The psychologist Hwang Kwang-kuo built a model of how Chinese people decide on a request. Starting from Fei Xiaotong’s idea of ties that are closer or more distant, he divides relationships into three kinds: expressive, mixed and instrumental.
Each kind follows its own rule. For expressive ties, the rule of need applies. For instrumental ties, the rule of fairness applies. For mixed ties, the person who controls the resource follows the rule of renqing (人情). He weighs what helping would cost against the return that may come in the future.