How taking turns communicates desired equality in social relationships

When people perform generous acts for each other, they can balance out relative benefits by alternating who is generous. When and why do they do this? Here we test the explanation that sequences of generosity regulate social relationships. We find that people selectively expect reciprocal generosity in equal (vs. hierarchical) relationships, use reciprocal generosity to infer the presence of an equal relationship, and critically expect that people reciprocate generosity in order to communicate a desire for a (more) equal relationship. In a formal planning model, reciprocal generosity can emerge from the value of communicating desired equality.