Trivers 1971: altruistic behaviour evolves when recipients reciprocate, provided benefit > cost × discount factor. Tit-for-tat in iterated Prisoner's Dilemma (Axelrod-Hamilton 1981).
Trivers 1971: altruistic behaviour evolves when recipients reciprocate, provided benefit > cost × discount factor. Tit-for-tat in iterated Prisoner's Dilemma (Axelrod-Hamilton 1981).