Evolutionary biologists have proposed several explanations for the evolution of human cooperation. All these explanations (for example kin selection and reciprocal altruism) rely on the assumption that the cost of a cooperative act is recouped and results in an increase in fitness.
Reputation-based cooperation works in a similar fashion. Investing in cooperative reputation pays off because individuals of high reputation enjoy various benefits. These benefits may include being rewarded with cooperation from others and privileged access to desired social partners. Computer simulations suggest that investing in reputation may translate to biological fitness.
Reputation-based cooperation can work through at least two different mechanisms. Cooperative individuals may be rewarded by someone other than the recipient of their own cooperation, a phenomenon known as indirect reciprocity. Alternatively, cooperators may benefit through increased access to social partners and the long-term, profitable interactions they provide – a mechanism dubbed competitive altruism or reputation-based partner choice. This latter mechanism was originally conceptualised by my PhD supervisor, Gilbert Roberts.
During my PhD, I obtained data, which confirmed that investing in reputation, when partner choice is available, brings measurable benefits. To test this, I asked small groups of participants to play behavioural economic games under various conditions (read more about it in this paper). I then compared the effectiveness of competitive altruism and indirect reciprocity at restoring group cooperation (click here to read about our exciting results).