norm of reciprocity
A social psychology term describing the expectation that people will respond to a positive action with another positive action, and to a negative action with a negative one.
The norm of reciprocity is often used in marketing and negotiation techniques.
小さな贈り物を受け取ると、返報性の原理によってお返しをしたくなる。
When you receive a small gift, the norm of reciprocity makes you want to give something in return.
互恵性 (reciprocity) is a broader concept of mutual benefit, while 返報性の原理 specifically refers to the psychological principle that people feel obligated to return favors or injuries.
Compound of 返報 (repayment, reciprocation), 性 (-ness, nature), and 原理 (principle). A calque of the English psychological term 'norm of reciprocity'.