100 Things Every Presenter Needs to Know About People

99. People Will Act In Order to Relieve a Sense of Obligation

If I give you a gift or do you a favor, you will feel indebted to me. You will want to give me a gift or do me a favor in return; possibly to be nice, but mainly to get rid of the feeling of indebtedness. This is a largely unconscious feeling, and it is quite strong. This is called reciprocity.

The theory is that this gift-giving and favor-swapping developed in human societies because it is useful in the survival of the species. If one person gives someone something (food, shelter, money, a gift, or a favor), that person will trigger the indebtedness. If the person who did the gifting finds him or herself in need of something in the future, he can “call in” the favor. These “deals” ...