Altruism
Reciprocal altruism. A person is more likely to help another if there is a chance that the other person will help them in return, whether immediately or eventually. This is about reciprocity. Many people cooperate if and only if others cooperate in return. Reputation may become important in this. A person with a good reputation for reciprocity have a higher chance of receiving help even from persons they have had no direct interactions with previously.