Psychologists of the Caribbean - The Norm of Reciprocity

- starring Johnny Depp, Orlando Bloom and Oktay Ülker

You want or need someone to do you a favor, but you don't know how to achieve this? If that person is a close friend or family member you can most likely rely on altruism. But what if that person is just a stranger? If this is the case, it can be really hard to get someone to do you a favor. 

If you think pirates only search for treasures and drink rum you are mistaken. They can even use the norm of reciprocity so that other people do them a favor! Below an example is given.

William Turner wants to save Elizabeth Swann who is on the Black Pearl, but in order to do so he needs to get to the ship. Captain Jack Sparrow is able to bring Will to the Black Pearl. Now Will makes use of the norm of reciprocity: he promises Captain Sparrow to free him, who afterwards is obligated to return the favor and bring Will to the ship. As seen in this scene, after hearing that Will can free him, Captain Sparrow offers Will that he can bring him to the ship in return.

The norm of reciprocity is used everywhere; in movies and our daily lives. It is indeed a well known and researched phenomenon. The likelihood of someone returning a favor after doing them a favor is higher, even without a verbal agreement as in the video. But actually there is an interesting fact about it which isn't shown in the video, which is described below.

Burger, Sanchez, Imberi and Grande (2009) conducted an experiment to find out more about the norm of reciprocity. Their study supports the effect. In their study, participants were either given a bottle of water by a confederate or not. Later they were asked to fill out a questionnaire at home and bring it back a few days later. However, Burger et al. added another variable to the experiment: one group was told that the confederate would recieve the questionnaire personally and the other group that the confederate wouldn't be present.

As seen in this table people who recieved a favor were more likely to return the favor (favor: 17/60 vs. no favor: 3/30). These results can be explained by the norm of reciprocity. But interestingly people returned a favor even if the confederate wasn't present (anonymous: 12/60 vs. non-anonymous: 8/60). This shows that for those people the norm of reciprocity is an internalizied social norm.

To put it in a nutshell, this article supports the general idea of the norm of reciprocity, which can also be seen in the short video. Additionally it shows that returning a favor doesn't depend on the fact whether the initial favor-giver notices it or not. So, to get a stranger to do you a favor, you should grant him a favor first (this works especially if you need to get to the Black Pearl and grant other pirates their freedom)!


Burger, J. M., Sanchez, J., Imberi, J. E., & Grande, L. R. (2009). The norm of reciprocity as an internalized social norm: Returning favors even when no one finds out. Social Influence, 4(1), 11-17.