The current paper puts forth a new conceptualization for the evolutionary function of morality. Moral alliance strategies theory proposes that our moral psychology can be understood as a tool for managing associations, using the observable behavior of others as an input. The behavior of others is a key input for this system, as it can be used to identify new and profitable alliance potential, to predict where other third parties might side in disputes and as a cue for when existing alliances are liable to become too costly to maintain. Through considerations of how people's behaviors have effects on their association value, a number of facets of our moral psychology-such as impartiality, proportionality, and moral praiseworthiness-can be better understood.Keywords Alliance . Altruism . Morality . Punishment . Praise . Welfare People often take sides in disputes that did not directly involve them for moral reasons (i.e., because someone behaved "immorally" or to defend an individual against claims of wrongdoing). This involvement brings with it the potential for incurring dispute-related costs, such as retaliation from condemned parties and disloyalty to existing allies, leading to a weakening or abandonment of alliances. In order to understand why people take sides in disputes on the basis of moral perceptions, one needs to consider explicitly what compensating advantages individuals might reap from their involvement in these disputes or, alternatively, what costs they might avoid from non-involvement.First, this paper will briefly consider some of the adaptive problems people might be solving by taking sides in disputes more generally, how these adaptive problems might be solved, and what proximate inputs these side-taking mechanisms should be expected to use to solve them. Following that, moral side-taking in particular will be considered and differentiated from non-moral side-taking in terms of inputs. Some contemporary theories of the function of morality will then be discussed. Moral alliance strategies theory (MAST) will then be introduced and discussed. Finally, various features of moral psychology will be framed in terms of MAST to examine how well the theory can account for known findings.
Side-Taking BehaviorDisputes can be conceived of as strategic multiplayer games with different roles that individuals might fill at different times (DeScioli and Kurzban 2009a, b). These roles can be conceived of as actors (those who affect second parties through their behavior), second parties (those who are directly affected by actor behavior), and third parties (those who are not directly affected by actor's behaviors but might support either the actor or the second party). As a running example, consider the following: Person A (the actor) takes a resource from person B (the second party). Person B attempts to retaliate against person A for the action. Person C (the third party) could intervene to either protect A from B or to assist B in harming A.The first question of interest is why third parties might ...