“Is there one word which may serve as a rule of practice all one’s life?” The Master said, “Is not reciprocity such a word?”
Confucius, The Analects, Book 15, Chapter 23. (4th C. BP)
A man ought to be a friend to his friend and repay gift with gift. People should meet smiles with smiles and lies with treachery. A man ought to be a friend to his friend and also to his friend’s friend. But no one should be friendly with a friend of his foe.
The Edda (1923[13th C.]) verses 42, 43
Cooperation is common in humans in large part because people are motivated by social preferences: they care about the well-being of others and value fairness and other norms of decent behavior. Our explanation is that these social preferences are the ...