The Messianic Effect of Pathological Altruism

Jorge M. Pacheco and Francisco C. Santos

in Pathological Altruism

Published in print December 2011 | ISBN: 9780199738571
Published online January 2012 | e-ISBN: 9780199918669 | DOI:
The Messianic Effect of Pathological Altruism

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Previous research in evolutionary game theory has shown that cooperation is not an evolutionarily viable strategy unless additional mechanisms are put into play, as the tragedy of the commons is often the ensuing doomsday scenario. This chapter presents a surprisingly elegant solution to this paradox, resorting to a mathematic model of pathological altruists in a stereotypical noncooperative game: the Prisoner’s Dilemma. Pathological altruists are defined as individuals incapable of changing their altruistic behavior, and hence unresponsive to the stimuli of greed and fear. We show how the presence of pathological altruists induces a polymorphic equilibrium between defectors and cooperators. Whenever selection pressure is weak, a single pathological altruist can obliterate the evolutionary advantage of defectors, thus providing a messianic effect for the community as a whole. Our model does not explicitly address the fundamental question of how pathological altruism emerges, but hints at an a posteriori justification for its viability.

Keywords: evolution of cooperation; game theory; pathological altruism; messianic effects; selection pressure

Chapter.  5220 words.  Illustrated.

Subjects: Social Psychology

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