Cooperation can occur without trust, since animals cooperate without mental trust states.

Evidence

These questions about the evolution of cooperation do not bear directly on the issue of trust, though they may give pause to anyone who supposes that trust is required for effective cooperation (defined simply in terms of working with and assisting others). To maintain such a position it would be necessary to argue that, for example, honey bees trust each other. Even though the study of cooperation in animals seems irrelevant to an understanding of trust in humans, careful analysis of the conditions in which cooperative behaviour is expressed suggests that many animals are exquisitely sensitive to the behaviour of others. This observation suggests an explanation for the evolution of the mental state that we recognize as trust in outselves. — Diego Gambetta, Trust - Making and Breaking Cooperative…, 245

Categorization

• XREF: Directly relevant to the reader’s Luhmann/Hardin synthesis: cooperation and trust are separable phenomena, with behavioral sensitivity to others’ behavior as a precursor to trust as a mental state.
• SEED: An angle: ‘cooperation without trust’ — decoupling prosocial behavior from internal trust states has implications for institutional design.