Kinship, Incentives and Evolution

Ingela Alger (1) , Jörgen Weibull (2, 3)

1 Carleton University
2 SSE - Department of Economics
3 X-DEP-ECO - Département d'Économie de l'École Polytechnique

We analyze how family ties affect incentives, with focus on the strategic interaction between two mutually altruistic siblings. The siblings exert effort to produce output under uncertainty, and they may transfer output to each other. With equally altruistic siblings, their equilibrium effort is non-monotonic in the common degree of altruism, and it depends on the harshness of the environment. We define a notion of local evolutionary stability of degrees of sibling altruism, and show that this degree is lower than the kinship-relatedness factor. Numerical simulations show how family ties vary with the environment, and how this a¤ects economic outcomes.

Mots clés: altruism; family ties; free-riding; empathy; Hamilton's rule; evolutionary stability.; evolutionary stability

Domaines: Economies et finances

Ingela Alger, Jörgen Weibull. Kinship, Incentives and Evolution. 2009. ⟨hal-00435431⟩