Figure 1
From: Competitive environments sustain costly altruism with negligible assortment of interactions
Hamilton's inclusive-fitness model applied to pairwise interactions.
(a) Cooperator-Defector and (b) Cooperator-Cooperator, following the schema of ref. 25. Given players of equal fitness before interacting (squares), each interaction (dashed connector) has payoffs for actor (triangle) and recipient (circle) that take Table 1a parameters for b as a conferred benefit and Table 1b parameters for b as a public good. The inclusive fitness payoff for each player is the summed effect of its actions on itself plus the effect of its actions on others weighted by relatedness r24.
