How we change what others think, feel, believe and do
This is a very common social norm which says that if I give something to you or help you in any way, then you are obliged to return the favor.
This norm is so powerful, it allows the initial giver to:
Reciprocity also works at the level of liking. We like people who like us, and dislike those who dislike us. This can create a self-fulfilling prophecy.
Kunz and Woolcott sent Christmas cards to a number of people he did not know. Most sent a card back (and they got onto the permanent Christmas list of some).
Hari Krishna people have used this by giving passers-by a small plastic flower and then asking for a donation in return.
Give people things, whether it is your time or money. It helps if you give them something they truly appreciate. Do not give them too much, lest they feel oppressed by their obligation. Ask for something in return.
If people give you something, say thank you (which is giving them something back in return!). When they ask for something in return, say no. Be polite (giving them something else). Or turn the tables, giving them something you don’t want, then ask them for something.
Always be aware of trickery when people you hardly know offer you something, especially if they ask for something from you in return.