Physical Constraints on the Evolution of Cooperation

The evolution of psychological adaptations for cooperation is still puzzling due to a tendency to frame social interaction in mathematical and game-theoretical terms, without systematically examining its causal structure and underlying mechanisms. Complementarily, empirical approaches to cooperation tend to focus on isolated components of mechanisms without sufficiently indicating how different components are combined into a single mechanism and different mechanisms fit into a single organism. An alternative approach to the evolution of cooperation is proposed, starting from a description of basic physical properties of individuals and their environment, and the limited physical or mechanistic possibilities to generate adaptive responses to those properties. This approach reveals that some forms of symmetrical cooperation do not require mechanisms “specifically designed for” benefiting others, whereas effective helping requires a specific mechanism that relatively unconditionally and persistently responds to the vulnerability of other individuals. Unraveling the causal structure of different types of other-benefiting shows that a mechanism for asymmetrical helping may considerably improve symmetrical cooperation through properties such as tolerance, patience, and the human capacity to experience a wide variety of moral emotions. The proposed mechanistic approach to cooperation provides the mathematical/game-theoretical approach with realistic assumptions about psychological adaptations, and helps to integrate the scattered facts about mechanisms gathered by the empirical approach. It also helps to build bridges between the two approaches by providing a common language for thinking about psychological mechanisms.