Revenge: an adaptive system for maximizing fitness, or a proximate calculation arising from personality and social-psychological processes?

Revenge appears among a “suite” of social interactions that includes competition, alliance building (a prerequisite for tribal revenge raids), and so forth. Rather than a modular “system” directly reflecting evolutionary fitness constraints, revenge may be (another) social cost-benefit calculation involving potential or actual aggression and proximately controlled by individual personality characteristics and beliefs that can work against fitness.