Defectors, vulnerability and relative power: Some causes and effects of leaving a stable coalition

This study explored the causes and effects of defecting from a stable coalition. Vulnerability and the relative power of the defectors were the primary independent variables. Results showed that defectors were obtaining higher payoffs than nondefectors prior to their defection. Defection from stable coalitions in the four coalition games studied here led to reduced benefits for both the defectors and the nondefectors. At the same time defectors fared better than nondefectors, with vulnerability reducing the defectors' benefits. Relative power, over all conditions, led to significantly more positive outcomes than relative equality or weakness. The data also suggested that vulnerable defectors may fare more poorly than their nondefecting partners. The use of coalitions as models of a variety of interactions and the social contexts that facilitate or block defections are also discussed.