar
  8. Trivers, R. L. (1971). The evolution of reciprocal altruism. Quarterly Review of Biology, 46(1), 35–57.CrossRefGoogle Scholar
  9. Wilson, D. S., & Sober, E. (1994). Reintroducing group selection to the human behavioral sciences. Behavioral and Brain Sciences, 17(4), 585–654.CrossRefGoogle Scholar
  10. Zahavi, A. (1975). Mate selection – A selection for a handicap. Journal of Theoretical Biology, 53, 205–214.CrossRefPubMedGoogle Scholar

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© Springer International Publishing AG 2016

Authors and Affiliations

  1. 1.Chapman UniversityOrangeUSA

Section editors and affiliations

  • Minna Lyons
    • 1
  1. 1.University of LiverpoolLiverpoolUK