Norm of reciprocity refers to the assumption that others will treat us the way we treat them, example: if we help someone, he/she will help us. Norm of reciprocity, moreover, is the notion that it is acceptable and justifiable to treat someone else in the way they have treated you. It is a social standard that enjoins individuals to pay back in kind what they receive from others; the principle that we should give back in return any favors that are done for us; the cultural norm that you are obligated to return in full value what you receive.