title: Altruism among non-relatives: alternatives to the 'Prisoner's Dilemma'.
abstract: Triver's model of reciprocal altruism, and its descendants based on the Prisoner's Dilemma model, have dominated thinking about cooperation and altruism between non-relatives. However, there are three alternative models of altruism directed to non-relatives. These models, which are not based on the Prisoner's Dilemma, may explain a variety of phenomena, from allogrooming among impala to helping by non-relatives in cooperatively breeding birds and mammals.
authors.affiliation: Division of Biological Sciences and The Michigan Society of Fellows, Museum of Zoology, University of Michigan, Ann Arbor MI, 48109, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Connor